Bandwidth enhancement of Fabry-Perot quantum-well lasers by injection-locking

• Published in: Solid-state electronics Vol. 50; no. 6; pp. 1141 - 1149
• Main Authors: Jin, Xiaomin, Chuang, Shun-Lien
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Oxford Elsevier Ltd 01.06.2006; Elsevier Science
• Subjects: Applied sciences; Circuit properties; Compound structure devices; Electric, optical and optoelectronic circuits; Electronics; Exact sciences and technology; Fundamental areas of phenomenology (including applications); Injection locking; Integrated optics. Optical fibers and wave guides; Lasers; Modulation bandwidth; Optical and optoelectronic circuits; Optical injection; Optics; Physics; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Semiconductor laser; Semiconductor lasers; laser diodes; Optical injection; Modulation bandwidth; Injection locking; Semiconductor laser; Multimode laser; Confinement; Gallium arsenides; Small signal behavior; Indium phosphide; Transport process; Relaxation; Direct current; Optical characteristic; Quantum well lasers; Fabry Perot resonator; Electrical characteristic; Electrical signal; Quantum well; Mode locking; Multiple quantum well; Enhancement factor; Gallium phosphide; Injection laser; Indium arsenides; Quaternary compound; Line width; Optical frequency conversion; Gain
• ISSN: 0038-1101; 1879-2405
• DOI: 10.1016/j.sse.2006.04.009

Theory and experiment for dc and small-signal electrical modulation of an injection-locked quantum-well (QW) Fabry-Perot laser are presented. Our experiment is realized by performing side-mode injection locking of a multiple-quantum-well (MQW) InGaAsP Fabry-Perot (FP) laser, which has the advantage of optical wavelength conversion. We first measure the dc characteristics and optical spectra of an injection-locked laser to define its locking range and linewidth enhancement factor. We then show experimentally that the bandwidth of an injection-locked semiconductor laser is 10.5 GHz, which is around twice the free-running electrical modulation bandwidth (5.3 GHz). The relaxation frequency of the injection-locked laser can be 3.5 times greater than the free-running value. Our theoretical model includes mode competition, gain saturation, low frequency roll-off, and optical confinement factor of the QW structure. The theory shows good agreement with our experimental results. We point out that the small-signal modulation of injection-locked lasers still suffers severely from low frequency roll-off, which comes from the carrier transport effect and parasitic effect of the bias circuit. If we can reduce those effects, the modulation bandwidth can be further increased to 15 GHz, which is around 3 times of the free-running value.