Self-consistent analysis of quantum well number effects on the performance of 2.3- μm GaSb-based quantum well laser diodes

We self-consistently analyze the effect of quantum well (QW) number on the performance of semiconductor lasers based on GaSb material emitting at 2.3 μm. The analysis is performed with commercial software that combines gain calculation with 2-D simulations of carrier transport and wave guiding. The laser model implemented in the software was calibrated using experimental results. Excellent agreement between simulation and experimental results was achieved. The calibrated model was then used to simulate the performance of these lasers as a function of the number of QWs. The analysis includes the cavity length dependence of the threshold current density, the characteristic temperature, and the emitted optical power reduction at a constant current with increasing temperature. Our simulation shows that the transparency current density and the gain parameter increase with a rate of ∼16 A/cm² and 6.82 cm ^-1 per QW, respectively. The internal loss is mainly due to free carrier in the p-type layers. The simulation shows that the optimum number of QWs for the characteristic temperature, threshold current, and optical power reduction depends strongly on the cavity length.