Spontaneous emission and gain in GaAlAs quantum well lasers

Measurements of spontaneous emission from GaAlAs single quantum well lasers over a wide range of carrier densities are discussed. From these measurements, the optical gain, refractive index, and linewidth enhancement factor are determined, all of which contribute to the overall performance of a semiconductor laser. In addition, a simple model which adequately describes the important features in the spontaneous emission (and therefore the gain) data is presented. With this model, quantitative information about the carrier density-dependent bandgap shrinkage, lifetime broadening, and the shape of the broadening functions is obtained.>