A physical model for the rapid degradation of semiconductor laser diodes

The degradation of AlGaAs based high power laser bars (808 nm) is modeled in terms of the thermal stress gradient induced by the overheating produced at a facet defect by self-absorption and nonradiative recombination. Using a thermomechanical model, the local heating at the defect is shown to induce local stress above the yield strength necessary for plastic deformation. Cathodoluminescence images of the facets show the formation of large facet defects. The role of the packaging stress is also elucidated. The power density dissipation and the local temperature necessary to achieve the plastic deformation are in good agreement with the experimental values reported for laser degradation. (C) 2008 American Institute of Physics. {[}DOI: 10.1063/1.3009290]