High-Power AlGaInN Lasers for Blu-ray Disc system

摘要

This paper describes an improved laser structure for AlGalnN based blue-violet lasers (BV-LDs). The design realizes a small beam divergence angle perpendicular to the junction plane and high characteristic temperature without significant increase in threshold current density (J_(th)) by optimizing the position of the Mg-doped layer and introducing an undoped AlGaN layer between the active layer and the Mg-doped electron-blocking layer. The mean time to failure (MTTF) of devices based on this design was found to be closely related to the dislocation density of ELO-GaN basal layer. Under 50 mW CW operation at 70 °C, a MTTF of over 5000 h was realized when the dark spot density (indicative of dislocation density) is less than ～5 x 10~6 cm~(-2). Power consumption under 50 mW CW operation at 70°C was approximately 0.33 W, independent of the dislocation density.