Highly-efficient operation and mode control in GaN-based VCSELs with a curved mirror

Abstract

We report the latest progress of gallium nitride-based Vertical-Cavity Surface-Emitting Lasers (VCSELs) containing a curved mirror. Highly uniform and efficient devices were developed. The average threshold current was 0.64 mA with a standard deviation of 0.043 mA. The peak wall-plug efficiency and output power were 13.4 % and 7.6 mW at operating currents of 5.2 mA and 12.8 mA, respectively. We obtained green VCSELs with milliwatt-class outputs and a wall-plug efficiency of 3.7%. We also report the progress of VCSELs with a single-cavity filtering mirror and a cavity length of approximately 25 μm showing highly varying reflectivity spectra, to demonstrate their single-longitudinal mode operation.