The laser diodes (LD) have numerous applications and promise to become key elements for next generation laser
technologies. LD are usually operated under conditions of heavy thermal load. As a result, the devices are affected by
aging processes leading to changes of the operation parameters, degradation and, eventually, complete failure.
Degradation of high power semiconductor lasers remains a serious problem for practical application of these devices. We
investigated the effect of mounting induced strain and defects on the performance of high power laser. In this paper
measurements of the temperature distribution and the electroluminescence along the cavity of InGaAs quantum well
lasers before and after accelerated aging processes are presented. The electro-optical parameters of the high output power
laser diodes, such as emission wavelength, output power, threshold current, slope efficiency, and operating lifetime are