Role of Thermal Stresses in Degradation of High Power Laser Diodes

Catastrophic degradation of high power laser diodes is due to the generation of extended defects inside the active parts of the laser structure during the laser operation. The mechanism driving the degradation is strongly re- lated to the existence of localized thermal stresses generated during the laser operation. These thermal stresses can overcome the yield strength of the materials forming the active part of the laser diode. Different factors contribute to reduce the laser power threshold for degradation. Among them the thermal transport across the laser structure constitutes a critical issue for the reliability of the device.