In situ characterization of strain distribution in broad-area high-power lasers under operation by high-resolution x-ray diffraction and topography using synchrotron radiation

The strain distribution in broad-area high-power semiconductor laser diodes is investigated both before and during operation and degradation by high-r esolution x-ray diffraction using synchrotron radiation. An inhomogeneous s train distribution along the stripe and at the stripe edges is found due to the mounting and bonding of the laser device. From the current-induced the rmal lattice expansion the temperature rise during operation near the activ e region is estimated. The radius of curvature of the laser changes during operation and a different thermal behaviour on the front and the rear facet is found. The temperature distribution along the laser stripe could be cor related with the defect distribution observed after degradation by cathodol uminescence.