doctor of engineering, Tokyo Institute of Technology

Natural sciences, Semiconductors, optical and atomic physics

Apr. 2024 - Present
The University of Electro-Communications, Institute for Laser Science, Director, Japan

01 Jun. 2022
電気通信大学, レーザー新世代研究センター, 副センター長

01 Apr. 2021
Institute for Laser Science, Univ, of electro-communications, レーザー新世代研究センター, Professor

01 Oct. 2010 - 31 Mar. 2021
Institute for Laser Science, Univ, of electro-communications, レーザー新世代研究センター, Associate Professor

01 Dec. 2007 - 26 Jul. 2011
国立研究開発法人理化学研究所, Ｘ線自由電子レーザー計画推進本部, 研究員

Apr. 1995 - Mar. 1998
National Astronomical Observatory of Japan, spce time, 日本学術振興会特別研究員, Japan

Mar. 1994
Tokyo Institute of Technology, Graduate School, Division of Integrated Science and Engineering, 物理情報専攻

Mar. 1991
The University of Tokyo, Graduate School, Division of Science, 相関理化学専攻

Mar. 1989
The University of Tokyo, Faculty of Engineering, 資源開発工学科

01 Apr. 2022
委員, 新方式精密計測による物理・工学的変革を目指す回路技術調査専門委員会

01 Apr. 2019 - 31 Mar. 2022
委員, 精密計測を元に科学技術に変革をもたらす回路技術調査専門委員会

01 Jun. 2018 - 01 Jun. 2020
審査委員, 応用物理学会論文賞委員会, Society

01 Apr. 2016 - 31 Mar. 2019
委員, 超精密周波数計測とその比較技術による回路技術調査専門委員会

01 Apr. 2016 - 01 Jun. 2018
プログラム委員, Conference on Advanced Lasers and Photon Sources, Society

01 Apr. 2018
委員, 電気電子工学委員会第24期URSI分科会電磁波計測小委員会

01 Apr. 2015 - 31 Mar. 2018
委員長, 電気電子工学委員会第23期URSI分科会電磁波計測小委員会, Society

Apr. 2001 - Apr. 2007
プログラム委員, 応用物理学会, Society

01 Apr. 2005
委員, 宇宙理学委員会, Society

High-power 813-nm Tm3+-doped ZBLAN fiber MOPA with signal-light photodarkening suppression
Eiji Kajikawa; Tomohiro Ishii; Kasuhiko Ogawa; Mitsuru Musha
Applied Optics, Optical Society of America, 60, 23, 6776-6780, 30 Jul. 2021, Peer-reviwed
Scientific journal, English

Laser-based satellite positioning system for space gravitational wave detector DECIGO
Mitsuru Musha; Mika Tajiri; Kei Akmi; Yuichi Takeuchi
Proceeding SPIE, 11852, 1185240-2, 28 Mar. 2021, Peer-reviwed
International conference proceedings, English

Development of an all PM mode lock fiber laser for space borne frequency reference
Yuichi Takeuchi; Ryota Saito; Shun Endo; Kana Matsusaka; Mitsuru Musha
Proceeding SPIE, 11852, 118523O-2, 28 Mar. 2021, Peer-reviwed
International conference proceedings, English

Current status of space gravitational wave antenna DECIGO and B-DECIGO
S.Kawamura; M.Ando; N.Seto; S.Sato; M.Musha et
Progress on Theoretical and Experimental Physics, Japanese Physical Society, 2021, 05A105, 22 Feb. 2021, Peer-reviwed
Scientific journal, English

Improvement of the target sensitivity in DECIGO by optimizing its parameters for quantum noise including the effect of diffraction loss
T.Ishikawa; S.Iwaguchi; Y.Michimura; M.Ando; R.Yamada; I.Watanabe; K.Nagano; T.Akutsu; K.Komori; M.Musha; T.Naito; T.Morimoto; S.Kawamura
Galaxies, MDPI, 9, 14, Jan. 2021, Peer-reviwed
Scientific journal, English

Quantum noise in a Fabry-Perot Interferometer including the influence of diffraction loss of light
S.Iwaguchi; T.Ishikawa; M.Ando; Y.Michimura; K.Komori; K.Nagano; T.Akutsu; M.Musha; R.Yamada; I.Watanabe; T.Naito; T.Morimoto; S.Kawamura
Galaxies, MDPI, 9, 1, 9-9, Jan. 2021, Peer-reviwed, The DECi-hertz Interferometer Gravitational wave Observatory (DECIGO) is designed to detect gravitational waves at frequencies between 0.1 and 10 Hz. In this frequency band, one of the most important science targets is the detection of primordial gravitational waves. DECIGO plans to use a space interferometer with optical cavities to increase its sensitivity. For evaluating its sensitivity, diffraction of the laser light has to be adequately considered. There are two kinds of diffraction loss: leakage loss outside the mirror and higher-order mode loss. These effects are treated differently inside and outside of the Fabry-Perot (FP) cavity. We estimated them under the conditions that the FP cavity has a relatively high finesse and the higher-order modes do not resonate. As a result, we found that the effects can be represented as a reduction of the effective finesse of the cavity with regard to quantum noise. This result is useful for optimization of the design of DECIGO. This method is also applicable to any FP cavities with a relatively small beam cut and the finesse sufficiently higher than 1.
Scientific journal, English

The current status of contribution activities in Japan for LISA
Kiwamu Izumi; Norichika Sago; Tomotada Akutsu; Masaki Ando; Mitsuru Musha e
Progress of Theoretical and Experimental Physics, Oxford Academic, ptta124, 1, 14 Aug. 2020, Peer-reviwed, Abstract

LISA is a space gravitational-wave mission that will open the unexplored gravitational-wave frequency window at around millihertz, shedding light on the study of supermassive black holes and the nature of gravity. The LISA project has been propelled by international collaboration in order to maximize the scientific outcome. With the aim of making scientifically important contributions to LISA, instrument and science groups were newly formed in Japan. This article summarizes the current status of the contribution activities conducted by each group to date, highlighting a few selected topics including the development of photoreceivers and theoretical studies on compact binaries and extreme mass ratio inspirals.
Scientific journal, English

Application of independent component analysis to the iKAGRA data
T.Akutsu; M.Ando; K.Arai; M.Musha et
Progress of Theoretical and Experimental Physics, Oxford Academic, 2020, 053F01, 28 Jun. 2020, Peer-reviwed
Scientific journal, English

Dual-wavelength-pumped Tm3+-doped ZBLAN fiber MOPA at 813 nm
Eiji Kajikawa; Tomohiro Ishii; Takashi Kubo; Yu-ichi Takeuchi; Kazuhiko Ogawa; Mitsuru Musha
Optics Letters, Optical Society of America, 44, 11, 2875-2878, 30 May 2019, Peer-reviwed
Scientific journal, English

Stable and high power 515-nm lasers for the space gravitational wave detector: DECIGO
Aru Suemasa; Ayumi Snimo-oku; Shunsuke Ohtsuka; Masaki Nakamori; Mitsuru Musha
Proceeding of ICSO2018, 3c-1440, 09 Oct. 2018, Peer-reviwed
International conference proceedings, English

Novel satellite positioning system using acousto-optic deflector
Mitsuru Musha; Aru Suemasa; Kei Akami
Proceeding of ICSO2018, 14c-1220, 09 Oct. 2018, Peer-reviwed
International conference proceedings, English

Space Gravitational Wave Antenna DECIGO and B-DECIGO
Kawamura, Seiji; Nakamura, Takashi; Ando, Masaki; Seto, Naoki; Akutsu, Tomotada; Funaki, Ikkoh; Ioka, Kunihito; K; a, Nobuyuki; Kawano, Isao; Musha, Mitsuru; Nakazawa, Kazuhiro; Sato, Shuichi; Takashima, Takeshi; Tanaka, Takahiro; Tsubono, Kimio; Yokoyama, Jun'ichi; Agatsuma, Kazuhiro; Aoyanagi, Koh-suke; Arai, Koji; Araya, Akito; Aritomi, Naoki; Asada, Hideki; Aso, Yoichi; Chen, Dan; Chiba, Takeshi; Ebisuzaki, Toshikazu; Eguchi, Satoshi; Ejiri, Yumiko; Enoki, Motohiro; Eriguchi, Yoshiharu; Fujimoto, Masa-Katsu; Fujita, Ryuichi; Fukushima, Mitsuhiro; Futamase, Toshifumi; Gondo, Rina; Harada, Tomohiro; Hashimoto, Tatsuaki; Hayama, Kazuhiro; Hikida, Wataru; Himemoto, Yoshiaki; Hirabayashi, Hisashi; Hiramatsu, Takashi; Hong, Feng-Lei; Horisawa, Hideyuki; Hosokawa, Mizuhiko; Ichiki, Kiyotomo; Ikegami, Takeshi; Inoue, Kaiki T; Ishihara, Hideki; Ishikawa, Takehiko; Ishizaki, Hideharu; Ito, Hiroyuki; Itoh, Yousuke; Izumi, Kiwamu; Kanemura, Shinya; Kawashima, Nobuki; Kawazoe, Fumiko; Kishimoto, Naoko; Kiuchi, Kenta; Kobayashi, Shiho; Kohri, Kazunori; Koizumi, Hiroyuki; Kojima, Yasufumi; Kokeyama, Keiko; Kokuyama, Wataru; Kotake, Kei; Kozai, Yoshihide; Kunimori, Hiroo; Kuninaka, Hitoshi; Kuroda, Kazuaki; Kuroyanagi, Sachiko; Maeda, Kei-ichi; Matsuhara, Hideo; Matsumoto, Nobuyuki; Michimura, Yuta; Miyakawa, Osamu; Miyamoto, Umpei; Miyoki, Shinji; Morimoto, Mutsuko Y; Morisawa, Toshiyuki; Moriwaki, Shigenori; Mukohyama, Shinji; Nagano, Shigeo; Nakamura, Kouji; Nakano, Hiroyuki; Nakao, Kenichi; Nakasuka, Shinichi; Nakayama, Yoshinori; Nishida, Erina; Nishizawa, Atsushi; Niwa, Yoshito; Noumi, Taiga; Obuchi, Yoshiyuki; Ohishi, Naoko; Ohkawa, Masashi; Okada, Kenshi; Okada, Norio; Okutomi, Koki; Oohara, Kenichi; Sago, Norichika; Saijo, Motoyuki; Saito, Ryo; Sakagami, Masaaki; Sakai, Shin-ichiro; Sakata, Shihori; Sasaki, Misao; Sato, Takashi; Shibata, Masaru; Shibata, Kazunori; Shimo-oku, Ayumi; Shinkai, Hisaaki; Shoda, Ayaka; Somiya, Kentaro; Sotani, Hajime; Suemasa, Aru; Sugiyama, Naoshi; Suwa, Yudai; Suzuki, Rieko; Tagoshi, Hideyuki; Takahashi, Fuminobu; Takahashi, Kakeru; Takahashi, Keitaro; Takahashi, Ryutaro; Takahashi, Ryuichi; Takahashi, Hirotaka; Akiteru, Takamori; Takano, Tadashi; Tanaka, Nobuyuki; Taniguchi, Keisuke; Taruya, Atsushi; Tashiro, Hiroyuki; Torii, Yasuo; Toyoshima, Morio; Tsujikawa, Shinji; Ueda, Akitoshi; Ueda, Ken-ichi; Ushiba, Takafumi; Utashima, Masayoshi; Wakabayashi, Yaka; Yagi, Kent; Yamamoto, Kazuhiro; Yamazaki, Toshitaka; Yoo, Chul-Moon; Yoshida, Shijun; Yoshino, Taizoh
International Journal of Modern Physics D, Springer, 0, ja, 371-377, 2018, Peer-reviwed
Scientific journal, English

超高感度レーザー干渉計を用いた重力波の直接検出
武者満
電子情報通信学会誌, 電子情報通信学会, J101-C, 01 Jan. 2018, Peer-reviwed, Invited
Scientific journal, Japanese

Construction of KAGRA: an underground gravitational-wave observatory
KAGRA Collaboration; Shoda, A; Ikenoue, B; Tatsumi, D; Uraguchi, F; Peña Arellano, F E; Ishizaki, H; Nakamura, K; Fukushima, M; Marchio, M; Barton, M A; Fujimoto, M -K; Hirata, N; Flaminio, R; Takahashi, R; Saitou, S; Zeidler, S; Akutsu, T; Tsuzuki, T; Aso, Y; Fujii, Y; Obuchi, Y; Ohishi, N; Ando, M; Baiotti, L; Park, J; Cho, K; Pinto, I M; Principe, M; DeSalvo, R; Matsushima, F; Tamura, H; Hashino, K; Kobayashi, K; Fujisawa, M; Kakizaki, M; Kanbara, S; Kanemura, S; Furuhata, T; Kagawa, T; Matsui, T; Moriwaki, Y; Sugimoto, Y; Nakano, H; Fujibayashi, S; Nakamura, T; Tanaka, T; Haino, S; Inoue, Y; Jia, D; Kakuhata, H; Miyake, K; Hasegawa, M; Nakano, M; Ioka, K; Kawaguchi, K; Shibata, M; Itoh, Y; Eda, K; Tsukada, L; Morisaki, S; Yokoyama, J; Kawazoe, F; Miener, T; Kim, C; Kim, J; Lee, H -W; Kim, J C; Son, E J; Oh, J J; Oh, S -H; Kim, W; Kojima, Y; Kotake, K; Kubo, K; Murakoshi, M; Someya, N; Ota, S; Nonomura, T; Sato, S; Lee, H -K; Takeda, H; Komori, K; Tsubono, K; Aritomi, N; Wada, S; Shimoda, T; Ushiba, T; Kuwahara, Y; Michimura, Y; Lin, C -Y; Majorana, E; Mano, S; Matsumoto, N; Mio, N; Ohmae, N; Morii, W; Suemasa, A; Musha, M; Nagano, S; Ni, W -T; Hagiwara, A; Kumar, R; Araki, S; Koike, S; Kume, T; Sato, Y; Kimura, N; Suzuki, T; Tomaru, T; Suwabe, H; Hirai, K; Oohara, K; Shiga, K; Ohkawa, M; Narita, T; Saito, T; Sato, T; Wakamatsu, T; Okino, K; Okutomi, K; Ono, Y; Sago, N; Saijo, M; Sakai, K; Takahashi, H; Ueki, S; Sasaki, Y; Sekiguchi, Y; Araya, A; Takamori, A; Uyeshima, M; Ogawa, T; Shikano, Y; Shinkai, H; Yamamoto, S; Starecki, T; Takada, S; Telada, S; Uehara, T; Mueller, C. L; Tanner, D B; Goetz, R; Ueno, K; van Putten, M H P M; Miyamoto, A; Nakao, H; Tagoshi, H; Yuzurihara, H; Nakao, K; Tanaka, K; Asano, M; Kaneyama, M; Toritani, M; K; a, N; Uchikata, N; Tsuchida, S; Arima, T; Kaji, T; Narikawa, T; Yokozawa, T; Kitaoka, Y; Yoon, T. H; Zhao, Y; Zheng, L; Bertolini, A; Hennes, E; van den Br; , J F J; van Heijningen, J V; Agatsuma, K; Yanagida, A; Arai, N; Hirayama, T; Sekiguchi, T; Utsuki, T; Akiyama, Y; Hashimoto, Y; Guscott, J; Morioka, M; Hayashida, Y; Yamaguchi, S; Oda, Y; Asada, H; Tokoku, C; Kumeta, A; Kasuya, J; Kato, J; Yano, K; Kawai, N; Atsuta, S; Harita, S; Yaginuma, T; Kataoka, Y; Muraki, Y; Susa, Y; Tachibana, Y; Somiya, K; Chen, D; Craig, K; Hasegawa, K; Kuroda, K; Miyo, K; Nagano, K; Ono, K; Enomoto, Y; Liu, Y; Sakakibara, Y; Hirose, E; Ishitsuka, H; Tanaka, H; Awai, K; Hayama, K; Kokeyama, K; Yamamoto, K; Kamiizumi, M; Nakano, M; Ohashi, M; Miyakawa, O; Kawamura, S; Miyoki, S; Kajita, T; Miyamoto, T; Sekiguchi, T; Uchiyama, T; Yamamoto, T; Saito, Y; Doi, K; Khalaidovski, A
Progress of Theoretical and Experimental Physics, Oxford Academic, Physical Society of Japan, 2018, 1, 013F01, Jan. 2018, Peer-reviwed
Scientific journal, English

Space Gravitational Wave Antenna DECIGO and B-DECIGO
Kawamura, Seiji; Nakamura, Takashi; Ando, Masaki; Seto, Naoki; Akutsu, Tomotada; Funaki, Ikkoh; Ioka, Kunihito; K; a, Nobuyuki; Kawano, Isao; Musha, Mitsuru; Nakazawa, Kazuhiro; Sato, Shuichi; Takashima, Takeshi; Tanaka, Takahiro; Tsubono, Kimio; Yokoyama, Jun'ichi; Agatsuma, Kazuhiro; Aoyanagi, Koh-suke; Arai, Koji; Araya, Akito; Aritomi, Naoki; Asada, Hideki; Aso, Yoichi; Chen, Dan; Chiba, Takeshi; Ebisuzaki, Toshikazu; Eguchi, Satoshi; Ejiri, Yumiko; Enoki, Motohiro; Eriguchi, Yoshiharu; Fujimoto, Masa-Katsu; Fujita, Ryuichi; Fukushima, Mitsuhiro; Futamase, Toshifumi; Gondo, Rina; Harada, Tomohiro; Hashimoto, Tatsuaki; Hayama, Kazuhiro; Hikida, Wataru; Himemoto, Yoshiaki; Hirabayashi, Hisashi; Hiramatsu, Takashi; Hong, Feng-Lei; Horisawa, Hideyuki; Hosokawa, Mizuhiko; Ichiki, Kiyotomo; Ikegami, Takeshi; Inoue, Kaiki T; Ishihara, Hideki; Ishikawa, Takehiko; Ishizaki, Hideharu; Ito, Hiroyuki; Itoh, Yousuke; Izumi, Kiwamu; Kanemura, Shinya; Kawashima, Nobuki; Kawazoe, Fumiko; Kishimoto, Naoko; Kiuchi, Kenta; Kobayashi, Shiho; Kohri, Kazunori; Koizumi, Hiroyuki; Kojima, Yasufumi; Kokeyama, Keiko; Kokuyama, Wataru; Kotake, Kei; Kozai, Yoshihide; Kunimori, Hiroo; Kuninaka, Hitoshi; Kuroda, Kazuaki; Kuroyanagi, Sachiko; Maeda, Kei-ichi; Matsuhara, Hideo; Matsumoto, Nobuyuki; Michimura, Yuta; Miyakawa, Osamu; Miyamoto, Umpei; Miyoki, Shinji; Morimoto, Mutsuko Y; Morisawa, Toshiyuki; Moriwaki, Shigenori; Mukohyama, Shinji; Nagano, Shigeo; Nakamura, Kouji; Nakano, Hiroyuki; Nakao, Kenichi; Nakasuka, Shinichi; Nakayama, Yoshinori; Nishida, Erina; Nishizawa, Atsushi; Niwa, Yoshito; Noumi, Taiga; Obuchi, Yoshiyuki; Ohishi, Naoko; Ohkawa, Masashi; Okada, Kenshi; Okada, Norio; Okutomi, Koki; Oohara, Kenichi; Sago, Norichika; Saijo, Motoyuki; Saito, Ryo; Sakagami, Masaaki; Sakai, Shin-ichiro; Sakata, Shihori; Sasaki, Misao; Sato, Takashi; Shibata, Masaru; Shibata, Kazunori; Shimo-oku, Ayumi; Shinkai, Hisaaki; Shoda, Ayaka; Somiya, Kentaro; Sotani, Hajime; Suemasa, Aru; Sugiyama, Naoshi; Suwa, Yudai; Suzuki, Rieko; Tagoshi, Hideyuki; Takahashi, Fuminobu; Takahashi, Kakeru; Takahashi, Keitaro; Takahashi, Ryutaro; Takahashi, Ryuichi; Takahashi, Hirotaka; Akiteru, Takamori; Takano, Tadashi; Tanaka, Nobuyuki; Taniguchi, Keisuke; Taruya, Atsushi; Tashiro, Hiroyuki; Torii, Yasuo; Toyoshima, Morio; Tsujikawa, Shinji; Ueda, Akitoshi; Ueda, Ken-ichi; Ushiba, Takafumi; Utashima, Masayoshi; Wakabayashi, Yaka; Yagi, Kent; Yamamoto, Kazuhiro; Yamazaki, Toshitaka; Yoo, Chul-Moon; Yoshida, Shijun; Yoshino, Taizoh
International Journal of Modern Physics D, World Scientific, 0, ja, 1845001, 2018, Peer-reviwed
Scientific journal, English

Developments of high frequency and intensity stabilized lasers for space gravitational wave detector DECIGO/B-DECIGO
Aru Suemasa; Ayumi Shimo-oku; Ken’ichi Nakagawa; Mitsuru Musha
CEAS Space Journal, Springer-Verlag Wien, 9, 4, 485-491, 01 Dec. 2017, Peer-reviwed, In Japan, not only the ground-based gravitational wave (GW) detector mission KAGRA but also the space GW detector mission DECIGO (DECi-hertz Interferometer Gravitational wave Observatory) and its milestone mission B-DECIGO have been promoted. The designed strain sensitivity of DECIGO and B-DECIGO are δL/L <
 10−23. Since the GW detector requires high power and highly-stable light source, we have developed the light source with high frequency and intensity stability for DECIGO and B-DECIGO. The frequency of the Yb-doped fiber DFB lasers are stabilized to the iodine saturated absorption at 515 nm, and the intensity of the laser at 1 Hz (observation band) is stabilized by controlling the pump source of an Yb-doped fiber amplifier. The intensity of the laser at 200 kHz (modulation band) is also stabilized using an acousto-optic modulator to improve the frequency stability of the laser. In the consequences, we obtain the frequency stability of δf = 0.4 Hz/√Hz (in-loop) at 1 Hz, and the intensity stability of δI/I = 1.2 × 10−7/√Hz (out-of-loop) and δI/I = 1.5 × 10−7/√Hz (in-loop) at 1 Hz and 200 kHz, respectively.
Scientific journal, English

Optical frequency synthesizer for precision spectroscopy of Rydberg states of Rb atoms
Naoto Watanabe; Hikaru Tamura; Mitsuru Musha; Ken’ichi Nakagawa
Japanese Journal of Applied Physics, The Japan Society of Applied Physics, 56, 11, 112401-112401, 12 Oct. 2017, Peer-reviwed, We have developed an optical frequency synthesizer for the precision spectroscopy of highly excited Rydberg states of Rb atoms. This synthesizer can generate a widely tunable 480 nm laser light with an optical power of 150 mW and an absolute frequency uncertainty of less than 100 kHz using a high-repetition-rate (325 MHz) Er fiber-based optical frequency comb and a tunable frequency-doubled diode laser at 960 nm. We demonstrate the precision two-photon spectroscopy of the Rydberg states of ⁸⁷Rb atoms by observing the electromagnetically induced transparency in a vapor cell, and measure the absolute transition frequencies of ⁸⁷Rb to nD (n = 53–92) and nS (n = 60–90) Rydberg states with an uncertainty of less than 250 kHz. It is the first direct frequency measurements of these transitions using an optical frequency comb.
Scientific journal, English

