Abstract

Intraband gain saturation is a nonlinear phenomenon occurring in semiconductor lasers when the intracavity intensity is high enough to significantly modify the intraband occupation probabilities of charged carriers. The nonperturbative solution of the single-mode density-matrix equations is used to obtain the intensity-dependent changes in the gain and the refractive index of the optical mode. The effect of such gain and index nonlinearities is studied by solving a set of modified rate equations that incorporate gain saturation due to both the interband and the intraband processes. The results show how the modulation response and the noise characteristics such as the laser linewidth are affected by a finite intraband relaxation time in semiconductor lasers.

© 1991 Optical Society of America