Strain relaxation and defect creation in diode laser bars

We discuss strains in high-power diode laser arrays, so-called cm-bars, which serve as a model device for presenting a new methodology for spectroscopic strain analysis in devices. Strain relaxation during device operation as well as the interplay between strain and defects is monitored and quantitatively analyzed. By carrying out an analysis of more than one optical transition in a quantum well device, we are able to gather information about absolute strain values and to obtain at least a partial description of the strain symmetry.