The status of DECIGO
Shuichi Sato; Seiji Kawamura; Masaki Ando; Takashi Nakamura; Kimio Tsubono; Akito Araya; Ikkoh Funaki; Kunihito Ioka; Nobuyuki Kanda; Shigenori Moriwaki; Mitsuru Musha; Kazuhiro Nakazawa; Kenji Numata; Shin Ichiro Sakai; Naoki Seto; Takeshi Takashima; Takahiro Tanaka; Kazuhiro Agatsuma; Koh Suke Aoyanagi; Koji Arai; Hideki Asada; Yoichi Aso; Takeshi Chiba; Toshikazu Ebisuzaki; Yumiko Ejiri; Motohiro Enoki; Yoshiharu Eriguchi; Masa Katsu Fujimoto; Ryuichi Fujita; Mitsuhiro Fukushima; Toshifumi Futamase; Katsuhiko Ganzu; Tomohiro Harada; Tatsuaki Hashimoto; Kazuhiro Hayama; Wataru Hikida; Yoshiaki Himemoto; Hisashi Hirabayashi; Takashi Hiramatsu; Feng Lei Hong; Hideyuki Horisawa; Mizuhiko Hosokawa; Kiyotomo Ichiki; Takeshi Ikegami; Kaiki T. Inoue; Koji Ishidoshiro; Hideki Ishihara; Takehiko Ishikawa; Hideharu Ishizaki; Hiroyuki Ito; Yousuke Itoh; Nobuki Kawashima; Fumiko Kawazoe; Naoko Kishimoto; Kenta Kiuchi; Shiho Kobayashi; Kazunori Kohri; Hiroyuki Koizumi; Yasufumi Kojima; Keiko Kokeyama; Wataru Kokuyama; Kei Kotake; Yoshihide Kozai; Hideaki Kudoh; Hiroo Kunimori; Hitoshi Kuninaka; Kazuaki Kuroda; Kei Ichi Maeda; Hideo Matsuhara; Yasushi Mino; Osamu Miyakawa; Shinji Miyoki; Mutsuko Y. Morimoto; Tomoko Morioka; Toshiyuki Morisawa; Shinji Mukohyama; Shigeo Nagano; Isao Naito; Kouji Nakamura; Hiroyuki Nakano; Kenichi Nakao; Shinichi Nakasuka; Yoshinori Nakayama; Erina Nishida; Kazutaka Nishiyama; Atsushi Nishizawa; Yoshito Niwa; Taiga Noumi; Yoshiyuki Obuchi; Masatake Ohashi; Naoko Ohishi; Masashi Ohkawa; Norio Okada; Kouji Onozato; Kenichi Oohara; Norichika Sago; Motoyuki Saijo; Masaaki Sakagami; Shihori Sakata; Misao Sasaki
Journal of Physics: Conference Series, 840, 1, 01 Jun. 2017, Peer-reviwed, © Published under licence by IOP Publishing Ltd. DECIGO (DECi-hertz Interferometer Gravitational wave Observatory) is the planned Japanese space gravitational wave antenna, aiming to detect gravitational waves from astrophysically and cosmologically significant sources mainly between 0.1 Hz and 10 Hz and thus to open a new window for gravitational wave astronomy and for the universe. DECIGO will consists of three drag-free spacecraft arranged in an equilateral triangle with 1000 km arm lengths whose relative displacements are measured by a differential Fabry-Perot interferometer, and four units of triangular Fabry-Perot interferometers are arranged on heliocentric orbit around the sun. DECIGO is vary ambitious mission, we plan to launch DECIGO in era of 2030s after precursor satellite mission, B-DECIGO. B-DECIGO is essentially smaller version of DECIGO: B-DECIGO consists of three spacecraft arranged in an triangle with 100 km arm lengths orbiting 2000 km above the surface of the earth. It is hoped that the launch date will be late 2020s for the present..
International conference proceedings, English

High power narrow-linewidth linearly-polarized 1610 nm Er:Yb all-fiber MOPA
Eisuke Fujita; Yutaka Mashiko; Seira Asaya; Mitsuru Musha; Masaki Tokurakawa
OPTICS EXPRESS, OPTICAL SOC AMER, 24, 23, 26255-26260, Nov. 2016, Peer-reviwed, We developed a narrow-linewidth linearly-polarized all-PM-fiber MOPA at the wavelength of 1610 nm. The MOPA consists of a DFB laser diode seed source and three amplifier stages with three different gain fibers. The first amplifier stage employed an Er doped fiber and the second and third amplifier stages employed Er: Yb co-doped fibers. The maximum output power was 8 W. Linewidth of 25 MHz and polarization extinction ratio of 28 dB was obtained. At the maximum output power, no ASE component around 1.55 mu m or 1 mu m was observed. (C) 2016 Optical Society of America
Scientific journal, English

Space gravitational wave detector DECIGO/Pre-DECIGO
Mitsuru Musha
Proceedings of ICSO 2016, 12b-21, 18 Oct. 2016, Peer-reviwed
International conference proceedings, English

Developments of highly frequency and intensity stabilized laser for space gravitational wave detector DECIGO/Pre-DECIGO
Aru Suemasa; Ayumi Shimo-oku; Ken'ichi Nakagawa; Mitsuru Musha
Proceedings of ICSO 2016, 2c-29, 18 Oct. 2016, Peer-reviwed
International conference proceedings, English

Pre-DECIGO can get the smoking gun to decide the astrophysical or cosmological origin of GW150914-like binary black holes
Takashi Nakamura; Masaki Ando; Tomoya Kinugawa; Hiroyuki Nakano; Kazunari Eda; Shuichi Sato; Mitsuru Musha; Tomotada Akutsu; Takahiro Tanaka; Naoki Seto; Nobuyuki Kanda; Yousuke Itoh
Progress of Theoretical and Experimental Physics, Physical Society of Japan, 2016, 9, 093E01, 04 Jul. 2016, Peer-reviwed, Pre-DECIGO consists of three spacecraft arranged in an equilateral triangle
with 100km arm lengths orbiting 2000km above the surface of the earth. It is
hoped that the launch date will be in the late 2020s.
Pre-DECIGO has one clear target: binary black holes (BBHs) like GW150914 and
GW151226. Pre-DECIGO can detect $\sim 30M_\odot-30M_\odot$ BBH mergers up to
redshift $z\sim 30$. The cumulative event rate is $\sim 1.8\times 10^{5}\,{\rm
events~yr^{-1 } }$ in the Pop III origin model of BBHs like GW150914, and it
saturates at $z\sim 10$, while in the primordial BBH (PBBH) model, the
cumulative event rate is $ \sim 3\times 10^{4}\,{\rm events~ yr^{-1 } }$ at
$z=30$ even if only $0.1\%$ of the dark matter consists of PBHs, and it is
still increasing at $z=30$. In the Pop I/II model of BBHs, the cumulative event
rate is $(3-10)\times10^{5}\,{\rm events~ yr^{-1 } }$ and it saturates at $z \sim
6$. We present the requirements on orbit accuracy, drag free techniques, laser
power, frequency stability, and interferometer test mass. For BBHs like
GW150914 at 1Gpc, SNR$\sim 90$ is achieved with the definition of Pre-DECIGO in
the $0.01-100$Hz band. Pre-DECIGO can measure the mass spectrum and the
$z$-dependence of the merger rate to distinguish various models of BBHs like
GW150914.
Pre-DECIGO can also predict the direction of BBHs at $z=0.1$ with an accuracy
of $\sim 0.3\,{\rm deg}^2$ and a merging time accuracy of $\sim 1$s at about a
day before the merger so that ground-based GW detectors further developed at
that time as well as electromagnetic follow-up observations can prepare for the
detection of merger in advance. For intermediate mass BBHs at a large redshift
$z > 10$, the QNM frequency after the merger can be within the Pre-DECIGO band
so that the ringing tail can also be detectable to confirm the Einstein theory
of general relativity with SNR$\sim 35$.
[abridged]
Scientific journal, English

Measurement of absolute transition frequencies of ⁸⁷Rb Rydberg states using optical frequency comb
Watanabe Naoto; Naka Nobunaga; Tamura Hikaru; Musha Mitsuru; Nakagawa Ken'ichi
Meeting Abstracts of the Physical Society of Japan, The Physical Society of Japan, 71, 576-576, 2016,

我々は、レーザー冷却の研究で用いるために可視から近赤外領域までの広帯域な光周波数基準光源の開発を行っている。この周波数基準光源はErファイバー光周波数コムを利用して実現をする。実用的な基準光源の一例として、初めに単一^87^Rb原子を用いた量子情報処理の研究のためのリドベルグ状態励起用基準光源の開発を行っている。本発表では、装置の評価のために^87^Rbリドベルグ状態の絶対周波数測定を行い、先行研究の結果と比較を行う。

Japanese

A Watt-class narrow-linewidth MOFPA system at 813 nm by usinga Tm3+-doped fluoride fiber amplifier for the Sr optical lattice clock
Eiji Kajikawa; Yu-ichi Takeuchi; Kenta Kohno; Ken'ichi Nakagawa; Mitsuru Musha
Proceedings of CLEO EUROPE 2015, European Physical Society, CJ-14, 2-2, 20 Jun. 2015, Peer-reviwed
International conference proceedings, English

23pDJ-3 Space Gravitational Wave Antenna DECIGO (61) : frequency-stabilized laser
Musha Mitsuru; Suemasa Aru; Nakagawa Ken'ichi; DECCIGO workgroup
Meeting Abstracts of the Physical Society of Japan, The Physical Society of Japan (JPS), 70, 461-461, 2015
Japanese

Japanese space gravitational wave antenna DECIGO and DPF
Mitsuru Musha; DECIGO collaboratopns
Proceeding OF ICSO 2014, 8B-4, 07 Oct. 2014, Peer-reviwed
International conference proceedings, English

Highly frequency-stabilized laser for space gravitational wave detector DECIGO/DPF
Aru Suemasa; Ken'ichi Nakagawa; Mitsuru Musha
Proceedings of ICSO2014, 10A-4, 07 Oct. 2014, Peer-reviwed
International conference proceedings, English

1 W single-frequency Tm-doped ZBLAN fiber MOPA around 810 nm
Kenta Kohno; Yu-ichi Takeuchi; Toshiyuki Kitamura; Ken'ichi Nakagawa; Ken-ichi Ueda; Mitsuru Musha
OPTICS LETTERS, OPTICAL SOC AMER, 39, 7, 2191-2193, Apr. 2014, Peer-reviwed, We demonstrate a tunable narrow-linewidth fiber MOPA system around 810 nm for the light source of the Sr optical lattice clock. The coherent cw light source with a wavelength of 813.42 nm was generated by a combination of a narrow linewidth external-cavity laser diode and a Tm-doped ZBLAN fiber amplifier, which was upconversion-pumped by an Yb-doped fiber laser at 1064 nm. The maximum output power of 1.1 W was obtained with the launched power of 17 W, which is the highest power obtained from a Tm-doped fiber amplifier ever reported. (C) 2014 Optical Society of America
Scientific journal, English

Progress of highly frequency-stabilized Lasers and their applications
Mitsuru Musha
レーザー研究, レーザー学会, 42, 1, 5-11, Jan. 2014
Research institution, Japanese

A Space-borne Frequency-stabilized Laser for Gravitational Wave Detector
Mitsuru Musha; Aru Suemasa; Kenb'ichi Nakagawa; Ken-ichi Ueda; DECIGO Collaborations
Proceedings of AP-RASC 2013, A4a-5, Sep. 2013, Peer-reviwed
International conference proceedings, English

Development of an 813-nm Tm-doped ZBLAN fiber amplifier for the Sr optical lattice clock
Yu-ichi Takeuchi; Masanori Uehara; Kenta Kohno; Mitsuru Musha; Ken'ichi Nakagawa; Ken-ichi Ueda
2013 CONFERENCE ON AND INTERNATIONAL QUANTUM ELECTRONICS CONFERENCE LASERS AND ELECTRO-OPTICS EUROPE (CLEO EUROPE/IQEC), IEEE, CJ-8.6, 2013, Peer-reviwed
International conference proceedings, English

Developments of a space-borne stabilized laser for DECIGO and DPF
Mitsuru Musha; Ken'ichi Nakagawa; Ken-ichi Ueda
Proceedings of Internatinal Conference on Space Optics, w9-2.2, Sep. 2012, Peer-reviwed
International conference proceedings, English

Development of precision signal dissemination system using optical fiber link
Mitsuru Musha
応用物理, 80, 12, 1053-1057, Dec. 2011, Peer-reviwed
Scientific journal, Japanese

A Highly-stabilized Light Source for the Space Gravitational Wave Detector DECIGO and DPF
Mitsuru Musha; Shin-ya Horiuchi; Ken'ichi Nakagawa; Ken-ichi Ueda
Proc. of CLEO-Europe 2011, CA5.2, May 2011, Peer-reviwed
International conference proceedings, English

Reflectivity Measurements of Metals for LCGT Thermal Radiation Shields at Cryogenic Temperature and Wavelength of 10 um.
Y.Sakakibara; K.Kuroda; M.Ohashi; R.Takahashi; S.Miyoki; T.Uchiyama; Y.Saito; T.Suzuki; A.Yamamoto; T.Haruyama; N.Kimura; N.Mio, S; Moriwaki; N.Ohmae; M.Musha
Journal of Cryogenic and Superconductivity Society of Japan, 46, 434-440, 2011, Peer-reviwed
Scientific journal, English

Developments of the light source for DECIGO and DPF
Mitsuru Musha; Ken'Ichi Nakagawa; Ken-Ichi Ueda
2011 International Conference on Space Optical Systems and Applications, ICSOS'11, 378-380, 2011, Peer-reviwed, We have developed the light source for the space gravitational wave detector, DECIGO, and its pathfinder, DPF. The frequency stability of the 1 Hz/Hz1/2 at Fourier frequency around 1Hz, and output power of 10W are required as the light source for DECIGO. We will report the breadboard model of the frequency-stabilized Yb:YAG laser for DPF whose frequency is stabilized in reference to the saturated absorption of iodine molecules around 515nm, and the fiberMOPA system for DECIGO. © 2011 IEEE.
International conference proceedings, English

Precision timing and Rf signal dissemination for XFEL by delivering optical frequency comb through length-stabilized fiber
Mitsuru Musha; Toshio Ryuo; Ken'ichi Nakagawa; Ken-Ichi Ueda
2011 30th URSI General Assembly and Scientific Symposium, URSIGASS 2011, AGJ.8, 2011, Peer-reviwed, We have developed the precision timing and rf signal dissemination system for the X-ray free electron laser (XFEL), under construction in Japan. The optical frequency comb was transmitted through a 1-km length-stabilized optical fiber for disseminating both rf and timing signals. The phase fluctuations of the rf signals at 5.712 GHz was suppressed down to 0.0042 radian that is used for synchronizing linear accelerators, and the timing jitter between optical pulses are suppressed down to 50 fs that is used for providing X-ray trigger timing to the users, both of which satisfy the requirement of the XFEL. © 2011 IEEE.
International conference proceedings, English

Frequency measurement of a Sr optical lattice clock using a 120-km precision optical fiber link
Mitsuru Musha
レーザー研究, 38, 7, 505-511, Jul. 2010, Peer-reviwed
Scientific journal, Japanese

DECIGO: the Japanese Space Gravitational Wave Antenna
ANDO Masaki; KAWAMURA Seiji; SATO Shuichi; NAKAMURA Takashi; TSUBONO Kimio; ARAYA Akito; FUNAKI Ikkoh; IOKA Kunihito; KANDA Nobuyuki; MORIWAKI Shigenori; MUSHA Mitsuru; NAKAZAWA Kazuhiro; NUMATA Kenji; SAKAI Shin-ichiro; SETO Naoki; TAKASHIMA Takeshi; TANAKA Takahiro; DECIGO Working Group the
TRANSACTIONS OF THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES, SPACE TECHNOLOGY JAPAN, THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES, 8, 27, Po_4_1-Po_4_6, 2010, A space gravitational wave antenna, DECIGO (DECI-hertz interferometer Gravitational wave Observatory) will provide fruitful insights into the universe, particularly on dark energy, the formation mechanism of supermassive black holes, and the inflation of the universe. In the current pre-conceptual design, DECIGO will be comprised of 4 interferometer units; each interferometer unit will be realized by formation flight of three drag-free spacecraft with 1000 km separation. Since DECIGO will be an extremely challenging mission with high-precision formation flight, it is important to increase the technical feasibility before its planned launch in 2024. Thus, we are planning two milestone missions. DECIGO pathfinder (DPF) is the first milestone mission for DECIGO, and key components for DPF are being tested on ground and in orbit. In this article, we review the conceptual design and current status of DECIGO and DPF.
English

Passively Q-switched Nd:YAG ceramic microchip laser with azimuthally polarized output
J. -L. Li; D. Lin; L. -X. Zhong; K. Ueda; A. Shirakawa; M. Musha; W. -B. Chen
LASER PHYSICS LETTERS, IOP PUBLISHING LTD, 6, 10, 711-714, Oct. 2009, Peer-reviwed, A passively-Q-switched neodymium-doped yttrium. aluminum garnet (Nd:YAG) ceramic microchip, laser was demonstrated to emit azimuthally polarized beam bus using a chromium-doped YAG (Cr4+:YAG) crystal as saturable absorber and a multilayer concentric subwavelength grating as polarization-selective output coupler. The laser's output power reached 512 mW with an initial slope efficiency of nearly 60%, and the pulse bad 1.15-kW peak power with 40-ns duration and 11-kHz repetition rate at 3.9-W absorbed pump power. The laser beam's polarization degree was 97.6%. The thermal lensing effect in Nd:YAG microchip remained as a problem: to be solved.
[GRAPHICS]
Averaged output power of the laser as a function of the absorbed pump power (c) 2009 by Astro Ltd. Published exclusively by WILEY-VCH Verlag GmbH & Co. KGaA
Scientific journal, English

Recent Progress of the RF and Timing System of XFEL/SPring-8
H.Maesaka; T.Ohshima; N.Hosoda; S.Matsubara; K.Tamasaku; T.Fukui; Y.Otake; M.Musha
Proc. of ICALEPCS 2009, TUC002, Oct. 2009, Peer-reviwed
International conference proceedings, English

Measuring the frequency of a Sr optical lattice clock using a 120 km coherent optical transfer
F. -L. Hong; M. Musha; M. Takamoto; H. Inaba; S. Yanagimachi; A. Takamizawa; K. Watabe; T. Ikegami; M. Imae; Y. Fujii; M. Amemiya; K. Nakagawa; K. Ueda; H. Katori
OPTICS LETTERS, OPTICAL SOC AMER, 34, 5, 692-694, Mar. 2009, Peer-reviwed, We demonstrate a precision frequency measurement using a phase-stabilized 120 km optical fiber link over a physical distance of 50 km. The transition frequency of the (87)Sr optical lattice clock at the University of Tokyo is measured to be 429228004229874.1(2.4) Hz referenced to international atomic time. The results demonstrate the excellent functions of the intercity optical fiber link and the great potential of optical lattice clocks for use in the redefinition of the second. (C) 2009 Optical Society of America
Scientific journal, English

Developments of the light source for DECIGO
武者満
The Review of Laser Engineering, 37, 2, 96-101, Feb. 2009, Peer-reviwed
Research society, Japanese

Frequency Measurement of a Sr Optical Lattice Clock Using a Coherent Optical Link over a 120-km Fiber
F. -L. Hong; M. Musha; M. Takamoto; H. Inaba; S. Yanagimachi; A. Takamizawa; K. Watabe; T. Ikegami; M. Imae; Y. Fujii; M. Amemiya; K. Nakagawa; K. Ueda; H. Katori
2009 CONFERENCE ON LASERS AND ELECTRO-OPTICS AND QUANTUM ELECTRONICS AND LASER SCIENCE CONFERENCE (CLEO/QELS 2009), VOLS 1-5, IEEE, CMB2, 305-+, 2009, Peer-reviwed, We demonstrate a precision frequency measurement using a phase-stabilized 120-km optical fiber link over a physical distance of 50 km. The absolute frequency of the Sr-87 optical lattice clock is measured to be 429228004229874.1(2.4) Hz. (C)2009 Optical Society of America
International conference proceedings, English

Radially polarized and pulsed output from passively Q-switched Nd:YAG ceramic microchip laser
Jian-lang Li; Ken-ichi Ueda; Mitsuru Musha; Lan-xiang Zhong; Akira Shirakawa
OPTICS LETTERS, OPTICAL SOC AMER, 33, 22, 2686-2688, Nov. 2008, Peer-reviwed, For the first time, to the best of our knowledge, a radially polarized laser pulse was produced from a passively Q-switched Nd:YAG ceramic microchip laser with a piece of Cr(4+):YAG crystal as the saturable absorber and multilayer concentric subwavelength grating as the polarization-selective output coupler. The averaged laser power reached 450 mW with a slope efficiency of 30.2%. The laser pulse had a maximum peak power of 759 W, a minimum pulse duration of 86 ns, and a 6.7 kHz repetition rate at 3.7 W absorbed pump power. The polarization degree of the radially polarized pulse was measured to be as high as 97.4%. Such a radially polarized laser pulse with a high peak power and a short width is important to numerous applications such as metal cutting. (C) 2008 Optical Society of America
Scientific journal, English

Coherent optical frequency transfer over 50-km physical distance using a 120-km-long installed telecom fiber network
Mitsuru Musha; Feng-Lei Hong; Ken'ichi Nakagawa; Ken-ichi Ueda
OPTICS EXPRESS, OPTICAL SOC AMER, 16, 21, 16459-16466, Oct. 2008, Peer-reviwed, Optical frequency at 1542 nm was coherently transferred over a 120-km-long installed telecom fiber network between two cities (Tsukuba and Tokyo) in Japan separated by more than 50 km. The phase noise induced by the fiber length fluctuations was actively reduced by using a fiber stretcher and an acousto-optic modulator. The fractional frequency instability of the one-way transmitted light was reduced down to less than 8.0 x 10(-16) at an averaging time of 1s, which is limited by the theoretical limit deduced from the length and the intrinsic noise of the fiber. (c) 2008 Optical Society of America
Scientific journal, English

Low Level RF and Timing System for XFEL/SPRING-8
T.Oshima; N.Hosoda; H.Maesaka; K.Tamasaku; M.Musha; Y.Otake
Proc of XXIV Linear Accelerator Conference, ***, Oct. 2008, Peer-reviwed
International conference proceedings, English

Development of the Optical Timing and rf Distribution Systemfor XFEL/SPring-8
Y.Otake; K.Tamasaku; K.Imai; MKourogi; N.Hosoda; M.Kitamura; H.Maesaka; T.Ohshima; M.Musha
Proc. of 30th International Conference on Free Electron Laser, TU/PPH046, Aug. 2008, Peer-reviwed
International conference proceedings, English

Precision Optical Carrier Transfer over 110km
Mitsuru Musha; Feng-Lei Hong; Ken'ichi Nakagawa; Ken-ichi Ueda
URSI General Assembly 2008, A02.3, Aug. 2008, Peer-reviwed
International conference proceedings, English

Efficient excitations of radially and azimuthally polarized Nd3+: YAG ceramic microchip laser by use of subwavelength multilayer concentric gratings composed of Nb2O5/SiO2
Jian-lang Li; Ken-ichi Ueda; Lan-xiang Zhong; Mitsuru Musha; Akira Shirakawa; Takashi Sato
OPTICS EXPRESS, OPTICAL SOC AMER, 16, 14, 10841-10848, Jul. 2008, Peer-reviwed, Cylindrical vector beams were produced from laser diode end-pumped Nd:YAG ceramic microchip laser by use of two types of subwavelength multilayer gratings as the axisymmetric-polarization output couplers respectively. The grating mirrors are composed of high- and low-refractive-index (Nb2O5/SiO2) layers alternately while each layer is shaped into triangle and concentric corrugations. For radially polarized laser output, the beam power reached 610mW with a polarization extinction ratio ( PER) of 61: 1 and a slope efficiency of 68.2%; for azimuthally polarized laser output, the beam power reached 626mW with a PER of 58: 1 and a slope efficiency of 47.6%. In both cases, the laser beams had near-diffraction limited quality. Small differences of beam power, PER and slope efficiency between radially and azimuthally polarized laser outputs were not critical, and could be minimized by further optimized adjustment to laser cavity and the reflectances of respective grating mirrors. The results manifested, by use of the photonic crystal gratings mirrors and end-pumped microchip laser configuration, CVBs can be generated efficiently with high modal symmetry and polarization purity. (C) 2008 Optical Society of America.
Scientific journal, English

Coherent optical transfer via 110-km urban fiber network for freqquency measurement of 87Sr optical lattice clock
M.Musha; F-L. Hong; M.Takamoto; H. Inaba; S. Yanagimachi; A.Takayaagi; K.Watabe; T.Ikegami; Michito I.Yasuhisa; Y.Fujii; M.Amemiya; K.Nakagawa; K.Ueda; H.Katori
CPEM2008, ThP26, Jun. 2008, Peer-reviwed
International conference proceedings, English

Robust and precision length correction of the long optical fiber for ddissemination of frequency standards
Mitsuru Musha; Ken'ich Nakagawa; Ken-ichi Ueda
Proc. of CLEO2008, CML3, May 2008, Peer-reviwed
International conference proceedings, English

24pZW-2 干渉計型重力波検出器TAMA300開発の現状XX(干渉計開発)(重力波,宇宙線・宇宙物理領域)
新井 宏二; 石崎 秀晴; 中川 憲保; 高森 昭光; Bertolini A; DeSalvo R; 佐藤 修一; 麻生 洋一; 阿久津 智忠; 常定 芳基; 長野 重夫; 辰巳 大輔; 安東 正樹; 三代木 伸二; 森脇 成典; 神田 展行; 武者 満; 藤本 眞克; 川村 静児; 三尾 典克; 大橋 正健; 黒田 和明; 高橋 竜太郎; 坪野 公夫; TAMA Conaboration; 和泉 究; 我妻 一博; 荒瀬 勇太; 若林 野花; 福嶋 美津広; 山崎 利孝
一般社団法人 日本物理学会 日本物理学会講演概要集, The Physical Society of Japan (JPS), 63, 0, 112-112, 2008, Peer-reviwed
Scientific journal, English

Fiber length stabilization system for Long-Baseline Phased-array Radio Telescopes (ALMA)
Mitsuru Musha; Ken'ichi Nakagawa; Ken-ichi Ueda; Masato Ishiguiro; Akitoshi Ueda
2008 CONFERENCE ON LASERS AND ELECTRO-OPTICS & QUANTUM ELECTRONICS AND LASER SCIENCE CONFERENCE, VOLS 1-9, IEEE, 610-+, 2008, Peer-reviwed, We've developed local oscillator dissemination system for ALMA. The high-purity 120GHz local oscillator was delivered as a heterodyne beat signal over 25 km through length corrected optical fibers with phase fluctuation of 10(-2) radian.
International conference proceedings, English

光ファイバを用いた高精度周波数配信
武者満
光アライアンス, 日本工業出版, 19, 9, 16-20, 2008
Research society, Japanese

