Steady-state, dynamic and spectral performance of microcavity surface-emitting strained quantum-well lasers

摘要

We examine the modifications in the spontaneous emission pattern of a microscopic cavity semiconductor laser in the surface-emitting geometry and their influence on the laser characteristics. We find that the threshold current density can be reduced to 60 A/cm~2 for a laser embedded in a cavity with a transverse dimension of 0.5 μm, while the -3dB modulation frequency exceeds 20 GHz for a moderate injected current density of 600 A/cm~2, allowing high-speed operation without laser heating that normally accompanies high current injections. Linewidths of several hundred MHz at moderate power levels are calculated for microcavity lasers resulting from a balance of the enhancement of the fraction of spontaneous emission coupling into the lasing mode and of the reduction of the linewidth enhancement factor in the strained active region.