Experimental observation of chirp reduction in bandwidth-enhanced semiconductor lasers subject to strong optical injection

An optically injection-locked semiconductor laser under direct current modulation is experimentally studied. Significant increase in the relaxation resonance frequency is first demonstrated, implying the same degree of enhancement in modulation bandwidth. Under bandwidth-enhanced operating conditions, substantial reduction in frequency chirping is observed, which demonstrates that significant bandwidth enhancement and chirp reduction are simultaneously achieved in experiment. Chirp reduction as a function of modulation frequency is also investigated. Substantial chirp reduction happens at low modulation frequency. However, the frequency chirping reduces less with increasing modulation frequency. The frequency chirping of the injection-locked laser approaches to that of the free-running laser at high modulation frequency. Effective chirping parameter is introduced and analyzed for the injection-locked laser to study the physical mechanism behind the chirp reduction.

[1]  Hongwei Chen,et al.  Response characteristics of direct current modulation on a bandwidth-enhanced semiconductor laser under strong injection locking , 2000 .

[2]  T. B. Simpson,et al.  Four-wave mixing and optical modulation in a semiconductor laser , 1994 .

[3]  Sheng-Kwang Hwang,et al.  Dynamical characteristics of an optically injected semiconductor laser , 2000 .

[4]  Paolo Spano,et al.  Small signal analysis of frequency chirping in injection-locked semiconductor lasers , 1986 .

[5]  H.F. Chen,et al.  Modulation bandwidth, noise, and stability of a semiconductor laser subject to strong injection locking , 1997, IEEE Photonics Technology Letters.

[6]  N. A. Olsson,et al.  Chirp-free transmission over 82.5 km of single mode fibers at 2 Gbit/s with injection locked DFB semiconductor lasers , 1985 .

[7]  Yoh Ogawa,et al.  Enhanced modulation bandwidth for strain-compensated InGaAlAs-InGaAsP MQW lasers , 1998 .

[8]  C. Lin,et al.  Reduction of frequency chirping and dynamic linewidth in high-speed directly modulated semiconductor lasers by injection locking , 1984 .

[9]  Ming C. Wu,et al.  Experimental demonstration of modulation bandwidth enhancement in distributed feedback lasers with external light injection , 1998 .

[10]  G. D. Boyd,et al.  Reduced dynamic linewidth in three-terminal two-section diode lasers , 1985 .

[11]  J.M. Liu,et al.  Enhanced modulation bandwidth in injection-locked semiconductor lasers , 1997, IEEE Photonics Technology Letters.

[12]  J. Cartledge.  Improved transmission performance resulting from the reduced chirp of a semiconductor laser coupled to an external high-Q resonator , 1990 .

[13]  P. Tasker,et al.  Control of differential gain, nonlinear gain and damping factor for high-speed application of GaAs-based MQW lasers , 1993 .

[14]  Klaus Petermann.  Analysis of reduced chirping of semiconductor lasers for improved single-mode-fibre transmission capacity , 1985 .

[15]  G. Yabre.  Effect of relatively strong light injection on the chirp-to-power ratio and the 3 dB bandwidth of directly modulated semiconductor lasers , 1996 .

[16]  Philippe Gallion,et al.  Contribution of spontaneous emission to the linewidth of an injection-locked semiconductor laser , 1985 .