Modeling of facet heating in high-power laser diodes

Facet heating is an important mechanism limiting the performance of high power laser diodes. The temperature increase at the laser facets contributes to the gradual degradation and can lead to Catastrophical Optical Damage (COD). We present a two-dimensional optoelectronic and thermal model for Fabry-Perot Quantum Well power lasers. The model is applied to 808 nm AlGaAs laser bars, with the aim of identifying the main volume and facet heating sources. The results of the simulation show that the heating caused by free-carrier absorption is the main source that could be minimized by a proper layer design. We present a new physical mechanism leading to COD: optical absorption at the facets produces carrier accumulation that can trigger the thermal runaway process.