Measurement systems for the investigation of soldering quality in high-power diode laser bars

Thermal and spatial-spectral imaging methods are used to investigate the soldering quality in high-power laser-bar devices. The temperature distribution and the wavelength profile across a driven laser bar correlate with the local thermal resistance between laser and cooler and, thus, with the uniformity of the solder layers. Measurements with a properly soldered and a deficiently soldered laser bar are made for the illustration and comparison of the methods.