LD11–Influence of Coulomb Scattering on the Coupling between Longitudinal Modes in Nitride Laser Diodes

Due to their small separation of longitudinal modes, Fabry-Perot type laser diodes show rich mode competition effects. For example streak camera measurements show cyclic mode hopping, where the currently active longitudinal mode changes from lower to higher wavelengths. This effect can be explained by beating vibrations of the carrier densities in the quantum wells and can be included in rate equation simulations by using an effective mode coupling term. In this work we calculate this effective mode coupling term on a microscopic level using Coulomb scattering. We investigate how the effective coupling term depends on the carrier densities in the quantum wells for a green nitride laser diode and compare the result with coupling terms found in literature. The behavior is similar if the frequency difference of the longitudinal modes is small, deviations are observed for larger frequency differences.