Degradation signatures of high power laser diodes

Rapid and catastrophic degradation of high power laser diodes occur because of the generation of extended defects inside the active parts of the laser structure during the laser operation. Local hot spots play a major role as actuators of the driven force leading to the formation of extended crystal defects. The laser power threshold for degradation is very sensitive to the packaging induced stress, and the thermal conductivity of the multilayer structure. The thermal conductivity of the QW and the barriers is suppressed by the low dimensionality but also by the quality of the interfaces being a major actor of the laser diode degradation. Modelling the thermal stresses induced by the hot spots in the active region of the diode permits to describe the degradation mechanisms of high power laser diodes.