Recent progress of high-power InGaN blue-violet laser diodes

We report on the development of GaN-based violet laser diodes (LDs) for the high-capacity optical storage application and blue LDs for the laser projection display application. InGaN LDs with emission wavelength of ∼405 nm are already being adopted for next-generation optical-storage systems. We present results on >400 mW single-mode output power under pulsed operation which can be employed in 100 Gbyte multi-layer BD systems. We designed LD layer structures to exhibit high level of catastrophic optical damage (COD) and small beam divergence. In addition, GaN-based blue LDs with emission wavelength of ∼450 nm have also been developed for the application to the blue light sources of laser display systems. We demonstrate single-mode blue InGaN LDs with >100 mW CW output power. Interestingly, we observed anomalous temperature characteristics from the blue InGaN LDs, which has shown highly-stable temperature dependence of output power or even negative characteristic temperature (T₀) in a certain operation temperature range. This unusual temperature characteristic is attributed to originate from unique carrier transport properties of InGaN QWs with high In composition, which is deduced from the simulation of carrier density and optical gain.