| Co-Investigator(Kenkyū-buntansha) |
バーツ ルル ゲント大学, 情報工学研究所, 助教授
LUO Yi Tsinghua Univ., Dept.of Electronic Eng., Professor, 電子工程系, 教授
スミット マイントK. デルフト工科大学, 電気工学科, 教授
コルドレン ラリーA. カリフォルニア大学, サンタバーバラ校, 教授
TADA Kunio Univ.of Tokyo, School of Engineering, Professor, 工学系研究科, 教授 (00010710)
SMIT Meint K. Delft Univ.of Technology, Dept.of Electrical Eng., Professor
COLDREN Larry A. Univ.of California, Santa Barbara, Professor
BAETS Roel Univ.of Gent, Dept.of Information Tech., Associate Professor
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| Research Abstract |
1.Extraction of gain-coupling coefficient
We established a new parameter extraction method where theoretical spectra were numerically fitted onto experimetal amplified spontaneous emission spectra below lasing threshold, and made measurement of gain coupling coefficients possible for the first time. Using this technique, we experimentally verified the theoretical prediction that the coupling coefficients in gain-coupled distributed feedback (GC DFB) lasers of absorptive grating type change with injection current.
2.Small signal direct modulation characteristics
We measured small signal modulation response in GC DFB lasers and extracted relaxation oscillation frequency and damping factor. As a result, unlike the conventional lasers, their damping factor had a region where it decreased with increasing optical output power. By making use of this phenomenon, we will be able to extend the modulation bandwidth beyond that of common DFB lasers.
3.Analysis and measurement of analog modulation distortion
We analyzed analog modulation distortion in GC DFB lasers of absorptive grating type by a newly-developed numerical method. As a result, the second harmonic distortion was found to be reduced due to cancellation of gain compression in the active layr by absorption compression in the grating. A preliminary experiment was conducted to confirm the above theoretical prediction.
4.Fabrication of GC DFB laser triode
1.55mum wavelength band GC DFB laser triodes have successfully been fabricated for the first time by four step metal organic vapor phase epitaxy (MOVPE).
5.Fabrication of a GC DFB laser with quantum wire active region
By making use of MOVPE growth on V-grooved substrates, a GC DFB laser with InGaAs strained quantum wire active region has successfully been fabricated for the first time.
6.Fabrication of MMI couplers by selective-area MOVPE
We successfully fabricated multimode interference (MMI) couplers by selective-area MOVPE for the first time.
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