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The influence of the quantum well (QW) interfaces with the barrier layers on the rapid degradation of AlGaAs based high power laser bars (808 nm) is investigated. Thermal stresses induced in the device by the local heating produced by nonradiative recombination areas at the facet mirror are calculated by means of a thermomechanical model. Results show that the laser power density threshold necessary to achieve the plastic deformation, leading to the generation of dislocations and to the failure of these devices, is reduced as the quality of the QW interfaces worsens in terms of thermal boundary resistance.

A thermomechanical model for the mechanism of rapid degradation of AlGaAs based high power laser bars (808 nm) is presented. Thermal stresses induced in the device by local heating around a facet defect by nonradiative recombination and self-absorption of photons are calculated, as well as the conditions for the beginning of plastic deformation, when these thermal stresses overcome the yield strength. The values of the power density and of the local temperature at which the yield limit is surmounted are in agreement with the threshold values for the degradation of Al based lasers given in the literature. The present model can also elucidate the role played by the packaging stress, being able to explain how this stress reduces the optical power density threshold for failure of these lasers.