Waveguide Width Dependence of Reliability in GaAs-Based Laser Diodes

High output power and reliability are prerequisites for laser diode (LD) applications. While broad-area LDs (e.g., waveguide width wider than ∼ 50 μm) are preferred for high-power applications, narrow-waveguide LDs (e.g., waveguide width of ∼ 5 μm) are demanded due to their single-mode characteristics. Although their reliability is mainly limited by catastrophic optical damage (COD), the dominant failure mechanisms depend on the waveguide width. Broad-area LDs commonly demonstrate mirror damage (COMD), whereas narrow-waveguide LDs are usually COMD-free. In this work, we compare the laser and facet temperatures in conjunction with the thermal simulation of the LDs for various waveguide widths to investigate the underlying mechanism.