GENERALIZED BLOCH-MAXWELL FORMULATION FOR SEMICONDUCTOR-LASERS

A perturbative method, is used, which includes, for the first time, local field effects, to obtain a set of generalized Bloch equations based upon averaging of the Bloch equations over the intraband distributions by the introduction of new dynamical variables. It is shown that the new set of Bloch equations, taken in the rate-equation limit, and neglecting local field effects, leads to the standard rate equation for the carrier density. Also is shown that the index saturates because of intraband relaxation effects, whereas the pin saturates mainly due to interband transitions. In our approach, the origin of phase-amplitude coupling, manifested through the linewidth enhancement factor, lies in the asymmetric nature of the carrier distribution within the conduction and valence bands.