Simultaneous quantification of strain and defects in high-power diode laser devices

Photocurrent spectroscopy is applied for an analysis of both packaging-induced strain and strain-induced defect creation in InAlGaAs/GaAs high-power diode laser arrays. Strain profiles across 50 W diode lasers processed by different packaging procedures are measured and compared to model calculations. We demonstrate that packaging-induced strain giving rise to spectral shifts of the laser transition correlates with packaging-induced defects in the waveguide that are quantified via a sub-band gap absorption band. Packaging on a Cu–diamond multilayer heat spreader appears as optimized solution simultaneously minimizing strain and defect creation.