Catastrophic Optical Damage of GaN-Based Diode Lasers: Sequence of Events, Damage Pattern, and Comparison with GaAs-Based Devices

Gallium-nitride-based diode lasers were intentionally damaged using single sub-μs current pulses. This approach provoked catastrophic optical damage, a known sudden degradation mechanism, which becomes evident as surface modification at the aperture, where the 450-nm laser emission leaves the waveguide of the device. Subsequently, we analyzed the related damage pattern inside the device. Knowledge about the operating conditions, degradation time, and energy introduced into the defect allows estimates of the temperature during the process (∼ 1000°C) and defect propagation velocity (110 μm/μs). Further analysis of this data allows for conclusions regarding the mechanisms that govern defect creation at the surface and defect propagation inside the device. Moreover, we compared these findings with earlier results obtained from gallium-arsenide-based devices and find similarities in the overall scenario, while the defect initialization and defect pattern are strikingly different.