Optical Gain and Optical Internal Loss of GaN-Based Laser Diodes Measured by Variable Stripe Length Method with Laser Processing : Optics and Quantum Electronics

We demonstrate a new technique for the variable stripe length (VSL) method by which the optical gain and optical internal loss of GaN-based laser diodes (LDs) can be directly measured. In the technique, the laser processing is utilized for varying the excitation length. The excitation length of GaN-based LDs can be varied by directly processing its p-electrode with high-power laser irradiation. From the results of the measurements, it was revealed that the optical internal loss of GaN-based LDs was strongly affected by the layer structure.