39-mW annular excitation of ytterbiurn fiber laser with radial polarization
J. -L. Li; K. -I. Ueda; A. Shirakawa; M. Musha; L. -X. Zhong; Z. -M. Zhang
LASER PHYSICS LETTERS, IOP PUBLISHING LTD, 4, 11, 814-818, Nov. 2007, Peer-reviwed, An efficient radial-polarization Yb-fiber laser with an intracavity Brewster axicon is demonstrated. The fraction of ASE at low pumping and parasitical oscillation are minimized by adopting bidirectional pumping and angle-polisbed fiber end. So far, except for the improvement in polarization purity and cylindrical symmetry of output beam, 39-mW output power is obtained at 460-mW launched pump power with 13.8% slope efficiency. And also a new type of low-V-parameter multi-mode gain fiber with doughnut concentration distribution of active ions in fiber core profile is predicted to be promising in improving the laser performance further.
Scientific journal, English

Timing and LLRF system of Japanese X-FEL to realize a few tenth of femto-second stability
Y.Otake; T.Oshima; N.Hosoda; H.Maesaka; T.Fukui; T.Ohata; M.Musha; K.Tamasaku; M.Kitamura; K.Imai.M.Kourogi; T.Shintake
Proc. of ICALEPCS 2007, 1302, Oct. 2007, Peer-reviwed
International conference proceedings, English

光コムを用いたレーザーの高精度周波数制御技術
武者満
プラズマ・核融合学会誌, 83, 8, 698, Aug. 2007
Research society, Japanese

Converging-axicon-based radially polarized ytterbium fiber laser and evidence on the mode profile inside the gain fiber
Jian-lang Li; Ken-ichi Ueda; Mitsuru Musha; Akira Shirakawa; Zhi-ming Zhang
OPTICS LETTERS, OPTICAL SOC AMER, 32, 11, 1360-1362, Jun. 2007, Peer-reviwed, The radially polarized mode is achieved from an active Yb fiber by utilizing of an intracavity converging axicon, where the axicon acts as a TM01 mode selector based on not only its Brewster convex surface but also the distance between its vertex and plane output coupler. The polarization state of the annular laser beam is checked by using a home-made eight-hole aperture. Furthermore, an uncoated plane glass plate is inserted into the cavity, and the reflected beam points to the existence of an annular lasing mode inside the gain fiber. The issues for developing high-power radially polarized fiber lasers also are considered. (c) 2007 Optical Society of America.
Scientific journal, English

Practical optical frequency measurement system around 1.5 mu m based on an acetylene-stabilized laser-locked optical frequency comb
Mitsuru Musha; Yosuke Tamura; Ken'ichi Nakagawa; Ken-ichi Ueda
OPTICS COMMUNICATIONS, ELSEVIER SCIENCE BV, 272, 1, 211-216, Apr. 2007, Peer-reviwed, We have developed a practical and precise frequency measurement system at 1.5 mu m telecommunication band. An electro-optic-modulator based optical frequency comb is phase-locked to a dither-free acetylene-stabilized laser to realize an optical frequency comb with frequency uncertainty of 10 kHz (5 x 10(-11)) and the linewidth of 15 kHz. The present frequency comb can be also used as an optical frequency reference grid defined by ITU-T (International Telecommunication Union, Telecommunication Standardization Sector). Using the present frequency measurement system, we have demonstrated the first optical frequency measurement of (CO)-C-12-O-16 overtone absorption lines around 1.56 mu m with the uncertainty of lower than 900 kHz. (c) 2006 Elsevier B.V. All rights reserved.
Scientific journal, English

Transient temperature profile in the gain medium of CW- and end-pumped passively Q-switched microchip laser
Jianlang Li; Jun Dong; Musha Mitsurua; Akira Shirakawa; Ken-ichi Ueda
OPTICS COMMUNICATIONS, ELSEVIER SCIENCE BV, 270, 1, 63-67, Feb. 2007, Peer-reviwed, The transient temperature profile in CW- and end-pumped passively Q-switched (PQS) microchip laser is investigated qualitatively by treating the population inversion (thereby the thermal load) as the sawtooth function of the time. The numerical results reveal not only the dynamics of thermal buildup, but also the dependence of the quasi-steady-state temperature rise and the repetitively oscillatory amplitude on the incident pump power and the pulse repetition rate of PQS laser. The abruptly ascending branch of the repetitive temperature oscillation is synchronized with the pulsing stage of PQS laser. As the result, the abrupt temperature transition during the pulsing stage would introduce the fluctuation into the PQS pulse parameters (pulse energy, pulse width, and peak power) via temperature-dependent stimulated emission and thermal lensing effect. (c) 2006 Elsevier B.V. All rights reserved.
Scientific journal, English

21pZH-5 干渉計型重力波検出器TAMA300開発の現状 XVIII : 干渉計開発(21pZH 重力波,宇宙線・宇宙物理領域)
新井 宏二; 高森 昭光; Bertolini A; DeSalvo R; 佐藤 修一; 麻生 洋一; 阿久津 智忠; 常定 芳基; 長野 重夫; 安東 正樹; 三代木 伸二; 辰巳 大輔; 森脇 成典; 神田 展行; 武者 満; 藤本 眞克; 川村 静児; 三尾 典克; 大橋 正健; 黒田 和明; 坪野 公夫; TAMA Collaboration; 和泉 究; 高橋 竜太郎; 我妻 一博; 荒瀬 勇太; 福嶋 美津広; 山崎 利孝; 石崎 秀晴
一般社団法人 日本物理学会 日本物理学会講演概要集, The Physical Society of Japan (JPS), 62, 0, 100-100, 2007, Peer-reviwed
Scientific journal, English

27pSG-6 干渉計型重力波検出器TAMA300開発の現状XIII : 干渉計開発(27pSG 重力波,宇宙線・宇宙物理領域)
新井 宏二; Bertolini A; DeSalvo R; 佐藤 修一; 麻生 洋一; 阿久津 智忠; 常定 芳基; 長野 重夫; 安東 正樹; 三代木 伸二; 森脇 成典; 辰巳 大輔; 神田 展行; 武者 満; 藤本 眞克; 川村 静児; 三尾 典克; 大橋 正健; 黒田 和明; 坪野 公夫; TAMA Collaboration; 高橋 竜太郎; 中川 憲保; 我妻 一博; 荒瀬 勇太; 福嶋 美津広; 山崎 利孝; 高森 昭光
一般社団法人 日本物理学会 日本物理学会講演概要集, The Physical Society of Japan (JPS), 62, 0, 109-109, 2007, Peer-reviwed
Scientific journal, English

21pZH-2 干渉計型重力波検出器TAMA300開発の現状 XV : 低周波防振装置2(21pZH 重力波,宇宙線・宇宙物理領域)
我妻 一博; 高森 昭光; Bertolini A; DeSalvo R; 佐藤 修一; 麻生 洋一; 阿久津 智忠; 常定 芳基; 長野 重夫; 安東 正樹; 三代木 伸二; 高橋 竜太郎; 森脇 成典; 神田 履行; 武者 満; 藤本 眞克; 川村 静児; 三尾 典克; 大橋 正健; 黒田 和明; 坪野 公夫; TAMA Collaboration; 荒瀬 勇太; 福嶋 美津広; 山崎 利孝; 石崎 秀晴; 新井 宏二; 辰巳 大輔; 和泉 究
一般社団法人 日本物理学会 日本物理学会講演概要集, 62, 0, 2007, Peer-reviwed
Scientific journal, English

Self-pulsing dynamics of ytterbium-doped fiber laser with pump-bypassed cavity
J. Li; K. -I. Ueda; M. Musha; A. Shirakawa; L. Zhong
APPLIED PHYSICS B-LASERS AND OPTICS, SPRINGER, 85, 4, 565-569, Dec. 2006, Peer-reviwed, The pump-bypassed laser cavity is suggested as a suitable configuration for investigating the self-pulsing instability in fibre laser. Such arrangement allows access to the residual pump light, which acts as a probe of the intra-cavity dynamics and reflects the inversion variation along the whole gain fibre. We check this method with ytterbium-doped fibre (YDF) laser. The experimental results in original cavity and modified cavity are offered in detail respectively. The analyses of both the temporal traces of the residual pump and laser signal manifest that the various instabilities in YDF laser are associated with the interactions among stimulated emission, pump and/or reabsorption, dependently on the inversion level and also the intensities of the pump and laser intra-cavity signal.
Scientific journal, English

Dual-wavelength-switching operation based on optical bistability in pump-bypassed ytterbium-doped fiber laser
J. -L. Li; M. Musha; A. Shirakawa; K. -I Ueda; L. -X. Zhong
APPLIED PHYSICS B-LASERS AND OPTICS, SPRINGER, 85, 4, 545-548, Dec. 2006, Peer-reviwed, The bistable feature of residual pump in a pump-bypassed Yb-doped fiber laser offers the potential to pump Er/Yb co-doped fiber in a bifurcated cavity for the lasing of the 1537 nm line. The results of our proof-of-concept demonstration show that the oscillations at 1040 nm and 1537 nm are operated in the wavelength-switching mode, and this suggests that the combination of optical bistability in a pump-bypassed fiber laser cavity with a bifurcated cavity could be one simple and efficient method for switchable dual-wavelength operation.
Scientific journal, English

Generation of radially polarized mode in Yb fiber laser by using a dual conical prism
Jian-lang Li; Ken-ichi Ueda; Mitsuru Musha; Akira Shirakawa; Lan-xiang Zhong
OPTICS LETTERS, OPTICAL SOC AMER, 31, 20, 2969-2971, Oct. 2006, Peer-reviwed, For the first time to our knowledge, a radially polarized beam is generated in an Yb-doped multimode double-clad fiber laser by using an intracavity dual conical prism. Up to 6.2 mW of output power is obtained from a 2 m long gain fiber with 7.4% slope efficiency. This research opens a new window to obtaining a radially polarized beam directly from an active fiber. (c) 2006 Optical Society of America.
Scientific journal, English

Maximum value of the pulse energy of a passively Q-switched laser as a function of the pump power
Jianlang Li; Ken-ichi Ueda; Jun Dong; Mitsuru Musha; Akira Shirakawa
APPLIED OPTICS, OPTICAL SOC AMER, 45, 21, 5377-5384, Jul. 2006, Peer-reviwed, The finite recovery time T-s of the bleached absorber is presented as one of the possible mechanisms accounting for the increase-maximum-decrease in pulse energy E with the pumping rate W-p in cw-pumped passively Q-switched solid-state lasers. by analytically evaluating the sign of the derivative partial derivative E/partial derivative W-p. The results show that. in the low punipinie (T > T-s, T is the interpulse period). the initial repopulation density n, remains constant. the final population density n(i) decreases with W-p. and this results in a monotonic increase of E with W-p. In the high pump regime (T < T-s). n, decreases but n(i) remains the same with W-P; this results in a monotonic decrease of E with W-p. At the critical region (T approximate to T), E reaches its maximum value. A cw-pumped Yb:YAG laser passively Q switched by a Cr4-:YAG absorber is demonstrated to confirm this model. The theoretical model is also applied to the analysis of three previously reported passive Q switching solid-state [Nd:GdVO4, Nd-:LaSc3(BO3)(4) (Nd-:LSB), and Nd:YAG] lasers experiments. (c) 2006 Optical Society of America.
Scientific journal, English

Gravitational Wave Detection by Using Long-Baseline Laser Interferometer
Mitsuru Musha
The Review of Laser Engineering, 34, 5, 382-385, May 2006
Research society, Japanese

Residual pump light as a probe of self-pulsing instability in an ytterbium-doped fiber laser
JL Li; K Ueda; M Musha; A Shirakawa
OPTICS LETTERS, OPTICAL SOC AMER, 31, 10, 1450-1452, May 2006, Peer-reviwed, Self-pulsing instability in the ytterbium-doped fiber (YDF) laser is investigated with the pump-bypassed cavity configuration. The residual pump light acts as a probe of the intracavity dynamics, and the temporal behavior of the light shows correlations with the self-mode locking instability in the original cavity and the sustained self-pulsing instability in the modified cavity of the YDF laser. The results suggest that the interactions among stimulated emission, pump absorption and/or reabsorption could account for self-pulsing instability in the YDF laser. The pump-bypassed laser cavity configuration can be used to investigate the instabilities of various kinds of fiber lasers. (c) 2006 Optical Society of America.
Scientific journal, English

The Japanese space gravitational wave antenna—DECIGO
Seiji Kawamura; Takashi Nakamura; Masaki Ando; Naoki Seto; Kimio Tsubono; Kenji Numata; Ryuichi Takahashi; Shigeo Nagano; Takehiko Ishikawa; Mitsuru Musha; Ken-ichi Ueda; Takashi Sato; Mizuhiko Hosokawa; Kazuhiro Agatsuma; Tomotada Akutsu; Koh-suke Aoyanagi; Koji Arai; Akito Araya; Hideki Asada; Yoichi Aso; Takeshi Chiba; Toshikazu Ebisuzaki; Yoshiharu Eriguchi; Masa-Katsu Fujimoto; Mitsuhiro Fukushima; Toshifumi Futamase; Katsuhiko Ganzu; Tomohiro Harada; Tatsuaki Hashimoto; Kazuhiro Hayama; Wataru Hikida; Yoshiaki Himemoto; Hisashi Hirabayashi; Takashi Hiramatsu; Kiyotomo Ichiki; Takeshi Ikegami; Kaiki T Inoue; Kunihito Ioka; Koji Ishidoshiro; Yousuke Itoh; Shogo Kamagasako; Nobuyuki Kanda; Nobuki Kawashima; Hiroyuki Kirihara; Kenta Kiuchi; Shiho Kobayashi; Kazunori Kohri; Yasufumi Kojima; Keiko Kokeyama; Yoshihide Kozai; Hideaki Kudoh; Hiroo Kunimori; Kazuaki Kuroda; Kei-ichi Maeda; Hideo Matsuhara; Yasushi Mino; Osamu Miyakawa; Shinji Miyoki; Hiromi Mizusawa; Toshiyuki Morisawa; Shinji Mukohyama; Isao Naito; Noriyasu Nakagawa; Kouji Nakamura; Hiroyuki Nakano; Kenichi Nakao; Atsushi Nishizawa; Yoshito Niwa; Choetsu Nozawa; Masatake Ohashi; Naoko Ohishi; Masashi Ohkawa; Akira Okutomi; Kenichi Oohara; Norichika Sago; Motoyuki Saijo; Masaaki Sakagami; Shihori Sakata; Misao Sasaki; Shuichi Sato; Masaru Shibata; Hisaaki Shinkai; Kentaro Somiya; Hajime Sotani; Naoshi Sugiyama; Hideyuki Tagoshi; Tadayuki Takahashi; Hirotaka Takahashi; Ryutaro Takahashi; Tadashi Takano; Takahiro Tanaka; Keisuke Taniguchi; Atsushi Taruya; Hiroyuki Tashiro; Masao Tokunari; Shinji Tsujikawa; Yoshiki Tsunesada; Kazuhiro Yamamoto; Toshitaka Yamazaki; Jun'ichi Yokoyama; Chul-Moon Yoo; Shijun Yoshida; Taizoh Yoshino
Classical and Quantum Gravity, IOP Publishing, 23, 8, S125-S131, 21 Apr. 2006, Peer-reviwed
Scientific journal

Strong optical bistability in ytterbium-doped fibre laser with reabsorption
JL Li; M Musha; A Shirakawa; KI Ueda; L Zhong
ELECTRONICS LETTERS, INSTITUTION ENGINEERING TECHNOLOGY-IET, 42, 8, 449-450, Apr. 2006, Peer-reviwed, The strong optical bistability in a ytterbium-doped fibre (YDF) laser is demonstrated, which is due to the saturable absorption of the unpumped YDF stage. The bistable regions of both the signal output and residual pump light are 320 mW within an antiphase manner with respect to each other. The signal output and residual pump light also exhibit self-pulsing instability. A bifurcated laser cavity configuration for switchable dual-wavelength generation is predicted based on the optical bistability of the residual pump power.
Scientific journal, English

Developments of a fibre-MOPA system for the light source of the gravitational wave antenna
Mitsuru Musha; Jun-ichi Miura; Ken'ichi Nakaawa; Kne-ichi Ueda
Classical and Quantum Gravity, 23, 287-292, Mar. 2006, Peer-reviwed
Scientific journal, English

Robust and precise length stabilization of a 25-km long optical fiber using an optical interferometric method with a digital phase-frequency discriminator
Mitsuru Musha; Yohei Sato; Ken'ichi Nakagawa; Ken-ichi Ueda; Akitoshi Ueda; Masato Ishiguro
Applied Physics B, 82, 555-559, Feb. 2006, Peer-reviwed
Scientific journal, English

20pSG-2 干渉計型重力波検出器TAMA300開発の現状VIII : 低周波防振装置(20pSG 重力波,宇宙線・宇宙物理領域)
我妻 一博; 高森 昭光; Bertolini A; DeSalvo R; 佐藤 修一; 阿久津 智忠; 常定 芳基; 長野 重夫; 安東 正樹; 三代木 伸二; 森脇 成典; 高橋 竜太郎; 神田 展行; 武者 満; 藤本 眞克; 川村 静児; 三尾 典克; 大橋 正健; 黒田 和明; 坪野 公夫; TAMA Collaboration; 荒瀬 勇太; 辰巳 大輔; 麻生 洋一; 新井 宏二; 中川 憲保; 福嶋 美津広; 山崎 利孝
一般社団法人 日本物理学会 日本物理学会講演概要集, The Physical Society of Japan (JPS), 61, 0, 56-56, 2006, Peer-reviwed
Scientific journal, English

27aTG-2 干渉計型重力波検出器TAMA300開発の現状V : 干渉計開発(27aTG 重力波,宇宙線・宇宙物理領域)
新井 宏二; 高森 昭光; 飯田 幸美; Bertolini A; DeSalvo R; 三代木 伸二; 長野 重夫; 安東 正樹; 森脇 成典; 神田 展行; 武者 満; 佐藤 修一; 三尾 典克; 川村 静児; 藤本 眞克; 坪野 公夫; 大橋 正健; 黒田 和明; TAMA Collaboration; 高橋 竜太郎; 阿久津 智忠; 中川 憲保; 辰巳 大輔; 常定 芳基; 福嶋 美津広; 山崎 利孝
一般社団法人 日本物理学会 日本物理学会講演概要集, The Physical Society of Japan (JPS), 61, 0, 85-85, 2006, Peer-reviwed
Scientific journal, English

Results of the search for inspiraling compact star binaries from TAMA300's observation in 2000-2004
T.Akutsu; T.Akutsu; M.Ando; K.Arai; A.Aray; Y.Aso; M.Musha et
Physical Review D, The American Physical Society, 74, 12, 122002, 2006, Peer-reviwed, We analyze the data of the TAMA300 detector to search for gravitational waves from inspiraling compact star binaries with masses of the component stars in the range 1M-3M. In this analysis, 2705 hours of data, taken during the years 2000-2004, are used for the event search. We combine the results of different observation runs, and obtain a single upper limit on the rate of the coalescence of compact binaries in our Galaxy of 20 per year at a 90% confidence level. In this upper limit, the effects of various systematic errors such as the uncertainty of the background estimation and the calibration of the detector's sensitivity are included.
Scientific journal, English

Switchable lasing of 1040 and 1537-nm lines based on the optical bistability in the pump-bypassed ytterbium-doped fiber laser
Jianlang Li; Mitsuru Musha; Akira Shirakawa; Ken-ichi Ueda
PHOTONIC DEVICES AND ALGORITHMS FOR COMPUTING VIII, SPIE-INT SOC OPTICAL ENGINEERING, 6310, 2006, Peer-reviwed, Lots of attention has been paid to the optical bistability in fiber optical because its potential application in optical information processing and fiber optical communication. Recently the optical bistability in erbium-doped active fiber induced by the nonlinear absorption of the fiber has been investigated. In this paper, we demonstrated the strong optical bistability in the ytterbium-doped fiber laser with the pump-bypassed cavity configuration. In this original configuration, the fiber laser is divided into the gain stage and absorption stage by a WDM. As the function of incident pump power, both the 976nm residual pump intensity and the 1040nm laser signal of this laser exhibit similar to 320mW-wide optical bistabilities in an antiphase manner with respect to each other. Further the residual pump power is directed to pump the second Er and Yb co-doped fiber laser cavity to generate the lasing at 1537mn. As a result of the optical bistability in the residual pump, the lasings of 1040nm and 1537nm are switchable between each other. Worthwhile to point out, these two wavelengths are located in the two wavelength windows applicable for the free-space laser communications, respectively. Therefore the switchable 1040 and 1537nm source by combining the bistable feature of Yb fiber laser with the hybrid cavity configuration (pump-bypassed cavity plus the bifurcated cavity could have important application at this aspect.
International conference proceedings, English

Power scaling of Tm3+ stop doped ZBLAN blue upconversion fiber lasers: modeling and experiments
G Qin; S Huang; Y Feng; A Shirakawa; M Musha; KI Ueda
APPLIED PHYSICS B-LASERS AND OPTICS, SPRINGER, 82, 1, 65-70, Jan. 2006, Peer-reviwed, Power scaling of Tm(3+)s doped ZBLAN blue upconversion fiber lasers was investigated by a simple model. Based on our experimental results on blue fiber lasers, we discuss the effects of photodegradation and photocuring, fiber length, the reflectivity of the coupler mirror and fiber core diameter on further enhancement of blue fiber laser, respectively. The optimal parameters (including fiber length, fiber core diameter and the reflectivity of the coupler mirror) for the operation of high power (> 1 W) blue fiber laser were presented through simple numerical simulations, which are valuable for the future design of high power blue upconversion fiber laser.
Scientific journal, English

1083 nm single frequency ytterbium doped fiber laser
S Huang; Y Feng; J Dong; A Shirakawa; M Musha; K Ueda
LASER PHYSICS LETTERS, IOP PUBLISHING LTD, 2, 10, 498-501, Oct. 2005, Peer-reviwed, Single frequency 1083 nm ytterbium fiber laser was demonstrated by introducing loop mirror filter and polarization controller in linear laser cavity. The loop mirror with unpumped ytterbium fiber as a narrow bandwidth filter discriminated and selected laser longitudinal modes efficiently. Spatial hole burning effect was restrained by adjusting polarization controller appropriately. The laser linewidth was about 2 KHz. Output power up to 14 mW were obtained under the launched pump power of 100 mW at 976 nm, the corresponding optical-optical conversion efficiency was 14%, the slope efficiency was 18%a. The measurement of RIN and power stability indicated the stable operation of the laser.
Scientific journal, English

Single frequency 1083nm ytterbium doped fiber master oscillator power amplifier laser
SH Huang; GS Qin; A Shirakawa; M Musha; K Ueda
OPTICS EXPRESS, OPTICAL SOC AMER, 13, 18, 7113-7117, Sep. 2005, Peer-reviwed, Single frequency 1083nm ytterbium fiber master oscillator power amplifier system was demonstrated. The oscillator was a linear fiber cavity with loop mirror filter and polarization controller. The loop mirror with unpumped ytterbium fiber as a narrow bandwidth filter discriminated and selected laser longitudinal modes efficiently. Spatial hole burning effect was restrained partially by adjusting polarization controller appropriately in the linear cavity. The amplifier was 5 m ytterbium doped fiber pumped by 976nm pigtail coupled laser diode. The linewidth of the single frequency laser was about 2 KHz. Output power up to 177 mW was produced under the launched pump power of 332 mW. (c) 2005 Optical Society of America
Scientific journal, English

Developments of a fiber-MOPA system for the light source of the gravitational wave antenna
J.Miura; M.Musha; K.Nakaawa; K.Ueda
Proc. of AMALDI6, aa, Aug. 2005, Peer-reviwed
International conference proceedings, English

Stable laser-diode pumped microchip sub-nanosecond Cr,Yb : YAG self-Q-switched laser
J Dong; A Shirakawa; S Huang; Y Feng; K Takaichi; M Musha; K Ueda; AA Kaminskii
LASER PHYSICS LETTERS, IOP PUBLISHING LTD, 2, 8, 387-391, Aug. 2005, Peer-reviwed, Near-diffraction-limited longitudinal multimode self-Q-switched microchip Cr,Yb:YAG laser is obtained by using of a laser diode as a pump source at room temperature without cooling Cr,Yb:YAG sample. The output Q-switched traces are very stable, and the slope efficiency is as high as 18.5%. Laser pulses with 33.5-mu J pulse energy and 400-ps pulse duration were achieved which results in over 53 kW peak power at repetition rate of 6.6 kHz. The effect of the absorbed pump power on the laser characterization and laser spectrum are addressed in details. The number of the longitudinal laser modes increases with the absorbed pump power.
Scientific journal, English

