Reseach
Distributed Reflector (DR) laser with Deeply-Etched Vertical Gratings
Stable single-mode semiconductor lasers operating around 1.5 μm is of importance for optical communication system. Distributed FeedBack (DFB) or distributed Bragg Reflector (DBR) structures has been usually employed to select single longitudinal mode. An advanced type of single mode laser, the distributed reflector (DR) laser, has been developed to improve the performance of DFB or DBR laser. In the early stage of development of DR lasers, however, several repetitions of etching and regrowing steps were indispensable for fabricating gratings parallel to the epitaxial junction plane. Recently, it has been proposed that a periodic grating on both sidewalls of the mesa, i.e., a vertical grating (VG), can replace the conventional one. Since the diffraction grating and mesa structure are fabricated simultaneously, the number of processing steps is greatly reduced. Furthermore, deeply etched DBR mirrors can be patterned without further complication of the process. Experimentally, it has already been verified that VG on narrow stripe can provide sufficient feedback along both active and passive devices.
The sample with the cavity length of 150 μm, stripe width of 1.3μm and grating depth of 70 nm on both lateral sides exhibited a threshold current of 2.8 mA, a differential quantum efficiency of 28% from the cleaved front facet under CW condition. In the same device, submode suppression ratio of 44dB was achieved at a bias current of five times the threshold.
　
List of reports
Journal Paper
(1). S. -H. Jeong, H. -C. Kim, T. Mizumoto, J. Wiedmann, S. Arai, M. Takenaka, and Y. Nakano, “Polarization independent all-optical switching in a nonlinear GaInAsP/InP highmesa waveguide with vertically etched Bragg reflector,” IEEE J. Quantum Electron., Vol(38), No(7), pp 706-715, Jul. 2002
　
International Conferences

(1). S.-H. Jeong, H.-C. Kim, T. Mizumoto, J. Wiedmann, S. Arai, M. Takenaka, and Y. Nakano, “Demonstration of polarization insensitive all-optical switching in a highmesa distributed feedback waveguide,” in International Technical Workshop on Contemporary Photonic Technologies (CPT 2002), Tokyo, Japan, January, 2002 (Communication Research Laboratory, Tokyo, 2002) B-5
(2). S. Arai, “InP-Based fine-structuring techniques for photonic devices,” The 14th Int’l Conf. on Indium Phosphide and Related Materials (IPRM’2002, A6-5, pp. 433-463, Stockholm, Sweden
(3). S. -H. Jeong, H. -C. Kim, T. Mizumoto, J. Wiedmann, S. Arai, M. Takenaka, and Y. Nakano, “Polarization independent all-optical switching employing nonlinear vertical groove DFB waveguide,” Optical Fiber Communication Conference (OFC 2002), Anaheim, USA, Mar., 2002, TuU3
(4). S. -H. Jeong, H. -C. Kim, T. Mizumoto, J. Wiedmann, S. Arai, M. Takenaka, and Y. Nakano, “All-optical polarization independent switching in a nonlinear DFB waveguide with vertically etched grating,” Conference on Lasers and Electro-Optics (CLEO/QELS 2002), Long Beach, USA, May, 2002, CMB2
(5). S. -H. Jeong, H. -C. Kim, T. Mizumoto, J. Wiedmann, S. Arai, M. Takenaka, and Y. Nakano, “Polarization independent switching characteristics in a passive highmesa waveguide with vertically etched Bragg reflector,” Conference on Optical Internet and Photonics in Switching (COIN+PS 2002), Cheju Island, Korea, Jul., 2002, PS.MoB5
(6). S. Arai, H.-C. Kim, and J. Wiedmann, “Functional optical devices using vertical grooved DFB and DBR structures,” SPIE International Symposium ITCom, Boston, Massachusetts, (29 July-1 August 2002) 4870-22
(7). H.-C. Kim, H. Kanjo, S. Tamura and S. Arai,: “Distributed Reflector Lasers with First-Order Vertical Gratings,” 7th OptoElectronics and Communications Conference (OECC 2002),　 Yokohama (Japan), July 8-12, 2002.
(8). H.-C. Kim, H. Kanjo, S. Tamura, and S. Arai, “Narrow stripe distributed reflector lasers with first-order vertical grating,” IEEE 18th International Semiconductor Laser Conference (ISLC), Germany, MC1, 2002
　
Meeting Reports

(1). 鄭 錫煥, 金 孝昶, 水本哲弥, ヨルク ウィドマン, 荒井滋久, 竹中 充, 中野義昭, “DFB導波路全光スイッチの偏光無依存動作特性,” 信学技報, PS 2001-87, OFT 2001-84, OPE 2001-128, LQE 2001-114, pp 55-60, 1月, 2002年
(2). H.-C. Kim, H. Kanjo, S. Tamura and S. Arai,: “1.5μm Wavelength Distributed Reflector Lasers with Deeply EtchedVertical Gratings,” 「垂直回折格子を有する1.5μm波長分布反射型レーザ」　Technical Report of IEICE, LQE2002-16 (2002-05), Fukui, May 17, 2002. 電気情報通信学会技術報告会、レーザ・量子エレクトロニクス研究会（５月）、福井、２００２年５月１７日
　
Domestic Conferences

(1). 鄭 錫煥、金 孝昶、水本哲弥、ヨルク ウィドマン、荒井滋久、竹中 充、中野義昭、“DFB導波路形偏光無依存全光スイッチ,” 電気情報通信学会総合大会、東京、2002年3月、シンポジウムセッション、SC-4-4
(2). H.-C. Kim, H. Kanjo, S. Tamura, and S. Arai,: “Distributed Reflector (DR) Laser with First Order Vertical Grating (VG),”「 一次垂直回折格子分布反射型(DR)レーザ」 The 49th Spring Meeting, 2002; The Japanese Society of Applied Physics and Related Societies, 29a-YS-11 DigestIII-pp.1145, Kanagawa, Mar. 23-29, 2002.