Gradual degradation of red-emitting high-power diode laser bars

The authors analyze early stages of gradual degradation in highly reliable 650 nm emitting high-power diode laser arrays with continuous wave emission powers of 2.5 W (facet load of 4 mW/mu m). In all cases the edges of the metallized emitter stripes are identified as the starting points of gradual degradation. The magnitude of the observed degradation signatures, however, is highly correlated with the bar-specific packaging-induced strain at each emitter. We find a bar-specific effect, namely, the presence of packaging-induced strain, to be the driving force of gradual degradation. Our findings point to the significance of proper strain management in advanced device structures. (c) 2007 American Institute of Physics.