Bonding induced stress in semiconductor laser

The TM mode in a semiconductor laser is often associated with tensile stress and therefore the laser fabrication processes are optimized so that the active waveguide layer is in compression. Our experiments suggest that hard solder such as AuSn induces compressive stress in the laser chip which is dependent on the process and the submount material. Using a thermal expansion model we have calculated the stress in the laser chip for various submount materials