Single-frequency fiber laser from linear cavity with loop mirror filter and dual-cascaded FBGs
SH Huang; GS Qin; Y Feng; A Shirakawa; M Musha; KI Ueda
IEEE PHOTONICS TECHNOLOGY LETTERS, IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 17, 6, 1169-1171, Jun. 2005, Peer-reviwed, A single-frequency ytterbium fiber laser was demonstrated by introducing a loop mirror filter, a polarization controller (PC), and dual-cascaded fiber Bragg gratings (FBGs) in linear laser cavity. The loop mirror with unpumped ytterbium fiber as a narrow bandwidth filter discriminated and selected laser longitudinal modes efficiently. The spatial hole burning effect was restrained by adjusting PC appropriately. Dual closely cascaded FBGs as the output coupler, acting as an etalon, expanded the operation range of single frequency. Output power up to 18 mW at 1064 nm were obtained under the launched pump power of 107 mW at 976 nm, the optical-optical conversion efficiency was about 16.8%; the slope efficiency was about 20%.
Scientific journal, English

Photodegradation and photocuring in the operation of a blue upconversion fiber laser
G Qin; S Huang; Y Feng; A Shirakawa; M Musha; KI Ueda
JOURNAL OF APPLIED PHYSICS, AMER INST PHYSICS, 97, 12, 126108, Jun. 2005, Peer-reviwed, Photodegradation and photocuring effects were investigated in the operation of a Tm3+-doped blue upconversion fiber laser. Our experimental results indicate that a competition between photodegradation and photocuring greatly affects the maximum output power of a blue upconversion fiber laser. (c) 2005 American Institute of Physics.
Scientific journal, English

Blue up-conversion fibre laser pumped by a 1120-nm Raman fibre laser
GS Qin; SH Huang; Y Feng; A Shirakawa; M Musha; K Ueda
CHINESE PHYSICS LETTERS, CHINESE PHYSICAL SOC, 22, 5, 1140-1143, May 2005, Peer-reviwed, A Tm3+ -doped ZrF4-BaF2-LaF3-AlF3-NaF (ZBLAN) fibre up-conversion laser pumped by Raman fibre laser is demonstrated with blue output power levels up to 116mW. For the output mirror with 80% reflectivity, the slope efficiency is about 15%, the optical- to-optical conversion efficiency is 11%, and the maximum un-saturated output power is 116mW. For 60% reflectivity, the slope efficiency is about 18% and the optical-to-optical conversion efficiency is 12%, whilst the maximum saturated output power is about 80 mW due to the existence of photo-degradation effect in Tm3+ doped ZBLAN glass fibre.
Scientific journal, English

Modulation-free acetylene-stabilized lasers at 1542 nm using modulation transfer spectroscopy
K. Nakagawa; Y. Sato; M. Musha; K. Ueda
Applied Physics B: Lasers and Optics, 80, 4-5, 479-482, Apr. 2005, Peer-reviwed, We report frequency stabilization of diode lasers using modulation transfer spectroscopy of an acetylene transition (13C2H 2, ν1+ν3, P(16)) at 1542 nm. We realize modulation-free acetylene-stabilized lasers with a frequency stability of about 10-11 and an absolute frequency accuracy of about 20 kHz. © Springer-Verlag 2005.
Scientific journal, English

Large-mode-area erbium-ytterbium-doped photonic-crystal fiber amplifier for high-energy femtosecond pulses at 1.55 mu m
A Shirakawa; J Ota; M Musha; K Nakagawa; K Ueda; Folkenberg, JR; J Broeng
OPTICS EXPRESS, OPTICAL SOC AMER, 13, 4, 1221-1227, Feb. 2005, Peer-reviwed, We report a high-energy femtosecond fiber amplifier based on an air-cladded single-transverse-mode erbium-ytterbium-codoped photonic-crystal fiber with a 26-mum mode-field-diameter. 700- fs, 47-MHz pulses at 1557 nm were amplified and compressed to near-transform-limited 100-fs, 7.4-nJ pulses with 54-kW peak powers without chirped-pulse amplification. A linearly polarized output with an extinction ratio exceeding 42 dB was obtained by double-pass configuration. As an application, supercontinuum spanning from 1000 to 2500 nm was generated by a successive 2-m high-nonlinear fiber with a 140-mW average power. (C) 2005 Optical Society of America.
Scientific journal, English

15aSF-7 干渉計型重力波検出器TAMA300開発の現状III : 変調系雑音(15aSF 重力波,宇宙線・宇宙物理領域)
佐藤 修一; 高森 昭光; 飯田 幸美; Bertolini A; DeSalvo R; 三代木 伸二; 長野 重夫; 安東 正樹; 森脇 成典; 神田 展行; 武者 満; 新井 宏二; 三尾 典克; 川村 静児; 藤本 眞克; 坪野 公夫; 大橋 正雄; 黒田 和明; TAMA Collaboration; 高橋 竜太郎; 阿久津 智忠; 中川 憲保; 辰巳 大輔; 常定 芳基; 福嶋 美津広; 山崎 利孝
一般社団法人 日本物理学会 日本物理学会講演概要集, The Physical Society of Japan (JPS), 60, 0, 38-38, 2005, Peer-reviwed
Scientific journal, English

Observation results by the TAMA300 detector on gravitational wave burst from stellar-core collapses
M.Ando; K.Arai; Y.Aso; P.Beyersdorf; K.Hayama; M.Musha et
Physical Review D, The American Physical Society, 71, 8, 082002, 2005, Peer-reviwed
Scientific journal, English

50-kW, 100-fs pulse generation by large-mode-area erbium-ytterbium-doped photonic-crystal fiber amplifier
A Shirakawa; J Ota; M Musha; K Ueda; Folkenberg, JR; J Broeng
2005 Conference on Lasers & Electro-Optics (CLEO), Vols 1-3, OPTICAL SOC AMERICA, 822-824, 2005, Peer-reviwed, A high-energy femtosecond fiber amplifier using a large-mode-area single-mode erbium-ytterbium-codoped photonic-crystal fiber is presented. 700-fs pulses at 1557nm were amplified and compressed to near-transform-limited 100-fs, 7.4-nJ pulses with > 50-kW peak powers without chirped-pulse amplification. (c) 2005 Optical Society of America
International conference proceedings, English

Blue up-conversion laser in Tm3+ doped ZBLAN glass fiber
GS Qin; S Huang; Y Feng; A Shirakawa; M Musha; K Ueda
2005 PACIFIC RIM CONFERENCE ON LASERS AND ELECTRO-OPTICS, IEEE, 428-429, 2005, Peer-reviwed, An 1120nm Raman fiber laser pumped Tm3+-doped ZBLAN fiber up-conversion laser was demonstrated with blue output power levels up to 116mW The effects of the reflectivity of the output coupler mirrors on blue laser were investigated. Based on our experimental results, we also found that there exists a competition between photodegradation and photocuring in the operation of blue fiber laser, which can affect the maximum output power of blue fiber laser greatly.
International conference proceedings, English

Large-mode-area erbium-ytterbium-doped photonic-crystal fiber amplifier yielding 54-kW femtosecond pulses without chirped-pulse amplification
A Shirakawa; M Musha; KI Ueda; Folkenberg, JR; J Broeng
2005 PACIFIC RIM CONFERENCE ON LASERS AND ELECTRO-OPTICS, IEEE, 228-229, 2005, Peer-reviwed, A high-energy femtosecond fiber amplifier using a large-mode-area single-mode erbium-ytterbium-codoped photonic-crystal fiber is presented. 700-fs pulses at 1557nm were amplified and compressed to near-transform-limited 100-fs, 7.4-nJ pulses with > 50-kW peak powers without chirped-pulse amplification.
International conference proceedings, English

Random laser study with nano-crystalline Nd3+: YAG powder
Y Feng; J Lu; S Huang; M Musha; K Ueda
2005 PACIFIC RIM CONFERENCE ON LASERS AND ELECTRO-OPTICS, IEEE, 214-215, 2005, Peer-reviwed, We have demonstrated lasing in Nd3+:YAG nano-crystalline powder with the help of one reflective mirrors by quasi-continuous-wave laser diode pumping. Microchip type random laser and random laser master oscillator ceramic power amplifier were also investigated.
International conference proceedings, English

1083nm single frequency ytterbium fiber laser
S Huang; Y Feng; G Qin; A Shirakawa; M Musha; K Ueda
2005 PACIFIC RIM CONFERENCE ON LASERS AND ELECTRO-OPTICS, IEEE, 636-637, 2005, Peer-reviwed, 1083nm single frequency ytterbium fiber laser was demonstrated by introducing loop mirror filter and fiber polarization controller in linear cavity. The loop mirror with unpumped ytterbium fiber discriminated and selected laser longitudinal modes efficiently.
International conference proceedings, English

Large-mode-area Erbium-Ytterbium-doped photonic-crystal fiber amplifier yielding 54-kW femtosecond pulses without chirped-pulse amplification
A. Shirakwa; J. Ota; M. Musha; K. Ueda
TOPS Advanced Solid-State Photonics, 98, 553-558, 2005, Peer-reviwed
Scientific journal, English

784-nm amplifier spontaneous emission from Tm3+-doped fluoride glass fiber pumped by an 1120-nm fiber lase
G. Qin; Sh. Huang; H. Feng; A. Shirakawa; M. Musha; K. Ueda
Optics Letters, 30, 269-271, 2005, Peer-reviwed
Scientific journal, English

116mW blue up-conversion fiber laser pumped by an 1120 Raman fiber laser
G. Qin; Sh. Huang; H. Fang; A. Shirakawa; M. Musha; K. Ueda
Optics Letters, 30, 269-271, 2005, Peer-reviwed
Scientific journal, English

Random microchip laser
Y Feng; SH Huang; GS Qin; M Musha; K Ueda
OPTICS EXPRESS, OPTICAL SOC AMER, 13, 1, 121-126, Jan. 2005, Peer-reviwed, A microchip-type laser with multiple scattering from powder as necessary feedback is demonstrated. The laser consists of a transparent ceramic Nd:YAG microchip and a Nd:YAG powder tablet, operates at quasi-continuous-wave regime pumped by a laser diode array. (C) 2005 Optical Society of America.
Scientific journal, English

Generation and Distribustion of the Stable mm-wave reference signal for ALMA
MitsuruMusha,YoheiSato; Ken'ichi Nakagawa; Ken-ichi Ueda. AkitoshiUeda; MasatoIshiguro
Proc. of NMIJ-BIPM Workshop, WS-11, 2005, Peer-reviwed
International conference proceedings, English

Robust and precise length correction of 25-km fiber for distribution of local oscillator
M Musha; Y Sato; K Nakagawa; K Ueda; A Ueda; M Ishiguro
2005 Digest of the LEOS Summer Topical Meetings, IEEE, 123-124, 2005, Peer-reviwed, In order to distribute local oscillators for the phased-array radio telescopes, the cycle-slip free fiber length stabilization system has been developed. The length of the 25km fiber was precisely measured by the Michelson interferometer with a digital phase frequency discriminator, and the length fluctuation of which was suppressed down to 2.5 mu m.
International conference proceedings, English

A highly stable mm-wave synthesizer realized by mixing two lasers locked to an optical frequency comb generator
M Musha; A Ueda; M Horikoshi; K Nakagawa; M Ishiguro; K Ueda; H Ito
OPTICS COMMUNICATIONS, ELSEVIER SCIENCE BV, 240, 1-3, 201-208, Oct. 2004, Peer-reviwed, Millimeter signal generation with high spectral purity and low phase fluctuations up to 100 GHz were demonstrated with an optical method in which two external-cavity laser diodes were phase-locked to an electro-optic modulator (EOM)-based optical frequency comb generator (OFCG). The additional phase noise caused from the cavity fluctuation in OFCG was completely canceled, and the phase noise of the heterodyne beat note of two LDs was determined only by that of the signal generator below offset frequency of 10 kHz. The detailed investigation of such a high frequency signal had never been done before, and the measured frequency of 100 GHz was limited only by the bandwidth of the phase noise detection system, and can be expanded up to more than 1 THz. (C) 2004 Elsevier B.V. All rights reserved.
Scientific journal, English

Single frequency ytterbium fiber laser from linear cavity with loop mirror filter
SH Huang; Y Feng; G Qin; A Shirakawa; M Musha; K Ueda
JAPANESE JOURNAL OF APPLIED PHYSICS PART 2-LETTERS & EXPRESS LETTERS, INST PURE APPLIED PHYSICS, 43, 10B, L1379-L1381, Oct. 2004, Peer-reviwed, Single frequency ytterbium fiber laser was demonstrated by combining polariztion controller and loop mirror filter in linear laser cavity. Spatial hole burning effect was eliminated by adjusting polarization controller appropriately. The loop mirror with unpumped ytterbium fiber as a narrow bandpass filter can discriminate laser longitudinal modes efficiently. Output power up to 11.7mW at 1064nm were obtained for lauched pump power of 68mW at 976nm, the slope efficiency is about 22%.
Scientific journal, English

Wavefront curvature sensing based on diffraction grating and fractional Fourier transforms
BH Zhu; A Shirakawa; M Musha; K Ueda; KD Cole
OPTICAL REVIEW, OPTICAL SOC JAPAN, 11, 5, 344-347, Sep. 2004, Peer-reviwed, We propose a new concept for wavefront curvature sensing, which is based on diffraction grating and fractional Fourier transforms systems. An explicit formula is derived expressing the wavefront curvature, and the wavefront shape can also be retrieved rapidly. The experimental setup is presented and numerical simulations show the validity of the proposed method. (C) 2004 The Optical Society of Japan.
Scientific journal, English

Present status of large-scale cryogenic gravitational wave telescope
T Uchiyama; K Kuroda; M Ohashi; S Miyoki; H Ishitsuka; K Yamamoto; H Hayakawa; K Kasahara; MK Fujimoto; S Kawamura; R Takahashi; T Yamazaki; K Arai; D Tatsumi; A Ueda; M Fukushima; S Sato; Y Tsunesada; ZH Zhu; T Shintomi; A Yamamoto; T Suzuki; Y Saito; T Haruyama; N Sato; Y Higashi; T Tomaru; K Tsubono; M Ando; K Numata; Y Aso; KI Ueda; H Yoneda; K Nakagawa; M Musha; N Mio; S Moriwaki; K Somiya; A Araya; A Takamori; N Kanda; S Telada; H Tagoshi; T Nakamura; M Sasaki; T Tanaka; KI Ohara; H Takahashi; S Nagano; O Miyakawa; ME Tobar
CLASSICAL AND QUANTUM GRAVITY, IOP PUBLISHING LTD, 21, 5, S1161-S1172, Mar. 2004, Peer-reviwed, The large-scale cryogenic gravitational wave telescope (LCGT) is the future project of the Japanese gravitational wave group. Two sets of 3 km arm length laser interferometric gravitational wave detectors will be built in a tunnel of Kamioka mine in Japan. LCGT will detect chirp waves from binary neutron star coalescence at 240 Mpc away with a S/N of 10. The expected number of detectable events in a year is two or three. To achieve the required sensitivity, several advanced techniques will be employed such as a low-frequency vibration-isolation system, a suspension point interferometer, cryogenic mirrors, a resonant side band extraction method, a high-power laser system and so on. We hope that the beginning of the project will be in 2005 and the observations will start in 2009.
Scientific journal, English

Thermal effects in quasi-continuous-wave Nd3+: Y3Al5O12 nanocrystalline-powder random laser
Y Feng; JF Bisson; Lu, JR; SH Huang; K Takaichi; A Shirakawa; M Musha; K Ueda
APPLIED PHYSICS LETTERS, AMER INST PHYSICS, 84, 7, 1040-1042, Feb. 2004, Peer-reviwed, We report an experimental investigation on the thermal effects in a Nd3+:Y3Al5O12 nanocrystalline-powder random laser with a one-mirror structure by quasi-continuous-wave laser diode pumping. Extremely low thermal conductivity in powder and significant temperature dependence of the narrow emission spectrum of Nd3+:Y3Al5O12 leads to a laser line redshift and gain reduction with a higher heat deposit. Mode drifting induced by the temperature dependence of the refractive index is also discussed. (C) 2004 American Institute of Physics.
Scientific journal, English

Optical generation of a highly stable mm-wave by heterodyning of two phase-locked LDs with an optical comb generator
Mitsuru Musha; Ken'ichi Nakagawa; Ken-ichi Ueda; Akitoshi Ueda; Masato Ishiguro
Proc. of CLEO2004, CTuH5, 79, 2004, Peer-reviwed
International conference proceedings, English

Lasing and refractive indices of nanocrystalline ceramics of cubic yttrium oxide Y2O3 doped with Nd3+ and Yb3+ ions
AA Kaminskii; K Ueda; AF Konstantinova; H Yagi; T Yanagitani; AV Butashin; VP Orekhova; J Lu; K Takaichi; T Uematsu; N Musha; A Shirokava
CRYSTALLOGRAPHY REPORTS, MAIK NAUKA/INTERPERIODICA/SPRINGER, 48, 6, 1041-1043, Nov. 2003, Peer-reviwed, A continuous-wave lasing at 1 mum was excited by the radiation of semiconductor laser diodes at room temperature in nanocrystalline ceramics Y2O3 doped with Nd3+ and Yb3+ ions. The refractive indices of the undoped nanocrystalline Y2O3 ceramics were measured in the wavelength range 0.4-9 mum. (C) 2003 MAIK "Nauka/Interperiodica".
Scientific journal, English

Diode-pumped mode-locked Yb3+: Y2O3 ceramic laser
A Shirakawa; K Takaichi; H Yagi; JF Bisson; J Lu; M Musha; K Ueda
OPTICS EXPRESS, OPTICAL SOC AMER, 11, 22, 2911-2916, Nov. 2003, Peer-reviwed, A diode-pumped femtosecond ytterbium laser with a host material of Y2O3 ceramics is reported. Passive mode locking by a semiconductor saturable-absorber mirror generates 98-MHz, 615-fs pulses at a center wavelength of 1076.5 nm. The average power is 420 mW and the pulse energy is 4.3 nJ with a 2.6-W absorbed pump power. To our knowledge, this is the first continuous-wave mode-locked ceramic laser. (C) 2003 Optical Society of America.
Scientific journal, English

Refractive indices of laser nanocrystalline ceramics based on Y3Al5O12
AA Kaminskii; K Ueda; AF Konstantinova; H Yagi; T Yanagitani; AV Butashin; VP Orekhova; J Lu; K Takaichi; T Uematsu; M Musha; A Shirokava
CRYSTALLOGRAPHY REPORTS, MAIK NAUKA/INTERPERIODICA PUBL, 48, 5, 868-871, Sep. 2003, Peer-reviwed, Refractive indices of the nanocrystalline Y3Al5O12 ceramic and a garnet single crystal of the same composition have been measured. In the visible and near IR range (0.4-1.064 mum), the prism method was used; in the medium IR range (2-6.2 mum), the interference method with the use of thin plates was applied. The refractive indices of these crystalline materials are practically the same over the entire spectral range studied and are described by the approximate formula proposed earlier for a single crystal. The parameters of the continuos-wave lasing in the nanocrystalline Y3Al5O12 ceramic doped with Nd3+ and Yb3+ ions measured recently are presented. (C) 2003 MAN "Nauka/Interperiodica".
Scientific journal, English

Supercontinuum generation using Raman fiber laser
M Prabhu; A Taniguchi; S Hirose; J Lu; M Musha; A Shirakawa; K Ueda
APPLIED PHYSICS B-LASERS AND OPTICS, SPRINGER-VERLAG, 77, 2-3, 205-210, Sep. 2003, Peer-reviwed, Using a phosphosilicate-doped continuous-wave Raman fiber laser, a 350-m single-mode fiber, and a 50% feedback fiber Bragg grating at 1483.4 nm, we obtained a high-efficiency ultra-broadband (1434 - 1527 nm) supercontinuum (SC) centered at 1483.4 nm with an average Output power of 2.1 W, a spectral intensity of 22.3 mW nm(-1), and a nonlinear conversion efficiency of 94%. Increasing the fiber length in the Raman cavity to 1840 in gave simultaneous SC centered at 1483.4 nm and 1239 nm. An average power of 2.3 W in the bandwidth of 1434-1544 nm and 0.2 W in the bandwidth of 1224-1257 nm is obtained. The temperature dependence of the SC was also investigated.
Scientific journal, English

Development of a multistage laser frequency stabilization for an interferometric gravitational-wave detector
S Nagano; S Kawamura; M Ando; R Takahashi; K Arai; M Musha; S Telada; MK Fujimoto; M Fukushima; Y Kozai; S Miyama; A Ueda; K Waseda; T Yamazaki; H Ishizuka; K Kuroda; S Matsumura; O Miyakawa; S Miyoki; M Ohashi; S Sato; D Tatsumi; T Tomaru; T Uchiyama; K Kawabe; N Ohishi; S Otsuka; A Sekiya; A Takamori; S Taniguchi; K Tochikubo; K Tsubono; K Ueda; K Yamamoto; N Mio; S Moriwaki; G Horikoshi; N Kamikubota; Y Ogawa; Y Saito; T Suzuki; K Nakagawa; K Ueda; A Araya; N Kanda; N Kawashima; E Mizuno; MA Barton; N Tsuda; N Matsuda; T Nakamura; M Sasaki; M Shibata; H Tagoshi; T Tanaka; K Nakao; K Oohara; Y Kojima; T Futamase; H Asada
REVIEW OF SCIENTIFIC INSTRUMENTS, AMER INST PHYSICS, 74, 9, 4176-4183, Sep. 2003, Peer-reviwed, Laser frequency stabilization is essential for interferometric gravitational-wave detectors to attain their target sensitivity. We have designed a multistage laser frequency stabilization system which has been applied in the development of the TAMA 300 gravitational-wave detector in Japan. The control topology consisting of two cascaded loops were employed to secure high feedback gain and reliable detector operation and thus allow the best frequency stability and uninterrupted long-term observation. We achieved simultaneously a frequency stability of 5x10(-5) Hz/rootHz, and a common-mode rejection ratio (which reduces the coupling of frequency noise to spurious signals in the detector) of 37 dB. The developed system enabled us to operate TAMA 300 with sufficient sensitivity and stability that it had the potential to register gravitational-wave events. The system was confirmed to be suitable for a gravitational-wave detector from the observation run of TAMA 300. (C) 2003 American Institute of Physics.
Scientific journal, English

Yb3+: Sc2O3 ceramic laser
J Lu; JF Bisson; K Takaichi; T Uematsu; A Shirakawa; M Musha; K Ueda; H Yagi; T Yanagitani; AA Kaminskii
APPLIED PHYSICS LETTERS, AMER INST PHYSICS, 83, 6, 1101-1103, Aug. 2003, Peer-reviwed, A solid-state laser material based on highly transparent Yb3+-doped scandia (Sc2O3) ceramic was developed using nanocrystalline technology and the nonpress vacuum sintering method. Continuous wave laser oscillations were obtained at around 1041 and 1094 nm using a 2.5 at. % Yb3+:Sc2O3 ceramic plate. Broadband lasing spectra were observed. (C) 2003 American Institute of Physics.
Scientific journal, English

Nd3+: YGdO3 ceramic laser
J Lu; K Takaichi; T Uematsu; A Shirakawa; M Musha; JF Bisson; K Ueda; H Yagi; T Yanagitani; AA Kaminskii
LASER PHYSICS, INTERPERIODICA, 13, 7, 940-942, Jul. 2003, Peer-reviwed, A highly transparent Nd3+:YGdO3 ceramic solid-state laser material was developed using nanocrystalline technology and a nonpress vacuum sintering method. Spectroscopic properties of this ceramic laser material were investigated. Laser diode end-pumped continuous wave laser oscillation was demonstrated at 1078.1 nm in the F-4(3/2) --> I-4(11/2) transition channel.
Scientific journal, English

New data on the physical properties of Y3Al5O12-based nanocrystalline laser ceramics
AA Kaminskii; MS Akchurin; Alshits, VI; K Ueda; K Takaichi; J Lu; T Uematsu; M Musha; A Shirikawa; Gabler, V; HJ Eichler; H Yagi; T Yanagitani; SN Bagayev; J Fernandez; R Balda
CRYSTALLOGRAPHY REPORTS, MAIK NAUKA/INTERPERIODICA PUBL, 48, 3, 515-519, May 2003, Peer-reviwed, Microhardness and fracture toughness of highly transparent Y3Al5O12- and Y3Al5O12 : Nd3+-based nanocrystalline ceramics are measured for the first time. For the Y3A'5012 : Nd 3, laser ceramics, the use ofa longitudinal scheme with a diode-laser pumping at a wavelength of 1.3186 mum (F-4(3/2) --> I-4(13/2) channel) enabled one to attain an output power of continuous-wave lasing of similar to3.7 W with 35% efficiency. (C) 2003 MAIK "Nauka/Interperiodica".
Scientific journal, English

Refractive indices of nanocrystalline ceramics of cubic yttrium oxide Y3OAl5O12
A. Kaminskii; K. Ueda; A. Konstantinova; H. Yagi; T. Yanagitani; A. Butashin; V. Orekhova; J. Lu; K. Takaichi; H. Yoneda; M. Musha; A. Shirakawa
Cryastallography Report, 48, 930-933, 2003, Peer-reviwed
Scientific journal, English

New results on investigation of physical properties of monocrystalline laser ceramic on the base of Y3Al5O12
A. Kaminskii; M. Akchurin; V. Alshits; K. Ueda; K. Takaichi; J. Lu; T. Uematsu; M. Musha; A. SHirakawa; V. Gabler; H. Eichiler; H. Yagi; T. Yanagitani; S. Baga
Crystallography Reports, 48, 515-519, 2003, Peer-reviwed
Scientific journal, English

