DocumentCode :
1397437
Title :
Threshold current, differential gain, and relaxation resonance frequency of 1.55-μm bulk and MQW DFB laser diodes
Author :
Kakimoto, Syouichi ; Watanabe, Hitoshi
Author_Institution :
Optoelectron. & Microwave Devices R&D Lab., Mitsubishi Electr. Corp., Hyogo, Japan
Volume :
34
Issue :
7
fYear :
1998
fDate :
7/1/1998 12:00:00 AM
Firstpage :
1231
Lastpage :
1239
Abstract :
We investigate threshold currents, differential gains, and relaxation resonance frequencies of 1.55-μm bulk and nine-well multiple-quantum-well (MQW) distributed feedback (DFB) laser diodes (LDs) experimentally and theoretically. The experimentally obtained threshold current (Ith), differential gain (dg/dN), and relaxation resonance frequency per square root of output power (fr/(P) 1/2) of the 1.55-μm bulk DFB LD are 19 mA, 2.4×10 -16 cm2, and 3.2 GHz/mW1/2, which nearly agree with the calculated Ith of 21.6 mA, dg/dN of 3.1×10-16 cm2, and fr/(P)1/2 of 3.6 GHz/mW1/2, respectively. The experimentally obtained I th, dg/dN, and fr/(P)1/2 of the 1.55-μm InGaAs MQW DFB LD with barriers (λg=1.3 μm) are 9 mA, 6.0×10 -16 cm2, and 4.6 GHz/mW1/2 compared with the calculated Ith of 7.8 mA, dg/dN of 4.0×10-16 cm2, and fr/(P)1/2 of 3.7 GHz/mW1/2, respectively. However, the experimentally obtained Ith, dg/dN, and fr/(P)1/2 of the 1.55-μm InGaAs MQW DFB LD with barriers (λg=1.15 μm) are 20 mA, 2.6×10-16 cm2, and 2.85 GHz/mW1/2 , which greatly disagree with the calculated Ith, of 4.9 mA, dg/dN of 6.0×10-16 cm2, and fr/(P) 1/2 of 4.3 GHz/mW1/2, respectively. Taking into account the nonuniform hole distribution among nine wells, which is attributed to the valence band discontinuity, ΔEυ (the separation between the first quantized hole level in the well and the top energy of the valence band for the barrier), the corrected Ith and dg/dN of the 1.55-μm MQW DFB LD with λg of 1.15 μm are 18.3 mA and 2.2×10-16 cm2, which fairly agree with the above measured values. By p-type doping to 1.5×1018 cm-3 into the wells to improve the nonuniform distribution of holes among nine wells, Ith, dg/dN, and fr/(P)1/2 of the 1.55-μm MQW DFB LD with λg of 1.15 μm can be expected to be 3.7 mA, 8.8×10-16 cm2, and 5.4 GHz/mW1/2, respectively
Keywords :
distributed feedback lasers; infrared sources; laser transitions; light sources; quantum well lasers; relaxation; semiconductor doping; valence bands; 1.55 mum; 18.3 mA; 19 mA; 3.7 mA; 7.8 mA; InGaAs MQW DFB LD; MQW DFB laser diodes; bulk DFB LD; differential gain; first quantized hole level; nine-well MQW DFB laser diodes; nonuniform hole distribution; output power; p-type doping; relaxation resonance frequency; threshold current; valence band; Diode lasers; Distributed feedback devices; Doping; Energy measurement; Indium gallium arsenide; Power generation; Quantum well devices; Resonance; Resonant frequency; Threshold current;
fLanguage :
English
Journal_Title :
Quantum Electronics, IEEE Journal of
Publisher :
ieee
ISSN :
0018-9197
Type :
jour
DOI :
10.1109/3.687867
Filename :
687867
Link To Document :
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