MONOLITHICALLY INTEGRATED INGAAS-ALGAAS MASTER OSCILLATOR POWER-AMPLIFIER WITH GRATING OUTCOUPLER

A monolithically integrated master oscillator power amplifier with a g rating outcoupler, fabricated using a simple process without regrowth and emitting a collimated output beam, is proposed and demonstrated us ing an InGaAs-AlGaAs strained single-quantum-well gradient-index separ ate-confinement-heterostructure. Stable single-mode lasing up to 124-m W output power was obtained under continuous-wave operation. An increa se of the output beam divergence, due to a wavefront distortion produc ed in the power amplifier, was observed with increasing power amplifie r injection current. The wavefront distortion can be compensated by an appropriate design of the grating outcoupler.