Spectral holehyphen;burning and gain saturation in semiconductor lasers: Stronghyphen;signal theory

摘要

The nonlinear susceptibility of semiconductor gain media is obtained by including the effect of intraband carrier relaxation within the densityhyphen;matrix formalism. The result is used to obtain the approximate analytic expressions showing how the optical gain and the refractive index change with an increase in the laser power. The index change is generally small but can be positive or negative depending on which side of the gain peak the lasing mode is located. By contrast, the gain is always reduced because of spectral holehyphen;burning. The implications of gain saturation on the dynamic response of semiconductor lasers are discussed together with the possibility of experimental verification.