| Project/Area Number |
62850065
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| Research Category |
Grant-in-Aid for Developmental Scientific Research
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| Allocation Type | Single-year Grants |
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| Research Field |
電子機器工学
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| Research Institution | University of Tokyo |
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Principal Investigator |
TADA Kunio Faculty of Engineering, University of Tokyo,Professor, 工学部, 教授 (00010710)
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| Co-Investigator(Kenkyū-buntansha) |
MOTOSUGI Tsuneharu NTT Optoelectronics Laboratory,Seni, 光エレクトロニクス研究所, 主幹研究員
MURAI Toru Faculty of Engineering, University of Tokyo,Research Ass, 工学部, 助手 (60107571)
NAKANO Yoshiaki Faculty of Engineering, University of Tokyo,Lecture, 工学部, 講師 (50183885)
IKOMA Toshiaki Institute of Industrial Science, University of Tokyo,Professor, 生産技術研究所, 教授 (80013118)
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| Project Period (FY) |
1987 – 1988
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| Project Status |
Completed (Fiscal Year 1988)
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| Budget Amount *help |
¥11,900,000 (Direct Cost: ¥11,900,000)
Fiscal Year 1988: ¥3,700,000 (Direct Cost: ¥3,700,000)
Fiscal Year 1987: ¥8,200,000 (Direct Cost: ¥8,200,000)
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| Keywords | distributed feedback(DFB) semiconductor laser / short wavelength region / modulated stripe width structure / longitudinal spatial hole burning / reactive ion etching / visible light / gain coupling / 一体集積化 / 反応性イオンエッチング |
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| Research Abstract |
1.DFB Laser with Modulated Stripe Width structure We applied the modulated stripe width structure to short wavelength region distributed feedback (DFB) lasers for achieving complete single longitudinal mode oscillation in them. This structure was made possible by employing a novel reactive ion etching (RIE) technigue for composite xemiconductors. At the same time several new techniques were introduced for the fabrication of diffraction grationgs, including the use of RIE for transferring the grating patterns onto the epitaxial layers. AS a result the tooth shape of the grating was greatly improved. To our knowledge the device thus fabricated was the first buried heterostructure DFB laser completed without wet etching. Next we developed an accurate device simulator in order to investigate the exact effect of longitudinal spatial hole burning on the characteristics of this kind of phase-shifted DFB laser. From the calculated results we designed appropriate stripe shapes for reducing the
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wavelength chirping as a consequence of minimizing that effect.
2. Visible Light DFB Laser On our experience of having developed high performance 0.88 m DFB lasers, we next tried further reduction of oscillation wavelength. By modifying and improving the fabrication processes, we succeeded in obtaining DFB oscillation in visible wavelength region(【.Ibdabar.】=770nm) in our simple oxide stripe devices. Temperature dependence of oscillation wavelength was 0.054nm/K, and mode hopping was not observed within temperature range over 50K.
3. DFB Laser with Gain Coupling Mechanism We for the first time introduced the gain coupling mechanism to the semiconductor DFB laser, and showed its usefulness for complete single longitudinal mode oscillation. We also found out that the lasing characteristics of a DFB laser of this kind are almost immune to facet reflection, which made a striking contrast with the conventional DFB lasers. This feature is the one that has been eagerly demanded but never realized.
4. DFB Laser monolithically integrated with Optical Modulator/Amplifier Monolithic integration of a 0.88 m DFB laser and an optical modulator/amplifier was examined. Since, in integrated devices of this sort, optical isolation between element devices is essentially important, we first estimated the maxinum tolerable reflectivity at the front facet by carrying out numerical analysis of the osdillation and modulation characteristics. Fabrication of a prototype device has been completed. Less
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