Promising ceramic laser material: Highly transparent Nd3+: Lu2O3 ceramic
J Lu; K Takaichi; T Uematsu; A Shirakawa; M Musha; K Ueda; H Yagi; T Yanagitani; AA Kaminskii
APPLIED PHYSICS LETTERS, AMER INST PHYSICS, 81, 23, 4324-4326, Dec. 2002, Peer-reviwed, A solid-state laser material based on highly transparent cubic Nd3+:Lu2O3 ceramic was developed using nanocrystalline technology and a nonpress vacuum sintering method. Spectroscopic properties of this ceramic laser material were investigated. At room temperature under single-laser diode pumping, efficient continuous wave laser oscillation was demonstrated at two wavelengths of the F-4(3/2)-->I-4(11/2) channel. The potential application of such a laser material was also discussed. (C) 2002 American Institute of Physics.
Scientific journal, English

Yb3+: Y2O3 ceramics - a novel solid-state laser material
Lu, JR; K Takaichi; T Uematsu; A Shirakawa; M Musha; K Ueda; H Yagi; T Yanagitani; AA Kaminskii
JAPANESE JOURNAL OF APPLIED PHYSICS PART 2-LETTERS, INST PURE APPLIED PHYSICS, 41, 12A, L1373-L1375, Dec. 2002, Peer-reviwed, A new solid-state laser based on Yb3+-doped highly transparent nanocrystalline yttria (Y2O3) ceramics was developed. At room temperature and under a pump power of 2.63 W from a single InGaAs laser diode at approximate to 0.94 mum, a continuous-wave laser output of 0.47 W at 1.077 mum wavelength was obtained corresponding to a slope efficiency of about 32%. Some main spectroscopic properties of Yb3+:Y2O3 ceramics were also investigated.
Scientific journal, English

1212 nm pumping of 2 mu m Tm-Ho-codoped silica fiber laser
A Taniguchi; T Kuwayama; A Shirakawa; M Musha; K Ueda; M Prabhu
APPLIED PHYSICS LETTERS, AMER INST PHYSICS, 81, 20, 3723-3725, Nov. 2002, Peer-reviwed, A Tm-Ho-codoped silica fiber laser pumped by a third-stokes Raman Fiber Laser at 1212 nm is demonstrated. For the 30-cm-long Tm-Ho-codoped fiber, a 400 mW output power is obtained at a wavelength of 1790 nm due to the laser emission from the Tm3+ ions. For the 270-cm-long Tm-Ho-codoped fiber, a 450 mW output power is obtained at 1970 nm due to the laser emission from Ho3+ ions. (C) 2002 American Institute of Physics.
Scientific journal, English

Development of High Power and Highly-stabilized Light Source for Gravitational Wave Detector
Mitsuru Musha; Ken'ichi Nakagawa; Ken-ichi Ueda
Proc. of URSI General Assembly, 0776, 2002, Peer-reviwed
International conference proceedings, English

Intensity and frequency noise characteristics of two coherently-added injection-locked Nd : YAG lasers
M Musha; T Kanaya; K Nakagawa; KI Ueda
APPLIED PHYSICS B-LASERS AND OPTICS, SPRINGER-VERLAG, 73, 3, 209-214, Sep. 2001, Peer-reviwed, Coherent addition of two injection-locked Nd:YAG lasers has been performed. A maximum output power of 4.4 W and addition efficiency of 0.94 was achieved, which is die highest power-coupling efficiency ever reported. It was shown experimentally that the frequency and intensity noise level of the coherently-added laser are the same as those of a single injection-locked laser. In particular, no additional intensity noise was observed above the relaxation oscillation frequency of the slave laser, which is suitable for use as the light source for a future gravitational wave detector. The frequency noise of the coherently-added laser was suppressed to 1 x 10(-4) Hz/root Hz by controlling that of the master laser, and the intensity noise was also suppressed to 1 x 10(-8) /root Hz by controlling the intensity of pump lasers used for the slave lasers.
Scientific journal, English

Stable operation of a 300-m laser interferometer with sufficient sensitivity to detect gravitational-wave events within our galaxy
M.Ando; K.Arai; R.Takahashi; G.Heinzel; S.Kawamura; M.Musha et
Physical Review Letters, The American Physical Society, 86, 18, 3950-3954, 2001, Peer-reviwed, The TAMA300 interferometer was operated stably for over 10 h without loss of lock. The observed sensitivity and stability indicate that TAMA has the ability to detect GW events within the galaxy.
Scientific journal, English

Supercontinuum generation centered at 1483.4nm and 1239nm using Raman fiber laser
M Prabhu; T Saitou; A Taniguchi; L Jianren; JQ Xu; NS Kim; M Musha; A Shirakawa; K Ueda
CLEO(R)/PACIFIC RIM 2001, VOL II, TECHNICAL DIGEST, IEEE, 156-157, 2001, Peer-reviwed, Simultaneous CW supercontinuum (SC) centered at 1239nm (1218-1260nm) and 1483.4mn (1434-1544nm) is obtained when 350m singlemode fiber is spliced to P-doped cascaded Raman fiber laser. The SC output is investigated for different P-doped fiber lengths.
International conference proceedings, English

Coherent addition of two injection-locked Nd : YAG lasers
M Musha; T Kanaya; K Nakagawa; K Ueda
CLEO(R)/PACIFIC RIM 2001, VOL I, TECHNICAL DIGEST, IEEE, 1, 552-553, 2001, Peer-reviwed, Two Nd:YAG lasers injected by the same master laser were coherently added, whose maximum output power and the coupling efficiency was 4.5W and 0.95, respectively. The intensity and frequency noise stabilization has been done.
International conference proceedings, English

The short- and long-term frequency stabilization of an injection-locked Nd : YAG laser in reference to a Fabry-Perot cavity and an iodine saturated absorption line
M Musha; T Kanaya; K Nakagawa; K Ueda
OPTICS COMMUNICATIONS, ELSEVIER SCIENCE BV, 183, 1-4, 165-173, Sep. 2000, Peer-reviwed, We have developed a wideband frequency-stabilized injection-locked Nd:YAG laser as a light source for the laser interferometric gravitational wave detector, in which short-term frequency stability of the laser improves the sensitivity of the interferometer and the long-term frequency stability aims for the stable long-time operation of the interferometer. The frequency of a 2-W injection-locked laser is locked to both a rigid Fabry-Perot cavity with ULE spacer and saturated I-127(2) simultaneously with two nested servo loops, and the long-term as well as short-term frequency absorption line of stability are obtained. The drift of the resonant frequency of the rigid Fabry-Perot cavity is measured and the stability of the Fabry-Perot cavity is estimated to be 20 X f(-1) [Hz/root Hz]. The predicted frequency stabilities of the present dual-reference-locked laser are numerically simulated. Our wideband frequency-stabilized laser is also available for the high-resolution spectroscopy. (C) 2000 Elsevier Science B.V. All rights reserved.
Scientific journal, English

Large-scale cryogenic gravitational wave telescope
K Kuroda; M Ohashi; S Miyoki; D Tatsumi; S Sato; H Ishizuka; MK Fujimoto; S Kawamura; R Takahashi; T Yamazaki; K Arai; M Fukushima; K Waseda; S Telada; A Ueda; T Shintomi; A Yamamoto; T Suzuki; Y Saito; T Haruyama; N Sato; K Tsubono; K Kawabe; M Ando; KI Ueda; H Yoneda; M Musha; N Mio; S Moriwaki; A Araya; N Kanda; ME Tobar
INTERNATIONAL JOURNAL OF MODERN PHYSICS D, WORLD SCIENTIFIC PUBL CO PTE LTD, 8, 5, 557-579, Oct. 1999, Peer-reviwed, We present here the Large-scale Cryogenic Gravitational wave Telescope (LCGT) project which is aimed to improve the sensitivity of the existing gravitational wave projects by ten times. LCGT is the project constructing the km-scale gravitational wave detector in Japan succeeding the TAMA project, which adopts cryogenic mirrors with a higher power laser. We are planing to build it in an underground site in Kamioka mine. If its target sensitivity is attained, we will be able to catch a few events per month.
Scientific journal, English

Absolute-length determination of a long-baseline Fabry-Perot cavity by means of resonating modulation sidebands
A Araya; S Telada; K Tochikubo; S Taniguchi; R Takahashi; K Kawabe; D Tatsumi; T Yamazaki; S Kawamura; S Miyoki; S Moriwaki; M Musha; S Nagano; MK Fujimoto; K Horikoshi; N Mio; Y Naito; A Takamori; K Yamamoto
APPLIED OPTICS, OPTICAL SOC AMER, 38, 13, 2848-2856, May 1999, Peer-reviwed, A new method has been demonstrated for absolute-length measurements of a long-baseline Fabry-Perot cavity by use of phase-modulated light. This method is based on determination of a free spectral range (FSR) of the cavity from the frequency difference between a carrier and phase-modulation sidebands, both of which resonate in the cavity. Sensitive response of the Fabry-Perot cavity near resonant frequencies ensures accurate determination of the FSR and thus of the absolute length of the cavity. This method was applied to a 300-m Fabry-Perot cavity of the TAMA gravitational wave detector that is being developed at the National Astronomical Observatory, Tokyo. With a modulation frequency of similar to 12 MHz, we successfully determined the absolute cavity length with resolution of 1 mu m (3 X 10(-9) in strain) and observed local ground strain variations of 6 x 10(-8). (C) 1999 Optical Society of America OCIS codes: 120.2230, 120.3180, 120.3940, 120.5060.
Scientific journal, English

Frequency stabilized solid state laser
Mitsuru Musha; Ken-ichi Ueda
CRL International Symposium, Tokyo, 1, Mar. 1999
International conference proceedings, Japanese

Lasers Application to the Studies of Gravitation Waves
K. Ueda; M. Musha
LASER OPTICS '98, St. Petersburg, Russia, 22-26, Jan. 1999
Japanese

The interferometric gravitational wave detector TAMA-300 and the frequency-stabilized laser with high-finesse optical resonator
M Musha; A Ueda; M Ohashi; K Ueda
LASER RESONATORS II, SPIE-INT SOC OPTICAL ENGINEERING, 3611, 65-72, 1999, Peer-reviwed, The laser interferometric gravitational wave detection by means of a long-baseline laser interferometer has been promoted in Japan. To obtain higher sensitivity for detect gravitational wave, high-quality mirrors and the high-power laser with high frequency-stability are important. In this paper our improvement of high-quality mirrors through development of high-precision measurement and the frequency stabilization of the injection-locked laser was reported.
International conference proceedings, English

The Interferometric Gravitational wave detector TAMA300 and the frequency-stabilized laser with high-finesse optical resonator(invited)
Mitsuru Musha; Akitoshi Ueda; Ken-ichi Ueda; Masatake Ohashi
Proc. of SPIE, 3611, 35-72, Jan. 1999, Peer-reviwed
International conference proceedings, English

重力波検出用の超高安定化高出力固体レーザーシステム
武者満; 中川賢一; 植田憲一
レーザー研究, レ-ザ-学会, 27, 7, 84-88, 1999
Research society, Japanese

Frequency stabilized injection-locked laser
Mitsuru Musha; Takeshi Kanaya; Ken-ichi Ueda
Proc. of SPIE, 3889, 398-404, 1999, Peer-reviwed
International conference proceedings, English

注入同期Nd:YAGレーザーの広帯域周波数安定化
武者満; 金谷剛; 中川賢一; 植田憲一
Microoptics News, 17, 4, 7, 1999, Peer-reviwed
Scientific journal, Japanese

Investigation of an injection-locked Nd : YAG laser for the gravitational wave detection
S Nagano; M Musha; L Ying; N Mio; K Ueda
LASER PHYSICS, INTERPERIODICA, 8, 3, 686-691, May 1998, Peer-reviwed, We have investigated the injection-locked Nd :YAG laser for laser interferometric gravitational wave detectors; their light sources must have high power output, high frequency, and intensity stability. In this paper, we report the frequency stabilization of a prototype 2-W injection-locked laser and intensity noise stabilization of the 10-W injection-locked laser which will be installed in our 300-m laser interferometer.
Scientific journal, English

Wideband and high frequency stabilization of an injection-locked Nd:YAG laser to a high-finesse Fabry-Perot cavity
M Musha; K Nakagawa; K Ueda
OPTICS LETTERS, OPTICAL SOC AMER, 22, 15, 1177-1179, Aug. 1997, Peer-reviwed, High frequency stabilization of a 2.2-W injection-locked laser-diode-pumped Nd:YAG laser to a high-finesse optical cavity has been realized by frequency control of the master laser. With the help of an external electro-optical modulator, the feedback bandwidth was extended to 1 MHz and the frequency noise relative to the reference cavity was suppressed to 3 x 10(-4) Hz/Hz(1/2) below 1 kHz. This feedback laser system is an ideal laser source for gravitational wave detectors, which require both ultralow frequency noise and high output power. (C) 1997 Optical Society of America.
Scientific journal, English

Orthorhombic ferroelectric and ferroelastic Gd-2(MoO4)(3) crystal - A new many-purposed nonlinear and optical material: Efficient multiple stimulated Raman scattering and CW and tunable second harmonic generation
AA Kaminskii; AV Butashin; HJ Eichler; D Grebe; R Macdonald; K Ueda; H Nishioka; W Odajima; M Tateno; J Song; M Musha; SN Bagaev; AA Pavlyuk
OPTICAL MATERIALS, ELSEVIER SCIENCE BV, 7, 3, 59-73, Mar. 1997, Peer-reviwed, The nonlinear optical properties of a ferroelectric and ferroelastic beta'-Gd-2(MoO4)(3) laser crystal-host were studied by second harmonic generation (SHG) and stimulated Raman scattering (SRS) experiments using different laser sources for excitation. It is shown that the investigated crystals are very attractive for SHG with IR CW lasers as well as for continuously tunable SHG under illumination with a femtosecond hyper-continuum light source. Furthermore, up to five Stokes and five anti-Stokes lines have been obtained in picosecond SRS experiments with a total conversion efficiency of about 70%. Interaction of SHG and SRS, as well as a new effect, which may be called quasi-hyper SRS, have been observed with insulating crystal for the first time. We classify the beta'-Gd-2(MoO4)(3):Nd as a promising laser medium for pulsed and CW self-frequency doubling lasers.
Scientific journal, English

A Highly Frequency -stabilized Injection-locked Nd:YAG Laser for the Light Source of a gravitaional Wave Antenna
Mitsuru Musha; Ken'ichi Nakagawa; Ken-ichi Ueda
Proc. of 13th International Conference on Laser Spectroscopy, **, 1997, Peer-reviwed
International conference proceedings, English

Coherent Addtion of injection-locked Nd:YAG lasers
M.Musha; T.Kanaya; K.Nakagawa; K.Ueda
Proc. of CLEO/Pacific Rim'97, **, 1997, Peer-reviwed
International conference proceedings, English

DEVELOPMENT OF ALL-SEMICONDUCTOR LASER SOURCES FOR STUDIES OF SR-88(+) IONS CONFINED IN RF TRAP
M MUSHA; A ZVYAGIN; K NAKAGAWA; M OHTSU
JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS SHORT NOTES & REVIEW PAPERS, JAPAN J APPLIED PHYSICS, 33, 3B, 1603-1607, Mar. 1994, Peer-reviwed, Semiconductor-laser-based light sources have been developed for cooling and depopulating Sr+ ions confined in an rf trap. Single-mode laser oscillation at 422 nm and 21 muW power was obtained, which corresponds to transition 5s S-2(1/2)5p P-2(1/2) of Sr+. An external-cavity-stabilized semiconductor laser with 1.8 mW power has been developed for pumping ions back from the 4d 2D3/2 metastable state to the cooling cycle. In this paper we present the reference spectrum for both lasers, which confirms the laser oscillation at appropriate transition of Sr+.
Scientific journal, English

ABSORPTION LINESHAPE OF A TRAPPED AND COOLED ION
VA ALEKSEEV; DD KRYLOVA; M MUSHA
OPTICS COMMUNICATIONS, ELSEVIER SCIENCE BV, 106, 1-3, 100-112, Mar. 1994, Peer-reviwed, The correlation function and the shape of the absorption spectrum of an ion in a trap cooled by a laser beam are calculated. The stochastic ion motion caused by the cooling process and by the collisions with the background gas particles is described by a Fokker-Planck equation. Two cases of continuous and interrupted cooling are investigated. In the first case the laser beam continuously cools the ion during the absorption investigation. In the second case the cooling laser beam is turned off before the beginning of the absorption investigation and the collisions with the particles of background ps heat up the cooled ion.
Scientific journal, English

Research on precise orbit determination equipment for future satellite navigation system-Development of high-precision accelerometer and optical frequency reference system-
瀧口博士; 松下紗也; 佐々木俊崇; 秋山恭平; 山田英輝; 末正有; 成田秀樹; 橋本洋輔; 河野功; 長野晃士; 和泉究; 竹内裕一; 武者満; 安東正樹; 佐藤修一
2022, 日本測地学会講演会要旨, 138th, 202302236850442392

10aAW-3 Highly sensitive molecular spectroscopy using dual-comb spectrometer
Watanabe Naoto; Musha Mitsuru; Nakagawa Ken'ichi
The Physical Society of Japan (JPS), 22 Aug. 2014, Meeting abstracts of the Physical Society of Japan, 69, 2, 101-101, Japanese, 1342-8349, 110009875536, AA11439205

21aSB-4 スペース重力波アンテナDECIGO計画(55) : DECIGO/DPFの概要(21aSB 重力波(KAGRA,DECIGO,TOBA,検出器),宇宙線・宇宙物理領域)
安東 正樹; 川村 静児; 瀬戸 直樹; 中村 卓史; 坪野 公夫; 佐藤 修一; 田中 貴浩; 船木 一幸; 沼田 健司; 神田 展行; 井岡 邦仁; 高島 健; 横山 順一; 阿久津 智忠; 武者 満; 上田 暁俊; 麻生 洋一; 新谷 昌人; 坂井 真一郎; 青柳 巧介; 我妻 一博; 浅田 秀樹; 新井 宏二; 池上 健; 石川 毅彦; 石崎 秀晴; 石原 秀樹; 和泉 究; 市來 淨與; 伊東 宏之; 伊藤 洋介; 井上 開輝; 植田 憲一; 牛場 崇文; 歌島 昌由; 江口 智士; 江尻 悠美子; 榎 基宏; 戎崎 俊一; 江里口 良治; 大石 奈緒子; 大河 正志; 大橋 正健; 大原 謙一; 大渕 喜之; 岡田 健志; 岡田 則夫; 奥富 弘基; 河島 信樹; 川添 史子; 河野 功; 木内 建太; 岸本 直子; 國中 均; 國森 裕生; 黒田 和明; 黒柳 幸子; 小泉 宏之; 洪 鋒雷; 郡 和範; 穀山 渉; 苔山 圭以子; 古在 由秀; 小嶌 康史; 固武 慶; 小林 史歩; 権藤 里奈; 西條 統之; 齊藤 遼; 阪上 雅昭; 阪田 紫帆里; 佐合 紀親; 佐々木 節; 佐藤 孝; 柴田 大; 柴田 和憲; 正田 亜八香; 真貝 寿明; 末正 有; 杉山 直; 鈴木 理恵子; 諏訪 雄大; 宗宮 健太郎; 祖谷 元; 高野 忠; 高橋 走; 高橋 慶太郎; 高橋 弘毅; 高橋 史宜; 高橋 龍一; 高橋 竜太郎; 高森 昭光; 田越 秀行; 田代 寛之; 田中 伸幸; 谷口 敬介; 樽家 篤史; 千葉 剛; 陳 たん; 辻川 信二; 常定 芳基; 豊嶋 守生; 鳥居 泰男; 中尾 憲一; 中澤 知洋; 中須賀 真一; 中野 寛之; 長野 重夫; 中村 康二; 中山 宜典; 西澤 篤志; 西田 恵里奈; 西山 和孝; 丹羽 佳人; 能見 大河; 橋本 樹明; 端山 和大; 原田 知広; 疋田 渉; 姫本 宣朗; 平林 久; 平松 尚志; 福嶋 美津広; 藤田 龍一; 藤本 眞克; 二間瀬 敏史; 細川 瑞彦; 堀澤 秀之; 前田 恵一; 松原 英雄; 松本 伸之; 道村 唯太; 宮川 治; 宮本 雲平; 三代木 伸二; 向山 信治; 森澤 理之; 森本 睦子; 森脇 成典; 八木 絢外; 山川 宏; 山崎 利孝; 山元 一広; 吉田 至順; 吉野 泰造; 柳 哲文; 若林 野花
一般社団法人 日本物理学会, 2014, 日本物理学会講演概要集, 69.2.1, 49, Japanese, 2189-0803, 110009873474

Development of a frequency-stabilized laser for DPF
武者 満; 末正 有; 中川 賢一
日本航空宇宙学会, 09 Oct. 2013, 宇宙科学技術連合講演会講演集, 57, 3p, Japanese, 1884-1945, 40020220589

Dual-comb spectroscopy using two electro-optic modulator based frequency combs II
Watanabe Naoto; Kitamura Toshiyuki; Terui Rika; Musha Mitsuru; Nakagawa Ken'ichi
The Physical Society of Japan (JPS), 26 Aug. 2013, Meeting abstracts of the Physical Society of Japan, 68, 2, 168-168, Japanese, 1342-8349, 110009754744, AA11439205

27pEE-9 Dual-comb spectroscopy using two electro-optic modulator based frequency combs
Watanabe Naoto; Kitamura Toshiyuki; Musha Mitsuru; Nakagawa Ken'ichi
The Physical Society of Japan (JPS), 26 Mar. 2013, Meeting abstracts of the Physical Society of Japan, 68, 1, 221-221, Japanese, 1342-8349, 110009643209, AA11439205

27aBE-12 Developments of the highly-stabilized light source for DPF
Suemasa Aru; kanoh Naoki; Musha Mitsuru; Nakagawa Ken'ichi; Ueda Ken-ichi
The Physical Society of Japan (JPS), 26 Mar. 2013, Meeting abstracts of the Physical Society of Japan, 68, 1, 131-131, Japanese, 1342-8349, 110009642903, AA11439205

11pSN-5 Developments of the highly-stabilized light souece for DPF
Musha Mitsuru; Nagaku Atsushi; Nakagawa Ken'ichi; Ueda Ken-ichi
The Physical Society of Japan (JPS), 24 Aug. 2012, Meeting abstracts of the Physical Society of Japan, 67, 2, 99-99, Japanese, 1342-8349, 110009599732, AA11439205

BI-1-7 Space gravitational wave detector : DECIGO & DPF
Sun Ke-Xun; Musha Mitsuru
本文データは学協会の許諾に基づきCiNiiから複製したものである, The Institute of Electronics, Information and Communication Engineers, Mar. 2010, Proceedings of the IEICE General Conference, 2010, 1, SS_85-SS-86, Japanese, 1349-1369, 110007883799

DECIGO: The Japanese space gravitational wave antenna
Shuichi Sato; Seiji Kawamura; Masaki Ando; Takashi Nakamura; Kimio Tsubono; Akito Araya; Ikkoh Funaki; Kunihito Ioka; Nobuyuki Kanda; Shigenori Moriwaki; Mitsuru Musha; Kazuhiro Nakazawa; Kenji Numata; Shin Ichiro Sakai; Naoki Seto; Takeshi Takashima; Takahiro Tanaka; Kazuhiro Agatsuma; Koh Suke Aoyanagi; Koji Arai; Hideki Asada; Yoichi Aso; Takeshi Chiba; Toshikazu Ebisuzaki; Yumiko Ejiri; Motohiro Enoki; Yoshiharu Eriguchi; Masa Katsu Fujimoto; Ryuichi Fujita; Mitsuhiro Fukushima; Toshifumi Futamase; Katsuhiko Ganzu; Tomohiro Harada; Tatsuaki Hashimoto; Kazuhiro Hayama; Wataru Hikida; Yoshiaki Himemoto; Hisashi Hirabayashi; Takashi Hiramatsu; Feng Lei Hong; Hideyuki Horisawa; Mizuhiko Hosokawa; Kiyotomo Ichiki; Takeshi Ikegami; Kaiki TInoue; Koji Ishidoshiro; Hideki Ishihara; Takehiko Ishikawa; Hideharu Ishizaki; Hiroyuki Ito; Yousuke Itoh; Nobuki Kawashima; Fumiko Kawazoe; Kishimoto Naoko; Kenta Kiuchi; Shiho Kobayashi; Kazunori Kohri; Hiroyuki Koizumi; Yasufumi Kojima; Keiko Kokeyama; Wataru Kokuyama; Kei Kotake; Yoshihide Kozai; Hideaki Kudoh; Hiroo Kunimori; Hitoshi Kuninaka; Kazuaki Kuroda; Kei Ichi Maeda; Hideo Matsuhara; Yasushi Mino; Osamu Miyakawa; Shinji Miyoki; Mutsuko YMorimoto; Tomoko Morioka; Toshiyuki Morisawa; Shinji Mukohyama; Shigeo Nagano; Isao Naito; Kouji Nakamura; Hiroyuki Nakano; Kenichi Nakao; Shinichi Nakasuka; Yoshinori Nakayama; Erina Nishida; Kazutaka Nishiyama; Atsushi Nishizawa; Yoshito Niwa; Taiga Noumi; Yoshiyuki Obuchi; Masatake Ohashi; Naoko Ohishi; Masashi Ohkawa; Norio Okada; Kouji Onozato; Kenichi Oohara; Norichika Sago; Motoyuki Saijo; Masaaki Sakagami; Shihori Sakata; Misao Sasaki
DECi-hertz Interferometer Gravitational wave Observatory (DECIGO) is the planned Japanese space gravitational wave antenna, aiming to detect gravitational waves from astrophysically and cosmologically significant sources mainly between 0.1 Hz and 10 Hz and thus to open a new window for gravitational wave astronomy and for the universe. DECIGO will consist of three drag-free spacecraft, 1000 km apart from each other, whose relative displacements are measured by a differential Fabry-Perot interferometer. We plan to launch DECIGO in middle of 2020s, after sequence of two precursor satellite missions, DECIGO pathfinder and Pre-DECIGO, for technology demonstration required to realize DECIGO and hopefully for detection of gravitational waves from our galaxy or nearby galaxies. © 2009 IOP Publishing Ltd., 03 Jun. 2009, Journal of Physics: Conference Series, 154, 1742-6588, 66149100099

