Second harmonic generation at 972 nm using a distributed Bragg reflection semiconductor laser

Abstract
We have doubled the frequency of a single mode distributed Bragg reflection (DBR) semiconductor laser. The laser is optically locked to an external enhancement ring resonator that contains an antireflection coated potassium niobate crystal. Unlike Fabry–Perot cavity lasers the DBR laser is found to operate in only one longitudinal mode and allows stable second harmonic generation. We present the results obtained with a singly and doubly resonant cavity. A total output of 1.2 mW tunable single mode radiation near 486 nm has been generated from a laser output power of 25 mW at 972 nm without the use of optical isolators or active feedback control.