Abstract

Semiconductor lasers have been treated theoretically in the past by adopting a phenomenological approach that assumes that gain and refractive index changes vary linearly with the injected carrier density N and by introducing three ad hoc parameters to describe the material gain and refractive index changes. However, earlier bifurcation studies of the coupled mode model for multi-stripe index guided laser arrays show that the instability thresholds and consequent dynamic behavior will be a sensitive function of these three parameters. This important issue can be best resolved by appealing to a fundamental many-body theory of the interaction of light with semiconductor media. An obvious advantage of such a theory is that one can dispense entirely with ad hoc parametrization and compute the material parameters directly from first principles. We will report on a study that compares a phenomenological model extended to include transverse and longitudal effects, with parameters obtained from fitting gain and refractive index functions obtained from microscopic many-body theory and a full scale space-time evolution using a look-up table of these functions. The phenomenological approach is found to fail for weakly index guided or pure gain guided coupled laser structures.

© 1992 Optical Society of America