Use of hybrid reflectors to achieve low thresholds in all MBE grown vertical cavity surface emitting laser diodes

Low current threshold surface emitting lasers were demonstrated with all-MBE (molecular beam epitaxy) grown vertical resonator diodes. A novel reflector structure was used on the p-side of the diode. Continuous-wave room-temperature emission at a current threshold of 40 mA was obtained in a 15- mu m device. The technology reported represents a novel approach to the problem of obtaining high reflectivity while maintaining a low series electrical resistance. The structure uses constructive interference between the reflections from a semiconductor DBR (distributed Bragg reflector) and a metal layer and is termed by a hybrid reflector. Because of the enhanced reflectivity of this combination, fewer pairs and lower index differences are required for the DBR, which allows sufficiently high electrical conductivity. This structure offers enhanced reflectivity over other structures reported in the literature and has the added benefit of simplicity in fabrication and testing.<
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