INFLUENCE OF MIRROR REFLECTIVITY ON LASER PERFORMANCE OF VERY-LOW-THRESHOLD VERTICAL-CAVITY SURFACE-EMITTING LASERS

The influence of mirror reflectivity on laser performance of InGaAs-Ga As vertical-cavity surface-emitting lasers fabricated by selective oxi dation is investigated by the stepwise change of the number of pairs i n top mirror stack after device fabrication. Devices with 18-pair stac ks in the top mirror, which is the optimized number of pairs in this s tructure, show an output power over 1.9 mW and a slope efficiency of 5 5% while maintaining a low threshold current of 212 mu A. The analysis of the threshold current and differential efficiency related to mirro r reflectivity shows an internal quantum efficiency of 95%, an interna l round-trip loss of 0.07%, and a transparency current density of 71 A /cm(2).