Hempel, M.M.HempelTomm, J.W.J.W.TommBaeumler, MartinaMartinaBaeumlerKonstanzer, HelmerHelmerKonstanzerMukherjee, J.J.MukherjeeElsässer, T.T.Elsässer2022-03-112022-03-112012https://publica.fraunhofer.de/handle/publica/37607710.1117/12.922395One of the failure mechanisms preventing diode lasers in reaching ultra high optical output powers is the catastrophic optical damage (COD). It is a sudden degradation mechanism which impairs the device functionality completely. COD is caused by a positive feedback loop of absorbing laser light and increasing temperature at a small portion of the active material, leading to a thermal runaway on a nanosecond timescale. We analyze commercial gain-guided AlGaAs/GaAs quantum well broad area diode lasers in single pulse step tests. The near-field emission on the way to and at the COD is resolved on a picosecond time scale by a streak-camera combined with a microscope. In the final phase of the step tests the COD is occurring at ~50 times threshold current. The growth of the COD defect site is monitored and defect propagation velocities between 30 and 190 m/s are determined. The final shape of the damage is verified by opening the device and taking a micro-photoluminescence m ap of the active layer.enhigh power broad area diode lasersnear-fieldfilamentationdegradationcatastrophic optical damage667conference paper