DECIGO pathfinder
Masaki Ando; Seiji Kawamura; Shuichi Sato; Takashi Nakamura; Kimio Tsubono; Akito Araya; Ikkoh Funaki; Kunihito Ioka; Nobuyuki Kanda; Shigenori Moriwaki; Mitsuru Musha; Kazuhiro Nakazawa; Kenji Numata; Shin Ichiro Sakai; Naoki Seto; Takeshi Takashima; Takahiro Tanaka; Kazuhiro Agatsuma; Koh Suke Aoyanagi; Koji Arai; Hideki Asada; Yoichi Aso; Takeshi Chiba; Toshikazu Ebisuzaki; Yumiko Ejiri; Motohiro Enoki; Yoshiharu Eriguchi; Masa Katsu Fujimoto; Ryuichi Fujita; Mitsuhiro Fukushima; Toshifumi Futamase; Katsuhiko Ganzu; Tomohiro Harada; Tatsuaki Hashimoto; Kazuhiro Hayama; Wataru Hikida; Yoshiaki Himemoto; Hisashi Hirabayashi; Takashi Hiramatsu; Feng Lei Hong; Hideyuki Horisawa; Mizuhiko Hosokawa; Kiyotomo Ichiki; Takeshi Ikegami; Kaiki T. Inoue; Koji Ishidoshiro; Hideki Ishihara; Takehiko Ishikawa; Hideharu Ishizaki; Hiroyuki Ito; Yousuke Itoh; Nobuki Kawashima; Fumiko Kawazoe; Naoko Kishimoto; Kenta Kiuchi; Shiho Kobayashi; Kazunori Kohri; Hiroyuki Koizumi; Yasufumi Kojima; Keiko Kokeyama; Wataru Kokuyama; Kei Kotake; Yoshihide Kozai; Hideaki Kudoh; Hiroo Kunimori; Hitoshi Kuninaka; Kazuaki Kuroda; Kei Ichi Maeda; Hideo Matsuhara; Yasushi Mino; Osamu Miyakawa; Shinji Miyoki; Mutsuko Y. Morimoto; Tomoko Morioka; Toshiyuki Morisawa; Shinji Mukohyama; Shigeo Nagano; Isao Naito; Kouji Nakamura; Hiroyuki Nakano; Kenichi Nakao; Shinichi Nakasuka; Yoshinori Nakayama; Erina Nishida; Kazutaka Nishiyama; Atsushi Nishizawa; Yoshito Niwa; Taiga Noumi; Yoshiyuki Obuchi; Masatake Ohashi; Naoko Ohishi; Masashi Ohkawa; Norio Okada; Kouji Onozato; Kenichi Oohara; Norichika Sago; Motoyuki Saijo; Masaaki Sakagami; Shihori Sakata; Misao Sasaki
DECIGO pathfinder (DPF) is a milestone satellite mission for DECIGO (DECihertz Interferometer Gravitational wave Observatory), which is a future space gravitational wave antenna. DECIGO is expected to provide fruitful insights into the universe, particularly about dark energy, the formation mechanism of supermassive black holes and the inflation of the universe. Since DECIGO will be an extremely challenging mission, which will be formed by three drag-free spacecraft with 1000 km separation, it is important to increase the technical feasibility of DECIGO before its planned launch in 2024. Thus, we are planning to launch two milestone missions: DPF and pre-DECIGO. In this paper, we review the conceptual design and current status of the first milestone mission, DPF. © 2009 IOP Publishing Ltd., IOP PUBLISHING LTD, 07 May 2009, Classical and Quantum Gravity, 26, 9, English, 0264-9381, 1361-6382, 77955182093, WOS:000265349600020

30pSC-1 Space Gravitational Wave Antenna DECIGO (17) : Design, Project
Kawamura Seiji
The Physical Society of Japan, 2009, Meeting Abstracts of the Physical Society of Japan, 64.1.1, 100, Japanese, 2189-0803, 110007370099

20pZA-3 Absolute frequency measurement of a Sr optical lattice clock using coherent optical carrier transfer over a 120-km fiber
Hong F.-L; Musha M; Takamoto M; Inaba H; Yanagimachi S; Takamizawa A; Watabe K; Ikegami T; Imae M; Fujii Y; Amemiya M; Nakagawa K; Ueda K; Katori H
The Physical Society of Japan (JPS), 2008, Meeting Abstracts of the Physical Society of Japan, 63, 0, Japanese, 1342-8349, 110006982761

Developments and Applications of the Acetylene Stabilized Laser at the 1542nm
SATO Y.; MUSHA M.; NAKAGAWA K.; UEDA K.
20 Jan. 2003, レーザー学会研究会報告 = Reports on the Topical meeting of the Laser Society of Japan, 308, 19-22, Japanese, 10010260685, AA11604414

Frequency self-doubling of the cw 1-mu m lasing of a ferroelectric and ferroelastic Nd(3+):beta '-Gd(2)(MoO(4))(3) crystal with laser-diode pumping
AA Kaminskii; SN Bagaev; K Ueda; AA Pavlyuk; M Musha
A new laser with frequency self-doubling in an orthorhombic Nd(3+): beta'-Gd(2) (MoO(4))(3) crystal was constructed., TURPION LTD, Aug. 1997, QUANTUM ELECTRONICS, 27, 8, 657-658, English, Report scientific journal, 1063-7818, WOS:000071951900001

Measurement of frequency noise spectra of frequency-stabilized LD-pumped Nd:YAG laser by using a cavity with separately suspended mirrors
M Musha; S Telada; K Nakagawa; M Ohashi; K Ueda
We have developed a frequency stability system for a commercial LD-pumped Nd:YAG laser in a nonplanar ring oscillator geometry (MISER) which is used for our 20-m prototype gravitational wave detector. The frequency of the laser is locked to the rigid cavity resonance frequency, and the relative frequency noise is suppressed down to 3x10(-4) Hz/Hz(1/2), the shot-noise limited level at below 1 kHz. We are successful in evaluating the frequency noise level more accurately by means of a separately suspended mirror type cavity (4-m mode-cleaner); the noise level is 2x10(-2) Hz/Hz(1/2). As compared to a frequency noise spectrum which is locked to separately suspended mirror type cavities, the frequency noise is lower at a frequency below 400 Hz. (C) 1997 Elsevier Science B.V., ELSEVIER SCIENCE BV, Aug. 1997, OPTICS COMMUNICATIONS, 140, 4-6, 323-330, English, 0030-4018, 80009744791, WOS:A1997XG97600030

Orthorhombic gadolinium molybdate - A new nonlinear crystal for frequency doubling of one-micron cw laser emission.
AA Kaminskii; K Ueda; SN Bagaev; AA Pavlyuk; J Song; H Nishioka; N Uehara; M Musha
New nonlinear Gd-2(MoO4)(3) crystals for cw second harmonic generation of one-micron laser emission have been grown. It is shown, that the Gd-2(MoO4)(3):Nd3+ is promising candidate for cw self-doubling crystalline lasers., LEBEDEV PHYSICAL INST KVANTOVAYA ELEKTRONIKA JOURNAL, May 1996, KVANTOVAYA ELEKTRONIKA, 23, 5, 389-390, Russian, Report scientific journal, 0368-7147, WOS:A1996UT64400002

高安定マイクロ波発生のためのFigure-8型光周波数コム
山田 隆寛; 竹内裕一; 田中祐志; 栗原大周; 武者満
Oral presentation, 第71回応用物理学会春季学術講演会
22 Mar. 2024
22 Mar. 2024

衛星搭載用高安定マイクロ波発生のための1.5μmヨウ素周波数安定化レーザー
趙叡讚; 竹内裕一; 藤田悠生; 末正有; 武者満
Oral presentation, Japanese, 日本光学会年次学術講演会2023
29 Nov. 2023
27 Nov. 2023- 29 Nov. 2023

衛星搭載用高安定マイクロ波発生のための長期安定動作Figure-8型ファイバ光周波数コム
山田隆寛; 竹内裕一; 田中祐志; 栗原大周; 武者満
Oral presentation, Japanese, 日本光学会年次学術講演会2023
29 Nov. 2023
27 Nov. 2023- 29 Nov. 2023

衛星搭載用Figure-8型光周波数コムの開発
竹内裕一; 山田隆寛; 田中祐志; 栗原大周; 松下紗也; 末正有; 瀧口博士; 佐々木俊崇; 河野功; 小暮聡; 武者満
Poster presentation, Japanese, 日本光学会年次学術講演会2023
27 Nov. 2023
27 Nov. 2023- 29 Nov. 2023

音響光学素子を利用した編隊飛行衛星間相対位置・計測手法に関する実験と検証
鈴木聡宏; 五十里哲; 武者満; 中須賀真一
Oral presentation, Japanese, 第67回宇宙科学技術連合講演会
20 Oct. 2023
17 Oct. 2023- 20 Oct. 2023

衛星搭載用周波数基準のための周波数安定化光源
末正有; 松下紗也; 瀧口博士; 佐々木俊崇; 河野功; 小暮聡; 竹内裕一; 趙叡讚; 藤田悠生; 武者満
Oral presentation, Japanese, 第67回宇宙科学技術連合講演会
18 Oct. 2023
17 Oct. 2023- 20 Oct. 2023

衛星搭載用周波数基準のためのファイバ型光周波数コム
竹内裕一; 山田隆寛; 田中祐志; 栗原大周; 松下紗也; 末正有; 瀧口博士; 佐々木俊崇; 河野功; 小暮聡; 武者満
Oral presentation, Japanese, 第67回宇宙科学技術連合講演会
18 Oct. 2023
17 Oct. 2023- 20 Oct. 2023

宇宙重力波望遠鏡用のレーザー光源
武者 満
Nominated symposium, Japanese, 22th DECIGO workshop, Invited
15 Oct. 2023
15 Oct. 2023- 15 Oct. 2023

Figure-8型モード同期レーザーを用いた光周波数コムの長期動作安定性
山田 隆寛; 竹内 裕一; 田中 祐志; 栗原大周; 松下紗也; 末正有; 佐々木俊崇; 瀧口博士; 河野功; 小暮聡; 武者満
Oral presentation, 第84回応用物理学会秋季学術講演会, 応用物理学会, 熊本市民会館, Domestic conference
22 Sep. 2023
19 Sep. 2023- 23 Sep. 2023

スペース重力波アンテナDECIGO 計画(170): 光源の長期周波数安定化
藤田悠生; 趙叡讚; 竹内裕一; 末正有; 武者満
Oral presentation, 日本物理学会第78回年次大会
18 Sep. 2023
16 Sep. 2023- 19 Sep. 2023

Robust and low-phase noise all-PM figure-8 mode-locked fiber laser for spaceborne optical frequency comb
Yuichi Takeuchi; Taishu Kurihara; Takahiro Yamada; Shun Endo; Saya Matsushita; Aru Suemasa; Takatoshi Sasaki; Hiroshi Takiguchi; Isao Kawano; Satoshi Kogure; Mitsuru Musha
Poster presentation, English, CLEO-Europe 2023, Peer-reviewed
30 Jun. 2023

スペース重力波アンテナDECIGO計画(159)：1.5μmのヨウ素安定化レーザーの安定度評価
趙叡讚; 藤田悠生; 竹内裕一; 末正有; 武者満
Oral presentation, 日本物理学会2023年春季大会
24 Mar. 2023

Development of laser-optical clocks for future QZSS and experimental evaluation of a seven-satellite constellation
Saya Matsushita; Hiroshi Takiguchi; Toshitaka Sasaki; Aru Suemasa; Hideki Narita; Hideki Yamada; Kyohei Akiyama; Isao Kawano; Satoshi Kogure
Oral presentation, English, Precise Time and Time Interval Meeting (PTTI) 2023, Institute of Navigation, Long beach, CA, USA, Peer-reviewed
26 Jan. 2023
26 Jan. 2023

1.5umヨウ素安定化光源の検討
武者満
Oral presentation, Japanese, 2１th DECIGO Workshop, Invited, DEGIGO Collaborations, zoom, Domestic conference
17 Dec. 2022

精密マイクロ波発生のための衛星搭載光コム
竹内裕一; 栗原大周; 山田隆寛; 遠藤駿; 齋藤瞭太; 松下紗也; 末正有; 瀧口博士; 佐々木俊崇; 河野功; 小暮聡; 武者満
Oral presentation, Japanese, 第66回宇宙科学技術連合講演会, 日本航空宇宙学会, 熊本城ホール, Domestic conference
02 Nov. 2022

音響光学偏向子を利用した編隊飛行衛星間の高精度相対位置計測・制御
鈴木聡宏; 五十里哲; 武者満; 中須賀信一
Oral presentation, Japanese, 第66回宇宙科学技術連合講演会, 日本航空宇宙学会, 熊本城ホール, Domestic conference
01 Nov. 2022

Figure-8 type optical frequency comb for spaceborne precision microwave reference
Y.Takeuchi; T.Kurihara; T.Yamada; S.Endo; S.Matsushita; T.Sasaki; H.Takiguchi; I.Kawano; S.Kogure; M.Musha
Oral presentation, English, International Conference on Space Optics 2022 (ICSO2022), European Space Agency, Dobrovnik, Croatia, Peer-reviewed, International conference
04 Oct. 2022

人工衛星搭載用figure8型光周波数コムの開発
栗原大周; 竹内裕一; 山田隆寛; 遠藤駿; 武者満
Oral presentation, Japanese, 第83回応用物理学会秋季学術講演会, 応用物理学会, 東北大, Domestic conference
22 Sep. 2022

フェムト秒ファイバーレーザーの制御と各種応用
竹内裕一; 武者満
Oral presentation, Japanese, 日本金属学会第171回秋季講演大会, 日本金属学会, 福岡工大, Domestic conference
21 Sep. 2022

スペース重力波アンテナDECIGO計画(150):DECIGO用の光源開発
趙叡讚; 竹内裕一; 武者満; 末正有
Oral presentation, Japanese, 日本物理学会2022年秋季大会, 日本物理学会, zoom, Domestic conference
16 Sep. 2022

figure-8モード同期ファイバーレーザーの衛星搭載化検討
竹内 裕一; 遠藤 駿; 栗原大周; 齋藤 瞭太; 松下紗也; 佐々木俊崇; 瀧口博士; 河野巧; 小暮聡; 武者 満
Oral presentation, Japanese, 第69回応用物理学会春季学術講演会, 応用物理学会, zoom, Domestic conference
24 Mar. 2022

人工衛星搭載光周波数コムのためのNALM型モード同期レーザーの開発
遠藤 駿; 竹内 裕一; 栗原大周; 齋藤 瞭太; 武者 満
Oral presentation, Japanese, 第69回応用物理学会春季学術講演会, 応用物理学会, zoom, Domestic conference
24 Mar. 2022

スペース重力波アンテナDECIGO計画(141):DECIGOの光源と衛星捕捉システム
武者満; 田尻美佳; 濱口太一; 竹内裕一
Oral presentation, Japanese, 日本物理学会第77回年次大会, 日本物理学会, zoom, Domestic conference
17 Mar. 2022

Study on The Relative Position Control Method for Formation Flying Satellites Using Acousto-Optic Deflector
Toshihiro SUZUKI; Satoshi IKARI; Mitsuru MUSHA; Shinichi NAKASUKA
Oral presentation, English, International Symposium on Space Technology and Science, 日本航空宇宙学会, 別府市, International conference
26 Feb. 2022

figure-8 モード同期ファイバーレーザーを用いた光コムの開発と評価
栗原大周; 竹内 裕一; 遠藤 駿; 齋藤 瞭太; 武者 満
Oral presentation, Japanese, レーザー学会学術講演会第42回年次大会, レーザー学会, Domestic conference
12 Jan. 2022

光源と衛星捕捉システム
武者満; 田尻美佳; 濱口太一
Oral presentation, Japanese, 20th DECIGO Workshop, Invited, DEGIGO Collaborations, zoom, Domestic conference
11 Dec. 2021

光を用いた衛星搭載精密マイクロ波発生装置の開発
竹内裕一; 遠藤駿; 栗原大周; 齋藤瞭太; 武者満
Oral presentation, Japanese, 第65回宇宙科学技術連合講演会, 日本航空宇宙学会, Domestic conference
10 Nov. 2021

音響光学偏向器を用いた衛星間相対位置計測システム
武者満; 田尻美佳; 竹内裕一
Oral presentation, Japanese, 第65回宇宙科学技術連合講演会, 日本航空宇宙学会, Domestic conference
10 Nov. 2021

スペース重力波アンテナDECIGO計画(135):光源と衛星捕捉システム
武者満; 田尻美佳; 竹内裕一
Oral presentation, Japanese, 日本物理学会2021年秋季大会, 日本物理学会, zoom, Domestic conference
14 Sep. 2021

人工衛星搭載用光周波数コムの開発
遠藤駿; 竹内裕一; 栗原大周; 齋藤瞭太; 武者満
Oral presentation, Japanese, 第82回応用物理学会秋季学術講演会, 応用物理学会, zoom, Domestic conference
11 Sep. 2021

セルフスタートfigure-8モード同期レーザーの特性評価
竹内裕一; 遠藤駿; 栗原大周; 齋藤瞭太; 武者満
Oral presentation, Japanese, 第82回応用物理学会秋季学術講演会, 応用物理学会, zoom, Domestic conference
10 Sep. 2021

Long-distance Laser Positioning System by using Acousto-optic Deflector
Mitsuru Musha; Mika Tajiri; Yuichi Takeuchi
Oral presentation, English, CLEO-Europe, European Physical Society, Munich (zoom), Peer-reviewed, International conference
24 Jun. 2021

Self-started figure-8 mode-locked fiber laser for space borne optical frequency comb
Yuichi Takeuchi; Ryota Saito; Shun Endo; Mitsuru Musha
Poster presentation, English, CLEO-Europe, European Physical Society, Munich (zoom), International conference
23 Jun. 2021

Development of an all PM mode lock fiber laser for space borne frequency reference
Yuichi Takeuchi; Ryota Saito; Shun Endo; Mitsuru Musha
Oral presentation, English, International Conference on Space Optics 2020 (ICSO2020), European Space Agency, zoom, International conference
01 Apr. 2021

Laser-based satellite positioning system for space gravitational wave detector DECIGO
Mitsuru Musha; Mika Tajiri; Kei Akami; Yuichi Takeuchi
Oral presentation, English, International Conference on Space Optics 2020 (ICSO2020), European Space Agency, zoom, International conference
01 Apr. 2021

衛星搭載に向けた光周波数コムのためのFigure-8モード同期ファイバーレーザー
竹内 裕一; 齋藤 瞭太; 遠藤 駿; 栗原大周; 武者 満
Oral presentation, Japanese, 第68回応用物理学会春季学術講演会, 応用物理学会, zoom, Domestic conference
17 Mar. 2021

光を用いた衛星搭載精密マイクロ波発生装置
遠藤 駿; 竹内 裕一; 齋藤 瞭太; 栗原大周; 武者 満
Oral presentation, Japanese, 第68回応用物理学会春季学術講演会, 応用物理学会, zoom, Domestic conference
16 Mar. 2021

スペース重力波アンテナDECIGO計画(128):レーザーを用いた衛星捕捉システム
田尻美佳; 濱口太一; 竹内 裕一; 武者 満
Oral presentation, Japanese, 日本物理学会第75回年次大会, 日本物理学会, zoom, Domestic conference
14 Mar. 2021

光周波数基準を用いた衛星搭載精密マイクロ波発生装置の開発
竹内 裕一; 齋藤 瞭太; 遠藤 駿; 武者 満
Oral presentation, Japanese, レーザー学会学術講演会第41回年次大会, レーザー学会, Domestic conference
20 Jan. 2021

精密マイクロ波発生用ファイバーコムのためのFigure-8レーザーの特性評価
齋藤 瞭太; 竹内 裕一; 遠藤 駿; 武者 満
Oral presentation, Japanese, レーザー学会学術講演会第41回年次大会, レーザー学会, Domestic conference
20 Jan. 2021

AODによる衛星捕捉システムの開発状況
田尻美佳; 武者満
Oral presentation, Japanese, 19 th DECIGO Workshop, DEGIGO Collaborations, zoom, Domestic conference
21 Nov. 2020

レーザーを用いた衛星間測角・測距技術
長谷川丈紘; 田尻美佳; 竹内裕一; 武者満
Oral presentation, Japanese, 第64回宇宙科学技術連合講演会, 日本航空宇宙学会, zoom, Domestic conference
29 Oct. 2020

光を用いた精密マイクロ波周波数基準の開発
齋藤瞭太; 遠藤駿; 竹内裕一; 武者満
Oral presentation, Japanese, 第64回宇宙科学技術連合講演会, 日本航空宇宙学会, zoom, Domestic conference
28 Oct. 2020

スペース重力波アンテナDECIGO計画(122):高出力安定化光源と衛星捕捉システム
濱口太一; 長谷川丈紘; 田尻美佳; 大塚俊介; 武者満
Oral presentation, Japanese, 日本物理学会2020秋季大会, 日本物理学会, zoom, Domestic conference
15 Sep. 2020

Stable operation of a high-power Tm3+:ZBLAN fiber MOPA at 813 nm
Yuichi Takeuchi; Eiji Kajikawa; Tomohiro Ishii; Kazuhiko Ogawa; Mitsuru Musha
Oral presentation, English, Europhoton2020, European Physical Society, Prague (Zoom), International conference
04 Sep. 2020

スペース重力波アンテナDECIGO計画(113)：安定化光源と衛星捕捉システム
濱口太一; 大塚俊介; 末正有; 長谷川丈紘; 中森真輝; 赤見恵; 武者満
Oral presentation, Japanese, 日本物理学会第75回年次大会, 日本物理学会, 名古屋大学, Domestic conference
16 Mar. 2020

高出力810nm帯ファイバ増幅器における信号光フォトブリーチング
梶川詠司; 石井知広; 武者満; 小川和彦
Oral presentation, Japanese, レーザー学会学術講演会第40回年次大会, レーザー学会, 仙台国際センター, Domestic conference
22 Jan. 2020

側面研摩ZBLANファイバを用いたファイバ光学素子の開発
石井知広; 梶川詠司; 武者満; 小川和彦
Oral presentation, Japanese, レーザー学会学術講演会第40回年次大会, レーザー学会, 仙台国際センター, Domestic conference
20 Jan. 2020

Frequency stabilized lasers and applications
Mitsuru Musha
Invited oral presentation, English, Huawei workshop, Invited, Huawei, 東京 グランドプリンス新高輪, International conference
22 Nov. 2019

DECIGO用光源と衛星捕捉システム
大塚俊介; 武者満
Oral presentation, Japanese, 18 th DECIGO Workshop, DEGIGO Collaborations, 京都大学, Domestic conference
10 Nov. 2019

宇宙重力波検出器DECIGO/B-DECIGOに向けた高出力•高安定光源の開発
大塚俊介; 末正有; 中森真輝; 濱口太一; 武者満
Oral presentation, Japanese, 第63回宇宙科学技術連合講演会, 日本航空宇宙学会, アスティ徳島, Domestic conference
06 Nov. 2019

A stable watt-class Tm3+-doped ZBLAN fiber MOPA with photobleaching
Eiji Kajikawa; Tomohiro Ishii; Kazuhiko Ogawa; Mitsuru Musha
Poster presentation, English, Advanced Solid State Laser (ASSL 2019), Optical Society of America, Wiena, Austria, International conference
30 Sep. 2019

高出力810nm帯Tm3+:ZBLANカスケードファイバーMOPAの安定動作
梶川詠司; 石井知広; 小川和彦; 武者満
Oral presentation, Japanese, 第80回応用物理学会秋季学術講演会, 応用物理学会, 北海道大学, Domestic conference
21 Sep. 2019

側面研摩によるZBLANファイバカプラの開発
石井知広; 梶川詠司; 武者満; 小川和彦
Oral presentation, Japanese, 第80回応用物理学会秋季学術講演会, 応用物理学会, 北海道大学, Domestic conference
21 Sep. 2019

