Analysis of heat flows and their impact on the reliability of high-power diode lasers

Facet overheating is considered a potential source for device degradation of diode lasers. We test two different concepts for the reduction of facet temperatures of high-power diode lasers by measuring the facet temperatures by means of Raman spectroscopy. For conventional high-power broad area lasers we demonstrate the reduction of the facet overheating by the introduction of current blocking layers by a factor of 3-4. For another set of devices among them quantum well and quantum-dot lasers with almost the same device design we find a reduction of the overheating by 40 to 60 percent for the dot devices. Thus we qualify two very different but promising technological approaches for increasing device reliability.