Spectroscopy of mounting-induced strain and strain-induced defects in InAlGaAs/GaAs high-power diode lasers

Mounting of high-power diode laser array chips and bars without impairing their initial properties appears as a challenging task for optimization work. On the one hand only a very tight physical contact between laser chip and heat sink secures low thermal resistances. On the other hand such soldering processes might introduce strain and defects into the laser devices and rather smooth technologies based on In-solders appear advantageous. This optimization work must be done by technologists, however, an analytical tool is urgently required, that provides information on strain as well as about defects, that are introduced by the packaging process. We demonstrate that photocurrent spectroscopy is exactly the tool that meets both these demands