スペース重力波アンテナDECIGO計画(108)：B-DECIGO用高安定高出力光源の開発
大塚俊介; 濱口太一; 中森真輝; 赤見恵; 末正有; 武者満
Oral presentation, Japanese, 日本物理学会2019年秋季大会, 日本物理学会, 山形大学, Domestic conference
20 Sep. 2019

High slope efficiency and high power 813 nm Tm3+:ZBLAN fiber MOPA for the lattice laser of Sr optical lattice clock
Eiji Kajikawa; Tomohiro Ishii; Takashi Kubo; Kazuhiko Ogawa; Mitsuru Musha
Oral presentation, English, CLEO Europe 2019, European Physical Society, Munchen, Germany, Peer-reviewed, International conference
27 Jun. 2019

Japanese space gravitational wave detector DECIGO/B-DECIGO
Mitsuru Musha
Invited oral presentation, English, Gravitational Wave Advanced Detector Workshop (GWADW219), Invited, INMF Italy, Elba,Italy, International conference
21 May 2019

High power and highly-stable light source for DECIGO/B-DECIGO
Mitsuru Musha
Invited oral presentation, English, RESCEU Workshop 'Space Gravitational-Wave Detection', Invited, RESCUE, University of Tokyo, International conference
28 Mar. 2019

スペース重力波アンテナDECIGO計画(104):安定化光源と光学システム
末正有; 大塚俊介; 中森真輝; 赤見恵; 武者満
Oral presentation, Japanese, 日本物理学会第74回年次大会, 日本物理学会, 九州大学, Domestic conference
16 Mar. 2019

高出力安定動作可能なTm3+ZBLANファイバMOPA
梶川詠司; 石井知広; 久保貴司; 武者満; 小川和彦
Oral presentation, Japanese, 第66回応用物理学会春季学術講演会, 応用物理学会, 東京工業大学, Domestic conference
10 Mar. 2019

Tm3+:ZBLANファイバを用いた813nm光源の高出力安定動作
石井知広; 梶川詠司; 久保貴志; 武者満; 小川和彦
Oral presentation, Japanese, レーザー学会学術講演会第39回年次大会, レーザー学会, 東海大高輪校舎, Domestic conference
12 Jan. 2019

高出力安定化光源と衛星位置決定システムの開発
中森真輝; 武者満
Oral presentation, Japanese, 17th DECIGO Workshop, Invited, DECIGO working group, 京都大学, Domestic conference
02 Nov. 2018

宇宙重力波検出器DECIGO/B-DECIGOのための光源と光学技術の開発
大塚俊介; 末正有; 赤見恵; 中森真輝; 下奥あゆ美; 武者満
Oral presentation, Japanese, 第62回宇宙科学技術連合講演会, 日本航空宇宙学会, 久留米シティプラザ, Domestic conference
24 Oct. 2018

Novel satellite positioning system using Acousto-Optic Deflector
Mitsuru Musha; Kei Akami; Aru Suemasa
Oral presentation, English, International Conference on Space Optics 2018 (ICSO2018), European Space Agency, Chania, Greece, International conference
12 Oct. 2018

stable and high power 515-nm lasers for the space gravitational wave detector: DECIGO
Aru Suemasa; Shunsuke Ohtsuka; Ayumi Shimo-oku; Masaki Nakamori; Mitsuru Musha
Oral presentation, English, International Conference on Space Optics 2018 (ICSO2018), European Space Agency, Chania, Greece, International conference
09 Oct. 2018

Optical frequency comb applications for large missions
Mitsuru Musha
Oral presentation, English, Ultrafast Light 2018, Invited, Lebedev Physical Institute, Moscow, Russia, International conference
02 Oct. 2018

Fiber-based trapping laser for Sr optical lattice clock
Eiji Kajikawa; Mitsuru Musha
Oral presentation, English, 5th MIPT-UEC-LPI International Workshop on Atomic, Molecular, Optical Physic, Lebedev Physical Institute, Moscow, Russia, International conference
01 Oct. 2018

Optical technologies for space gravitational wave detector
Mitsuru Musha
Oral presentation, English, 5th MIPT-UEC-LPI International Workshop on Atomic, Molecular, Optical Physic, Invited, Lebedev Physical Institute, Moscow, Russia, International conference
01 Oct. 2018

813 2nm Tm3+:ZBLANファイバMOPAの高効率・高出力化
石井知広; 梶川詠司; 久保貴志; 武者満; 小川和彦
Oral presentation, Japanese, 第79回応用物理学会秋季学術講演会, 応用物理学会, 名古屋国際会議場, Domestic conference
19 Sep. 2018

スペース重力波アンテナDECIGO計画(95)：高出力・安定光源
中森真輝; 末正有; 下奥あゆ美; 大塚俊介; 中川賢一; 武者満
Oral presentation, Japanese, 日本物理学会2018年秋季大会, 日本物理学会, 信州大学, Domestic conference
16 Sep. 2018

スペース重力波アンテナDECIGO計画(96)：音響光学偏向子を用いた衛星位置決定システムの開発
赤見恵; 末正有; 武者満
Oral presentation, Japanese, 日本物理学会2018年秋季大会, 日本物理学会, 信州大学, Domestic conference
16 Sep. 2018

High efficient dual-wavelength-pumped (1050+1220nm) Tm3+-doped ZBLAN fiber MOPA at 813 nm
Eiji Kajikawa; Takashi Kubo; Tomohiro Ishii; Yu-ichi Takeuchi; Mitsuru Musha
Oral presentation, English, EuroPhoton 2018, European Physical Society, Barcelona, Spain, International conference
07 Sep. 2018

Ultrahigh stable light source for DECIGO
Mitsuru Musha; Aru Suemasa; Ayumi Shimo-oku; Shunsuke Ohtsuka
Oral presentation, English, 15th Marcel Grossmann Meeting, Invited, University of Rome "La Sapienza", Rome, Italy, International conference
01 Jul. 2018

スペース重力波アンテナDECIGO計画(92):安定化光源
下奥あゆ美; 末正有; 武者満; 中川賢一
Oral presentation, Japanese, 日本物理学会第73回年次大会, 日本物理学会, 東京理科大, Domestic conference
25 Mar. 2018

813nm Tm3+:ZBLANファイバーMOPAの2波長励起
梶川詠司; 久保貴志; 竹内裕一; 武者満; 小川和彦
Oral presentation, Japanese, 第65回応用物理学会春季学術講演会, 応用物理学会, 早稲田大学, Domestic conference
17 Mar. 2018

誘導ラマン散乱を用いた2波長励起システムによる810nm帯Tm:ZBLANファイバMOPAの高効率化
久保貴志; 梶川詠司; 竹内裕一; 河野健太; 武者満
Oral presentation, Japanese, レーザー学会学術講演会第38回年次大会, レーザー学会, 京都市勧業館みやこめっせ, Domestic conference
25 Jan. 2018

DECIGOのための安定化光源と衛星位置決定技術の開発
下奥あゆ美
Oral presentation, Japanese, 16th DECIGO Workshop, Invited, DECIGO working group, 京都大学, Domestic conference
12 Nov. 2017

宇宙重力波検出器DECIGO/B-DECIGOのための高出力・高安定光源の開発
下奥あゆ美; 末正有; 武者満
Oral presentation, Japanese, 第61回宇宙科学技術連合講演会, 日本航空宇宙学会, 新潟 朱雀メッセ, Domestic conference
25 Oct. 2017

音響光学偏向子を用いた衛星ポジショニングシステムの開発
赤見恵; 末正有; 武者満
Oral presentation, Japanese, 第61回宇宙科学技術連合講演会, 日本航空宇宙学会, 新潟 朱雀メッセ, Domestic conference
25 Oct. 2017

スペース重力波アンテナDECIGO計画(85):安定化光源
末正有; 下奥あゆ美; 中川賢一; 武者満
Oral presentation, Japanese, 日本物理学会2017年秋季大会, 日本物理学会, 宇都宮大学, Domestic conference
14 Sep. 2017

スペース重力波アンテナDECIGO計画(86):音響光学素子を用いた衛星捕捉システムの開発
赤見恵; 末正有; 武者満
Oral presentation, Japanese, 日本物理学会2017年秋季大会, 日本物理学会, 宇都宮大学, Domestic conference
14 Sep. 2017

宇宙重力波検出器DECIGOのための周波数・強度安定化光源の開発
末正有; 下奥あゆ美; 中川賢一; 武者満
Oral presentation, Japanese, 第78回応用物理学会秋季学術講演会, 応用物理学会, 福岡国際会議場, Domestic conference
05 Sep. 2017

Developments of highly frequency and intensity stabilized lasers for space gravitational wave detector :DECIGO
Aru Suemasa; Ayumi Shimo-oku; Ken'ichi Nakagawa; Mitsuru Musha
Oral presentation, English, CLEO-Europe 2017, European Physical Society, International conference
29 Jun. 2017

Frequency-stabilized lasers & their applications -from X-FEL to gravitational wave detection-
Mitsuru Musha
Invited oral presentation, English, Ginzburg Centennial Conference on Physics, Invited, Lebedev Physical Institute, Moscow, Russia, International conference
30 May 2017

Developments of highly frequency and intensity stabilized lasers for space gravitational wave detector
Aru Suemasa; Ayumi Shimo-oku; Mitsuru Musha
Poster presentation, English, 4th MIPT-LPI-UEC Joint Workshop on Atomic, Molecular, Optical Physic, Moscow Institute of Physics and Technology Univ. of Electro-communications Lebedev Physical Institute, UEC Tokyo, International conference
27 Mar. 2017

Developments of optical frequency comb for dual-comb spectroscopy and high precision frequency reference
Youhei Saito; Kana Matsusaka; Mitsuru Musha
Poster presentation, English, 4th MIPT-LPI-UEC Joint Workshop on Atomic, Molecular, Optical Physic, Moscow Institute of Physics and Technology Univ. of Electro-communications Lebedev Physical Institute, UEC Tokyo, International conference
27 Mar. 2017

スペース重力波アンテナDECIGO計画(80):安定化光源
下奥あゆ美; 末正有; 中川賢一; 武者満
Oral presentation, Japanese, 日本物理学会第72回年次大会, 日本物理学会, 大阪大学豊中キャンパス, Domestic conference
18 Mar. 2017

Highly stabilized lasers for space gravitational wave detector
Aru Suemasa; Mitsuru Musha
Poster presentation, English, CIAiS International Symposium, 最先端融合科学イノベーション教育研究コンソーシアム, 東京大学, International conference
07 Feb. 2017

DECIGOのための安定化光源
末正 有
Oral presentation, Japanese, 15th DECIGO Workshop, Invited, DECIGO working group, 東京大学(本郷), Domestic conference
05 Nov. 2016

Space gravitational wave detector DECIGO/B-DECIGO
Mitsuru Musha
Oral presentation, English, International Conference on Space Optics (ICSO2017), European Space Agency (ESA), Biarrits, France, International conference
20 Oct. 2016

Developments of highly frequency and intensity stabilized lasers for space gravitational wave detector DECIGO/B-DECIGO
Aru Suemasa; Ayumi Shimo-oku; Ken'ichi Nakagawa; Mitsuru Musha
Oral presentation, English, International Conference on Space Optics (ICSO2017), European Space Agency (ESA), Biarrits, France, International conference
18 Oct. 2016

スペース重力波アンテナDECIGO計画(75):安定化光源
末正有; 下奥あゆ美; 中川賢一; 武者満
Oral presentation, Japanese, 日本物理学会2016年秋季大会, 日本物理学会, 宮崎大学, Domestic conference
24 Sep. 2016

超高精度光干渉計を用いた重力波の直接検出
武者満
Invited oral presentation, Japanese, 電子情報通信学会, Invited, 電子情報通信学会, 北海道大学, Domestic conference
20 Sep. 2016

ロッド型フォトニック結晶ファイバーのモード不安定性の観測
北村俊幸; コスロービアン・ハイク; 椿本孝治; 吉田英次; 武者満
Oral presentation, Japanese, 第77回応用物理学会秋季学術講演会, 応用物理学会, 朱雀メッセ、新潟, Domestic conference
13 Sep. 2016

宇宙重力波望遠鏡(DECIGO)のための高出力・高安定光源の開発
下奥あゆ美; 末正有; 武者満
Oral presentation, Japanese, 第60回宇宙科学技術連合講演会, 日本航空宇宙学会, 函館アリーナ, Domestic conference
08 Sep. 2016

Developments of highly-stabilized lasers for DECIGO/Pre-DECIGO
Aru Suemasa; Ayumi Shimo-oku; Mitsuru Musha; DECIGO working group
Poster presentation, English, 11th International LISA Symposium, ETH ZUrich, University of Zurich, University of Zurich, Zurich, Switzerland, International conference
05 Sep. 2016

重力波天文学の幕開け
武者 満
Oral presentation, Japanese, 精密周波数委員会, Invited, 精密周波数委員会, 産総研, Domestic conference
22 Jun. 2016

SPACE重力波アンテナDECIGO計画(70):安定化光源
末正有; 下奥あゆ美; 中川賢一; 武者満; DECIGOワーキンググループ
Oral presentation, Japanese, 日本物理学会第71回年次大会, 日本物理学会, 東北学院大, Domestic conference
21 Mar. 2016

Development of trapping light source for Sr optical lattice clock by using Tm3+ doped fluaride fiber MOPA
梶川詠司; 久保貴志; 竹内裕一; 河野健太; 武者満
Oral presentation, Japanese, レーザー学会学術講演会第36回年次大会, レーザー学会, 名城大学, Domestic conference
11 Jan. 2016

大型研究プロジェクトの鍵となる超高安定化レーザー
武者 満
Invited oral presentation, Japanese, 日本光学会OPN(Optics for Photonic Network)研究会5, Invited, 日本光学会, 兵庫県, Domestic conference
06 Nov. 2015

Frequency-stabilized Laser and their Applications
Mitsuru Musha
Invited oral presentation, English, III MIPT-UEC Workshop on optics, atomic and molecular physics, Invited, Moscow Institute of Physics and Technologies, Lebedev Institute, Moscow, Russia, International conference
21 Oct. 2015

Fiber mode-lock laser based optical frequency comb
Naoya Matsumaru
Oral presentation, English, III International Workshop MIPT-UEC: Atomic Molecular and Optical Physics, Moscow Institute of Physics and Technology, P.N.Levedev Physical Institute, Moscow, Russia, International conference
21 Oct. 2015

An 813-nm stable trapping light source for Sr optical lattice clock with Tm-doped fluoride fiber amplifier
Eiji Kajikawa
Oral presentation, English, III International Workshop MIPT-UEC: Atomic Molecular and Optical Physics, Moscow Institute of Physics and Technology, P.N.Levedev Physical Institute, Moscow, Russia, International conference
21 Oct. 2015

Frequency-stabilized lasers and their applications
Mitsuru Musha
Invited oral presentation, English, III International Workshop MIPT-UEC: Atomic Molecular and Optical Physics, Invited, Moscow, Russia, International conference
21 Oct. 2015

安定化レーザー光源
末正有; 武者満
Oral presentation, Japanese, 14th DECIGO workshop, Invited, DECIGO working group, 京都大学, Domestic conference
18 Oct. 2015

宇宙重力波検出器用周波数・強度安定化レーザーの開発
末正有; 中川賢一; 武者満; DECIGOワーキンググループ
Oral presentation, Japanese, 第59回宇宙科学技術連合講演会, 日本航空宇宙学会, かごしま県民交流センター, Domestic conference
09 Oct. 2015

Frequency-stabilized laser for the space gravitational wave detector DECIGO
Mitsuru Musha; Aru Suemasa; Ken'ichi Nakagawa
Oral presentation, Japanese, 日本物理学会2015年秋季大会, 日本物理学会, 大阪市立大学, Domestic conference
28 Sep. 2015

A single-frequency narrow-linewidth Tm3+ dioed fluoride MOPA at 813 nm
Eiji Kajikawa; Yu-ichi Takeuchi; Kenta Kohno; Ken'ichi Nakagawa; Mitsuru Musha
Oral presentation, Japanese, 第76回応用物理学会秋季学術講演会, 応用物理学会, 名古屋国際会議場, Domestic conference
13 Sep. 2015

A Watt-class narrow-linewidth MOFPA system at 813 nm by usinga Tm3+-doped fluoride fiber amplifier for the Sr optical lattice clock
Eiji Kajikawa; Yu-ichi Takeuchi; Kenta Kohno; Ken'ichi Nakagawa; Mitsuru Musha
Oral presentation, English, CLEO Europe 2015, European Physical Society, OSA, Munich, Germany, International conference
25 Jun. 2015

SPACE重力波アンテナDECIGO計画(61)安定化光源
末正有; 中川賢一; 武者満
Oral presentation, Japanese, 日本物理学会第70回年次大会, 日本物理学会, 早稲田大学, Domestic conference
21 Mar. 2015

Tm3+:ZBLANファイバMOPAによる810nm帯高輝度狭線幅光源の開発
梶川詠司; 竹内裕一; 河野健太; 中川賢一; 武者満
Oral presentation, Japanese, レーザー学会学術講演会35回年次大会, レーザー学会, 東海大高輪校舎, Domestic conference
11 Jan. 2015

宇宙重力波用検出器用周波数安定化レーザーの開発
末正有; 中川賢一; 武者満
Oral presentation, Japanese, 第58回宇宙科学技術連合講演会, 日本航空宇宙学会, 長崎ブリックホール, Domestic conference
12 Nov. 2014

安定化レーザー光源
末正有; 武者満
Oral presentation, Japanese, 13th DECIGO workshop, Invited, DECIGO working group, 京都大学, Domestic conference
24 Oct. 2014

Highly frequency-stabilized laser for gravitational Wave detector DECIGO/DPF
Aru Suemasa; Ken'ichi Nakagawa; Mitsuru Musha
Oral presentation, English, International Conference on Space Optics (ICSO) 2014, European Space Agency (ESA), Tenerife, Spain, International conference
09 Oct. 2014

Japanese Space Gravitational Wave antenna DECIGO and DPF
Mitsuru Musha; DECIGO collaborations
Oral presentation, English, International Conference on Space Optics (ICSO) 2014, European Space Agency (ESA), Tenerife, Spain, International conference
08 Oct. 2014

Sr光格子時計用813nm帯狭線幅Tm3+:ZBLANファイバMOPAの開発
梶川詠司; 竹内裕一; 河野健太; 中川賢一; 武者満
Oral presentation, Japanese, 第75回応用物理学会秋季学術講演会, 北海道大学, Domestic conference
19 Sep. 2014

宇宙重力波検出器DPFのための周波数安定化光源
末正有; 中川賢一; 武者満
Oral presentation, Japanese, 第75回応用物理学会秋季学術講演会, 北海道大学, Domestic conference
18 Sep. 2014

775nm励起Tm3+:ZBLANファイバによる813nm光増幅
竹内裕一; 梶川詠司; 河野健太; 中川賢一; 武者満
Oral presentation, Japanese, 第75回応用物理学会秋季学術講演会, 北海道大学, Domestic conference
18 Sep. 2014

Tm3+添加フッ化物ファイバMOPAによるSr光格子時計トラップ光源の開発
竹内裕一; 梶川詠司; 中川賢一; 武者満
Oral presentation, Japanese, 第5回精密周波数委員会, 精密周波数委員会, NDK千歳テクニカルセンター, Domestic conference
15 Sep. 2014

813-nm narrow linewidth light sources for Sr optical lattice clock based on Tm-doped fluaride fiber amplifier
Yu-ichi Takeuchi; Eiji Kajikawa; Kenta Kohno; Ken'ichi Nakagawa; Mitsuru Musha
Oral presentation, English, 6th EPS-QEOD Europhoton conference, European Physical Society, Neuchatel, Switzerland, International conference
26 Aug. 2014

スペース重力波アンテナDECIGO計画(54)安定化光源
末正有 武者満; 中川賢一; 植田憲一
Oral presentation, Japanese, 日本物理学会第69回年次大会, 日本物理学会, 東海大学湘南キャンパス, Domestic conference
28 Mar. 2014

Development of the light source for DPF
Mitsuru Musha; Aru Suemasa; Ken'ichi Nakagawa; Ken-ichi Ueda
Oral presentation, Japanese, 第57回宇宙科学技術連合講演会,第57回宇宙科学技術連合講演会
Oct. 2013

A Space-borne frequency-stabilized laser for the space gravitationalwave detector: DPF
Mitsuru Musha; Aru Suemasa; Ken'ichi Nakagawa; Ken-ichi Ueda
Oral presentation, English, AP-RASC 2013, URSI, Taipei, Taiwan, International conference
05 Sep. 2013

Tm:ZBLANファイバ増幅器を用いた狭線幅813nm光源の開発
竹内裕一; 河野健太; 武者満; 中川賢一; 植田憲一
Oral presentation, Japanese, 第74回応用物理学会秋季学術講演会,応用物理学会
Sep. 2013

スペース重力波アンテナDECIGO計画：安定化光源
武者満; 末正有; 中川賢一; 植田憲一; DECIGOワーキンググループ
Oral presentation, Japanese, 日本物理学会2013秋季大会,日本物理学会
Sep. 2013

Development of an 813-nmTm-doped ZBLAN fiber amplifier for the Sr optical lattice clock
Yu-ichi Takeuchi; Masanori Uehara; Kenta Kohno; Mitsuru Musha; Ken'ichi Nakagawa; Ken-ichi Ueda
Oral presentation, English, CLEO Europe 2013, European Physical Society, Munich, Germany, International conference
15 May 2013

光周波数基準-超高安定化レーザーと精密光リンク-
武者 満
Oral presentation, Japanese, 第5回光ネットワーク産業・技術研究会, Invited, 光ネットワーク産業技術研究会, 産総研臨界センター, Domestic conference
11 Mar. 2013

KAGRA用高性能ミラー評価:散乱角度分布測定装置の開発
長岡慧; 武者満; 辰巳大介; 上田暁俊; 三尾典克; 米田仁紀; 植田憲一
Oral presentation, Japanese, 日本物理学会2013春季大会,日本物理学会2013春季大会
Mar. 2013

光周波数標準-超高安定化光源と精密光リンク
武者満
Invited oral presentation, Japanese, 第5回光ネットワーク産業・技術研究会, 情報通信研究機構
Mar. 2013

小型重力波観測衛星 ＤＰＦのための周波数安定化光源の開発
武者満; 末正有; 加納尚樹; 中川賢一; 植田憲一
Oral presentation, Japanese, 第56回宇宙科学技術連合講演会,第56回宇宙科学技術連合講演会
Nov. 2012

Developments of a space-borne stabilized laser for DECIGO and DPF
Mitsuru Musha; Ken'ichi Nakagawa; Ken-ichi Ueda
Oral presentation, English, ICSOS 2012, European space agency, NICT, Ajaccio, Corsica, France, International conference
09 Oct. 2012

Developments of a space-borne stabilized laser for DPF II
M.Musha; K.NAKAGAWA; K.UEDA
Oral presentation, Japanese, 日本物理学会,日本物理学会2012秋季大会
Sep. 2012

Developments of the fiber optical frequency comb for precision spectroscopy
T.Kitamura; N.Watanabe; A.Nagaku; M.Musha; K.Nakagawa; K.Ueda
Oral presentation, Japanese, 第73回応用物理学会学術講演会,第73回応用物理学会学術講演会
Sep. 2012

Developments of 813nm Tm:ZBLAN fiber amplifier for Sr optical lattice clock
M.Musha; K.Kohno; Y.Takeuchi; T.Kitamura; K.Nakagawa; K.Ueda
Oral presentation, Japanese, 第73回応用物理学会学術講演会,第73回応用物理学会学術講演会
Sep. 2012

DPFのための衛星搭載用高安定化光源の開発
長久敦史; 武者満; 中川賢一; 植田憲一
Oral presentation, Japanese, 日本物理学会,日本物理学会
Sep. 2011

Precision Timing and RF Signal Distribution for XFEL by Delivering Optical Frequency Comb through Length-stabilized Fiber
Mitsuru Musha; Toshio Ryuo; Ken-ichi Nakagawa; Ken-ichi Ueda
Oral presentation, English, URSI-GASS 2011
Aug. 2011

Developments of optical frequency reference based on a fs fiber comb II
T.Kitamura; A.Nagaku; M.Musha; K.Nakagawa; K.Ueda
Oral presentation, Japanese, 第72回応用物理学会学術講演会
Aug. 2011

A Highly-stabilized Light Source for the Space Gravitational Wave Detector DECIGO and DPF
Mitsuru Musha; Shin-ya Horiuchi; Ken'ichi Nakagawa; Ken-ichi Ueda
Oral presentation, English, CLEO-Europe 2011
May 2011

Developments of the Light Source for DECIGO and DPF
Mitsuru Musha; Ken'ichi Nakagawa; Ken-ichi Ueda
Oral presentation, English, ICSOS2011
May 2011

Developments of the light source for DPF
Shin-ya Horiuchi; Mitsuru Musha; ken'ichi Nakagawa; Ken-ichi Ueda
Oral presentation, Japanese, 日本物理学会,第66回年次大会
Mar. 2011

Developments of light sources for DECIGO and DPF
M.Musha; S.Horiuchi; T.Kitamura; K.Nakagawa; K.Ueda
Oral presentation, Japanese, 第10回宇宙科学シンポジウム,第10回宇宙科学シンポジウム
Jan. 2011

