Gain and saturation in semiconductor lasers

Several approaches have been developed for modelling the gain and saturation behaviour of semiconductor lasers, and this study includes a historical review of these various approaches. Special attention is given to rate equation models and to the possibility of so-called gain nonlinearities that might affect the CW and modulation performance of semiconductor lasers. Discussions are mainly limited to the GaAs/GaAIAs and InGaAsP/InP systems, for which the gain and gain nonlinearities have been most extensively studied.