Dependence of nonlinear gain effect on threshold gain in semiconductor lasers  An optimization for highspeed modulation
Abstract
The dependence of nonlinear gain parameter and K factor on material gain in semiconductor lasers has been investigated theoretically by calculating (dg/dS)(S = 0) derivative of gain g with respect to photon density S. If spectral hole burning is assumed, the square of the lineshape function appears in dg/dS. This implies that the contributions from highenergy electronhole pairs are reduced, and that (dg/dS)(S = 0) takes a finite negative value at transparent point (g = 0). The nonlinear gain parameter, therefore, diverges as the gain approaches zero. The K factor is minimized at a value of material gain, which is estimated to be 4.3/ps for typical InGaAs/InGaAsP quantum well lasers. The confinement factor should be designed to maintain the gain at the optimum value.
 Publication:

IEEE Photonics Technology Letters
 Pub Date:
 April 1992
 DOI:
 10.1109/68.127207
 Bibcode:
 1992IPTL....4..342T
 Keywords:

 ElectronHole Drops;
 Gallium Arsenide Lasers;
 Nonlinear Optics;
 Power Gain;
 Indium Gallium Arsenides;
 Indium Phosphides;
 Optimization;
 Quantum Wells;
 Velocity Modulation;
 Lasers and Masers