Theoretical study of linewidth enhancement factor of InGaAs/GaAs strained quantum well lasers

Abstract

A simple model of calculating the linewidth enhancement factor ( factor) is presented by introducing the correlative theory and its conversion formula of the factor in detail. The contributions of interband transition, free carrier absorption and band gap narrowing to the factor are taken into account. Carrier concentration and differential gain dependence of photon energy are obtained from the gain curves for different carrier concentrations. The gain curves and the factor of InGaAs/GaAs quantum well are simulated, separately, and the results accord well with those reported in the literature. Subsequently discussed are two important parameters of InGaAs/GaAs quantum well laser containing quantum well width and In mole fraction. The results show that the increase of two parameters leads the factor to increase.