The precision optical frequency dissemination system and its applications
M.Musha; K.Nakagawa; K.Ueda
Invited oral presentation, Japanese, レーザー学会第31回年次会光拠点シンポジウム, レーザー学会
Jan. 2011

Developments of the light source for DECIGO and DPF
M.Musha; S.Horiuchi; K.Nakagawa; K.Ueda
Oral presentation, Japanese, 日本航空宇宙学会,第54回宇宙科学技術連合講演会
Nov. 2010

Developments of the light source for DECIGO/DPF V
S.Horiuchi; T.Kitamura; M.Musha; K.Nakagawa; K.Ueda
Oral presentation, Japanese, 日本物理学会,日本物理学会
Sep. 2010

Developments of the precision optical frequency measurement system by using fs fiber comb
T.Kitamura; M.Musha; K.Nakagawa; K.Ueda
Oral presentation, Japanese, 応用物理学会,応用物理学会
Sep. 2010

DECIGO/DPF用高周波数安定化光源の開発(4)
堀内慎也; 中村真大; 武者満; 中川賢一; 植田憲一
Oral presentation, Japanese, 日本物理学会,日本物理学会
Mar. 2010

レーザー干渉計型宇宙重力波アンテナ(DECIGO計画)
武者満; DECIGO ワーキンググループ
Oral presentation, Japanese, 電気情報学会,電気情報学会
Mar. 2010

Developments of the frequency-stabilized laser for DECIG/DPF III
M.Nakamura; S.Horiuchi; M.Musha; K.Nakagawa; K.Ueda
Oral presentation, Japanese, 日本物理学会,日本物理学会09年秋季大会
Sep. 2009

X線自由電子レーザー用高精度RF・パルスタイミング伝送システムの開発
流王登志雄; 武者満; 中川賢一; 植田憲一
Oral presentation, Japanese, 応用物理学会,第70回応用物理学会学術講演会
Sep. 2009

Construction status of a timing and low-level RF system for XFEL/SPring-8
N.Hosoda; T.Ohshima; H.Maesaka; S.Matsubara; K.Tamasaku; M.Musha; Y.Ohtake
Oral presentation, Japanese, 日本加速器学会,第6回日本加速器学会年会
Aug. 2009

Frequency measurement of a Sr optical lattice clock using a coherent optical link over a 120 km fiber
M.Musha,F.-L.Hong; M.Takamoto; H.Inaba; S.Yanagimachi; A.Takamiawa; K.Watabe; T.Ikegami; M.Imae; Y.Fujii; M.Amemiya; K.Nakagawa; K.Ueda; H.Katori
Oral presentation, English, CLEO2009
Jun. 2009

DECIGO/DPF用の周波数安定化光源の開発(2)
中村真大; 堀内慎也; 松島隆敏; 武者満; 中川賢一; 植田憲一
Oral presentation, Japanese, 日本物理学会,第64回年次大会
Mar. 2009

Developments of the licht source for DECIGO & DPF
Mitsuru Musha; Ken'ichi Nakagawa; Ken-ichi Ueda
Oral presentation, English, 1st International LISA/DECIGO Workshop, Institute of Space and Astronautical Science, Institute of Space and Astronautical Science, Kanagawa, Japan, International conference
13 Nov. 2008

Low Level RF and Timing System for XFEL/SPRING-8
T.Oshima; N.Hosoda; H.Maesaka; K.Tamasaku; M.Musha; Y.Otake
Oral presentation, English, XXIV Linear Accelerator ConferenceF
Oct. 2008

Precision optical frequency transfer over 50km by using an urban fiber network
武者満; 中川賢一; 植田憲一; 洪鋒雷
Oral presentation, Japanese, 応用物理学会,応用物理学会
Sep. 2008

DECIGO/DPF用の周波数安定化光源の開発
中村真大; 武者満; 中川賢一; 植田憲一
Oral presentation, Japanese, 日本物理学会,日本物理学会
Sep. 2008

Precision Optical Carrier Transfer over 110km
Mitsuru Musha; Feng-Lei Hong; Ken'ichi Nakagawa; Ken-ichi Ueda
Oral presentation, English, URSI General Assembly 2008
Aug. 2008

Development of the Optical Timing and rf Distribution Systemfor XFEL/SPring-8
Y.Otake; K.Tamasaku; K.Imai; MKourogi; N.Hosoda; M.Kitamura; H.Maesaka; T.Ohshima; M.Musha
Oral presentation, English, 30th International Conference on Free Electron Laser
Aug. 2008

XFELに向けたタイミング・RF制御
大島隆; 前坂比呂和; 細田直康; 玉作賢治; 武者満; 大竹雄二
Oral presentation, Japanese, 日本加速器学会,第5回加速器学会
Aug. 2008

Coherent optical transfer via 110-km urban fiber network for freqquency measurement of 87Sr optical lattice clock
M.Musha; F-L. Hong; M.Takamoto; H. Inaba; S. Yanagimachi; A.Takayaagi; K.Watabe; T.Ikegami; Michito I.Yasuhisa; Y.Fujii; M.Amemiya; K.Nakagawa; K.Ueda; H.Katori
Oral presentation, English, CPEM2008
Jun. 2008

Fiber length stabiblization system for long-baseline phased-array radio telescope(ALMA)
Mitsuru Musha; Ken'ichi Nakagawa; Ken-ichi Ueda; Masato Ishiguro; Akitoshi Ueda
Invited oral presentation, English, CLEO2008, CLEO 2008, SanJose, International conference
May 2008

Timing and LLRF system of Japanese X-FEL to realize a few tenth of femto-second stability
Y.Otake; T.Oshima; N.Hosoda; H.Maesaka; T.Fukui; T.Ohata; M.Musha; K.Tamasaku; M.Kitamura; K.Imai.M.Kourogi; T.Shintake
Oral presentation, English, ICALEPCS 2007
Oct. 2007

長距離基準信号伝送の為のファイバ長安定化
武者満; 中川賢一; 植田憲一; 洪鋒雷
Oral presentation, Japanese, 応用物理学会,応用物理学会
Sep. 2007

DECIGO用の高安定化・高出力レーザー光源の開発
松島隆敏; 武者満; 中川賢一; 植田憲一
Oral presentation, Japanese, 日本物理学会,日本物理学会
Sep. 2007

XFEL/SPring-8の光タイミング・高周波分配システムにおけるファイバ長安定化
前坂比呂和; 細田直康; 大島隆; 玉作賢治; 武者満; 今井一弘; 興梠元伸; 大竹雄二
Oral presentation, Japanese, 日本加速器学会,第4回日本加速機学会
Aug. 2007

Robust and precision length correction of the long optical fiber for ddissemination of frequency standards
Mitsuru Musha; Ken'ich Nakagawa; Ken-ichi Ueda
Oral presentation, English, NMIJ-BIPM Workshop
May 2007

重力波検出用干渉計光源としての高品質・高出力fiber-MOPAの開発V
三浦純一; 武者満; 中川賢一; 植田憲一
Oral presentation, Japanese, 日本物理学会,日本物理学会
Sep. 2006

次世代重力波検出器用洪安定・高出力fiber-MOPAの開発
三浦純一; 武者満; 中川賢一; 植田憲一
Oral presentation, Japanese, 応用物理学会,応用物理学会
Aug. 2006

重力波検出用干渉計光源としての高品質・高出力fiber-MOPAの開発IV
三浦純一; 武者満; 中川賢一; 植田憲一
Oral presentation, Japanese, 日本物理学会,日本物理学会
Sep. 2005

長距離基準信号伝送のための高精度・高安定ファイバ長制御システムの開発
橋本並樹; 武者満; 中川賢一; 植田憲一
Oral presentation, Japanese, 応用物理学会,応用物理学会
Sep. 2005

Developments of a fiber-MOPA system for the light source of the gravitational wave antenna
J.Miura; M.Musha; K.Nakaawa; K.Ueda
Oral presentation, English, AMALDI6
Aug. 2005

光周波数コムを用いたCO分子吸収線の周波数測定
田村洋介; 佐藤洋平; 武者満; 中川賢一; 植田憲一
Oral presentation, Japanese, レーザー学会第332回研究会,レーザー学会第332回研究会
Feb. 2005

Robust and Precise Length Correction of 25-km Fiber for Distribution of Local Oscillators
Mitsuru Musha; Ken'ichi Nakagawa; Ken-ichi Ueda; Akitoshi Ueda; Masato Ishiguro
Oral presentation, English, LEOS Summer Topical Meeting 2005
2005

Generation and Distribustion of the Stable mm-wave reference signal for ALMA
MitsuruMusha,YoheiSato; Ken'ichi Nakagawa; Ken-ichi Ueda. AkitoshiUeda; MasatoIshiguro
Invited oral presentation, English, NMIJ-BIPM Workshop, NMIJ-BIPM Workshop, International conference
2005

重力波検出用干渉計光源としての高品質・高出力fiber-MOAPの開発III
武者満; 三浦純一; 中川賢一; 植田憲一
Oral presentation, Japanese, 日本物理学会,日本物理学会
Sep. 2004

周波数計測方式によるファイバー長制御システムの開発
佐藤洋平; 武者満; 中川賢一; 植田憲一
Oral presentation, Japanese, 応用物理学会,応用物理学会
Sep. 2004

重力波検出用干渉計光源としての高品質・高出力fiber-MOPAの開発II
梶原淳司; 武者満; 中川賢一; 植田憲一
Oral presentation, Japanese, 日本物理学会,日本物理学会
Mar. 2004

モードロックファイバレーザーの周波数制御とその応用
平田淳二; 武者満; 中川賢一
Oral presentation, Japanese, レーザー学会第320回研究会,レーザー学会第320回研究会
Feb. 2004

Optical generation of a highly stable mm-wave by heterodyning of two phase-locked LDs with an optical comb generator
Mitsuru Musha; Ken'ichi Nakagawa; Ken-ichi Ueda; Akitoshi Ueda; Masato Ishiguro
Oral presentation, English, CLEO2004
2004

2台のLDと光コムを用いた安定化差周波数光源の開発
武者満; 佐藤洋平; 中川賢一; 植田憲一; 上田暁俊
Oral presentation, Japanese, 応用物理学会,応用物理学会
Sep. 2003

重力波干渉計用光源としての高品質・高安定FIBER-MOPAの開発
梶原淳司; 武者満; 中川賢一; 植田憲一
Oral presentation, Japanese, 日本物理学会,日本物理学会
Sep. 2003

ファイバ長制御の為の1.5μm帯波長基準光源の開発
佐藤洋平; 武者満; 中川賢一; 植田憲一
Oral presentation, Japanese, 応用物理学会,応用物理学会
Sep. 2003

LDの差周波数を用いた安定化THz光源の開発
武者満; 佐藤洋平; 中川賢一; 植田憲一
Oral presentation, Japanese, 応用物理学会,応用物理学会
Mar. 2003

1.5μm帯アセチレン周波数安定化半導体レーザー光源の開発とその応用
佐藤洋平; 武者満; 中川賢一; 植田憲一
Oral presentation, Japanese, レーザー学会第308回研究会,レーザー学会第308回研究会
Feb. 2003

モードロックファイバーレーザーを用いたTHz帯基準信号の作製とその評価
武者満; 小林憲史; 中川賢一; 植田憲一
Oral presentation, Japanese, 応用物理学会,応用物理学会
Mar. 2002

Development of High Power and Highly-stabilized Light Source for Gravitational Wave Detector
Mitsuru Musha; Ken'ichi Nakagawa; Ken-ichi Ueda
Invited oral presentation, English, URSI General Assembly 2002, URSI General Assembly 2002, International conference
2002

コヒーレント加算Nd:YAGレーザーの強度雑音特性
武者 満; 中川賢一; 植田憲一
Oral presentation, Japanese, 日本物理学会,日本物理学会
Sep. 2001

Coherent Addtion of injection-locked Nd:YAG lasers
Mitsuru Musha; Takeshi Kanaya; Ken'ichi Nakagawa; Ken-ichi Ueda
Oral presentation, English, CLEO PR2001
Jul. 2001

コヒーレント加算によるＮd:YAGレーザーの高出力化
武者満; 金谷剛; 中川賢一; 植田憲一
Oral presentation, Japanese, 応用物理学会,応用物理学会
Sep. 2000

注入同期Nd:YAGレーザーの広帯域周波数安定化
武者 満; 中川賢一; 植田憲一
Oral presentation, Japanese, 微小光学研究会,微小光学研究会
Dec. 1999

2周波数基準を用いた注入同期Nd:YAGレーザーの周波数安定化
武者 満; 中川賢一; 植田憲一
Oral presentation, Japanese, 応用物理学会,応用物理学会
Sep. 1999

光周波数ネットワーク実現のための半導体レーザーの非線型波長変換
中川賢一; 武者 満; 洪 鋒雷; 大苗 敦; 石川 純; 依田 潤
Oral presentation, Japanese, 応用物理学会,応用物理学会
Sep. 1999

Frequency stabilized solid state laser
Mitsuru Musha; Ken-ichi Ueda
Oral presentation, Japanese, CRL International Symposium, Tokyo
Mar. 1999

注入同期Nd:YAGレーザーの広帯域周波数安定化
武者 満; 金谷 剛; 中川賢一; 植田憲一
Oral presentation, Japanese, 応用物理学会,応用物理学会
Mar. 1999

注入同期Nd:YAGレーザーの広帯域周波数安定化
武者 満; 中川賢一; 植田憲一
Oral presentation, Japanese, 応用物理学会,応用物理学会
Mar. 1999

The Interferometric Gravitational wave detector TAMA300 and the frequency-stabilized laser with high-finesse optical resonator(invited)
Mitsuru Musha; Akitoshi Ueda; Ken-ichi Ueda; Masatake Ohashi
Invited oral presentation, English, LASE'99, LASE'99, International conference
Jan. 1999

Frequency stabilized injection-locked laser
Mitsuru Musha; Takeshi Kanaya; Ken'ichi Ueda
Oral presentation, English, AHPLA '99
1999

A Highly Frequency -stabilized Injection-locked Nd:YAG Laser for the Light Source of a gravitaional Wave Antenna
Mitsuru Musha; Ken'ichi Nakagawa; Ken-ichi Ueda
Oral presentation, English, 13th International Conference on Laser Spectroscopy
1997

Coherent Addtion of injection-locked Nd:YAG lasers
M.Musha; T.Kanaya; K.Nakagawa; K.Ueda
Oral presentation, English, CLEO/Pacific Rim'97
1997

Development of highly stabilized laser for gravitaional wave detection
Mitsuru Musha; Ken-ichi Ueda; Ken'ichi Ueda
Oral presentation, English, TAMA Workshop on Gravitational wave detection, 国立天文台, 国立女女性教育会館、埼玉, Domestic conference
12 Nov. 1996

重力波検出の為のレーザーの高安定化II
武者満; 中川賢一; 植田憲一
Oral presentation, Japanese, 日本物理学会,日本物理学会
Sep. 1996

重力波検出の為のレーザーの高安定化
武者満; 中川賢一; 植田憲一
Oral presentation, Japanese, 日本物理学会,日本物理学会
Mar. 1996

Development of all-semiconductor laser sources for studies of 88Sr+ ions confined in RF trap
M.Musha; A.Zvyagin; K.Nakagawa; M.Ohtsu
Oral presentation, English, International Symposium on Atomic Frequency Standards and Quantum Electronics
1993

基礎電磁気および演習
The University of Electro-Communications

基礎電磁気および演習
電気通信大学

情報理工学基礎輪講
The University of Electro-Communications

情報理工学基礎輪講
電気通信大学

先端工学基礎輪講
The University of Electro-Communications

先端工学基礎輪講
電気通信大学

基盤理工学専攻基礎
The University of Electro-Communications

基盤理工学専攻基礎
The University of Electro-Communications

基盤理工学専攻基礎
電気通信大学

総合コミュニケーション科学
The University of Electro-Communications

総合コミュニケーション科学
The University of Electro-Communications

総合コミュニケーション科学
電気通信大学

電気回路第１
The University of Electro-Communications

電気回路第１
The University of Electro-Communications

電気回路第１
電気通信大学

光エレクトロニクスコース実験第2
The University of Electro-Communications

光エレクトロニクスコース実験第2
The University of Electro-Communications

光エレクトロニクスコース実験第2
電気通信大学

光工学実験第2
The University of Electro-Communications

光工学実験第2
電気通信大学

情報光工学特論
The University of Electro-Communications

基礎電気回路
The University of Electro-Communications

情報光工学特論
The University of Electro-Communications

情報光工学特論
電気通信大学

基礎電気回路
The University of Electro-Communications

基礎電気回路
電気通信大学

日本物理学会

応用物理学会

レーザー学会

高安定レーザーを用いた測位衛星搭載時計の基盤技術開発
武者 満; 竹内 裕一
国立研究開発法人宇宙航空研究開発機構, 有償共同研究, 国立研究開発法人宇宙航空研究開発機構, Coinvestigator, YC2023089
Nov. 2023 - Feb. 2024

宇宙重力波干渉計の地上試験モデルの完成
中村卓史
宇宙重力波検出器DECIGOを実現するための要素技術の開発を目指す。この内で、基幹技術の１つである衛星搭載用超周波数安定化光源の研究を行う
01 Apr. 2015 - 31 Mar. 2020

高精度加速度計及び光周波数基準の研究開発
武者 満
国立研究開発法人宇宙航空研究開発機構, 国立研究開発法人宇宙航空研究開発機構, 共同研究, Principal investigator
2019

XFEL/SPring-8"SACLA"のレーザータイミングシステムの高度化
武者 満
理化学研究所高輝度光科学研究センター, 理化学研究所高輝度光科学研究センター, Coinvestigator
Apr. 2013 - Mar. 2017

重力波観測望遠鏡 Pre-DECIGO のミッション検討
安東正樹
JAXA, 研究助成
01 Apr. 2015 - 31 Mar. 2016

小型科学衛星戦略的開発経費 小型重力波観測衛星DPFのミッション検討
安東正樹
JAXA, 研究助成, 宇宙重力波検出器DECIGOの前哨衛星DPFを開発するための検討と研究開発にかんする助成である この経費で衛星搭載用周波数安定化光源の開発を進める
01 Apr. 2014 - 31 Mar. 2015

香取創造時空間プロジェクト
武者 満
ERATO 戦略的創造研究推進事業, 科学技術振興機構, Coinvestigator not use grants
Nov. 2010 - Mar. 2015

小型科学衛星戦略的開発経費 小型重力波観測衛星DPFのミッション検討
安東正樹
JAXA, 研究助成, 宇宙重力波検出器DECIGOの前哨衛星DPFを開発するための検討と研究開発にかんする助成である この経費で衛星搭載用周波数安定化光源の開発を進める
01 Apr. 2013 - 31 Mar. 2014

小型科学衛星戦略的開発経費 小型重力波観測衛星DPFのミッション検討
安東正樹
JAXA, 研究助成, 宇宙重力波検出器DECIGOの前哨衛星DPFを開発するための検討と研究開発にかんする助成である この経費で衛星搭載用周波数安定化光源の開発を進める
01 Apr. 2012 - 31 Mar. 2013

Research and development of high-power, high-repetition rate, ultrashort pulse Yb-doped ceramic lasers
UEDA Ken-ichi; MUSHA Mitsuru; SHIRAKAWA Akira; DONG Jun; KOUZNETSOV Dmitrii
Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, The University of Electro-Communications, Grant-in-Aid for Scientific Research (A), We studied laser-diode-pumped femtosecond Yb-doped ceramic lasers for shorter pulse durations and higher powers. The success of Kerr-lens mode locking by use of sesquioxides (Re_2O_3, Re=Y, Lu, Sc) enables short-pulse mode-locking beyond general bandwidth limitations. For example, 92fs pulses with 850mW of output power from Yb:Sc_2O_3 was achieved. Ceramic lasers with multiple ceramics in a single resonator were also investigated. Broadening the gain bandwidth by use of Yb:Y_2O_3 and Yb:Sc_2O_3 simultaneously realized an output of 53fs and 1W, the record shortest pulse generation directly from an Yb solid-state oscillator. The series of our results show the powers and efficiencies are far beyond other materials in a sub-100fs region, and advanced the specifications of Yb solid-state lasers significantly. In addition, we have developed various composite ceramics and demonstrated a self-Q-switched microchip laser with 237ps of pulse duration, 172μJ of pulse energy, and 0.72MW of peak power by Yb:YAG/Cr:YAG. For the development of temperature-tuned high-power active-mirror lasers, we investigated systematically the spectroscopic, thermal, and mechanical properties of YAG and Re_2O_3 ceramics. We developed a model including the temperature dependences of the stimulated emission cross section, population distribution within manifolds, temperature distribution in a gain medium and concentration quenching, and established how we optimally extract the energy from a temperature-tuned Yb:YAG laser. Higher-doping in a thinner medium is effective for power scaling of active-mirror lasers. We discovered, however, that when highly Yb-doped materials are pumped strongly, they are excited to a charge-transfer band by cooperative up-conversion and ultra-broadband emission is generated, giving the limitation. In highly Yb-doped Yb:YAG lasers, ceramics showed higher efficiency than single crystals, and as high as 60.6% Slope efficiency was obtained by 20% Yb:YAG. We can conclude that ceramics are suitable than single crystals for high doping since ceramics will have less impurity and hence the aforementioned nonlinear loss., 17204034
2005 - 2007

Coherent control of laser arrays by complex resonator
SHIRAKAWA Akira; UEDA Ken-ichi; MUSHA Mitsuru
Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, The University of Electro-Communications, Grant-in-Aid for Scientific Research (B), We have proposed and demonstrated highly efficient coherent beam combining of fiber lasers and laser diodes by Y-shaped array coupled with fused fiber couplers. Near-field coupling of N fiber lasers by use of N×N fused fiber couplers enables a power-summed output from one of N fiber ports without any fiber-length adjustment. The wavelengths satisfying constructive interference have the highest effective reflectivities and are selectively excited as a coherently-added single beam output. High addition efficiencies of 94, 96, and 85% have been obtained for N=2, 4, and 8 erbium-doped fiber lasers, respectively. The measured frequency characteristics of the coupled array well matched with the theory. The measured array-number dependence of the addition efficiency is well matched with the simple-scaling theory we developed. The clarified limit of coherent addition (N=8〜10) is found to be an inherent problem in length-different laser arrays. The characteristic bandwidth narrowing by the Vernier effect can be applied to high-power, narrowband fiber laser beyond nonlinearity limitations. By threshold control of the supermodes, high-speed (>1 kHz), high-contrast-ratio (>100) coherent control of beam direction has been demonstrated. We also proposed that harmonic mode locking can be attained by coupling ultrafast lasers. In a preliminary experiment, 20-th harmonic sub-picosecond pulse train with >40-dB mode suppression ratio has been successfully obtained. In conclusion, it has been shown that coherent arraying of multiple lasers realizes not only power and brightness scaling but various new-functionality lasers., 15340132
2003 - 2005

Research for high-power femtosecond Yb^<3+>:Y_2O_3 ceramic laser
UEDA Ken-ichi; MUSHA Mitsuru; SHIRAKAWA Akira; YANAGITANI Takagimi
Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, The University of Electo-Communications, Grant-in-Aid for Scientific Research (B), Based on knowledge and technologies accumulated in the development of ceramic YAG laser, we started investigation of a new material Y_2O_3 (yttria) with further potentials for lasers. Yb^<3+>:Y_2O_3 is a new laser material enabling higher thermal conductivity, broader bandwidth, and shorter pulse generation than YAG. However, its high melting temperature of 2430℃ has made difficulty on crystal growth. By applying our novel fabrication method of laser ceramics based on nanocrystalline technology, Y_2O_3 ceramic was fabricated at a sintering temperature of 1700℃, which is lower than the phase-transition temperature of 2280℃ and then high-quality laser material was successfully obtained with a large size. We have demonstrated CW laser oscillation of Yb:Y_2O_3 with as high as a 9.2-W power and 72% efficiency by laser-diode (LD) end-pumping and thus given evidence of its excellent property as a laser material. Passive mode-locking by semiconductor saturable-absorber mirrors was successfully demonstrated and transform-limited, 430-fs pulses with as high as a 420-mW average power were generated. We also succeeded in mode-locking by a GaAs saturable-absorber and enabled LD-direct pumped femtosecond solid-state laser. On the way of laser developments, we have investigated spectroscopic, thermal, and mechanical properties of YAG and Y_2O_3. It was then experimentally proved that a polycrystalline ceramic laser material has a more than three times higher thermal shock parameter than a single crystal, which is suitable for high-dense pumping and high-power lasers. The characteristic size scalability and strong fracture toughness of ceramic lasers are of significance for fusion drivers because their operation limits are determined by thermal shock parameters of the gain materials. We also developed composite ceramics. It was found that the diffusion distances of doped ions are more than fiver times longer than those by conventional diffusion bonding, and the mechanical strength of the ceramic bonding is as high as that in a bulk ceramic. Both indicate the perfect bonding of composite ceramics. Investigation of new materials such as other sesquioxides Sc_2O_3 and Lu_2O_3 have also started. These Yb-doped materials have broad emission spectra like Yb:Y_2O_3. It was found that Yb:Lu_2O_3 will be promising for high average power femtosecond laser because of the higher thermal conductivity even under doping., 14340120
2002 - 2004