Packaging-Induced Strain Measurement Based on the Degree of Polarization in GaAsP–GaInP High-Power Diode Laser Bars

The strain caused by device packaging was studied in high-power semiconductor laser bars by measuring the degree of polarization. Polarization measurement with intentionally GaAsP-GaInP strained laser bar packaged on a Cu heat sink for 799-nm emission revealed the variation of band edges between the conduction band and heavy-hole or light-hole bands in the active region. This served as a method for evaluating the strain. In the packaging process, a maximum of 1800-ppm strain was transmitted to the active region. It was found that the defect density of 14.3% was induced.