A monolithically integrated InGaAs-AlGaAs master oscillator power amplifier with grating outcoupler

Semiconductor monolithically integrated master oscillator power amplifiers on compound semiconductor substrates are expected to be widely used as comp act high-power light sources. This paper reports a high-power semiconductor laser consisting of a curved surface DBR grating, a tapered power amplifie r, and a grating outcoupler, which can be fabricated by a simple process wi thout regrowth and which emits a collimated output beam. The power amplifie r is designed according to theoretical simulation by the beam propagation m ethod and the grating outcoupler is designed to compensate the wavefront di stortion produced in the amplifier. The integrated device was fabricated an d evaluated. A collimated output beam with a wavelength of 985 nm and a max imum output power of 124 mW was obtained in CW operation. Reduction of the degradation in output collimation due to wavefront distortion was confirmed , even in the high injection current region of the amplifier, owing to the use of the compensation function of the outcoupler. (C) 2001 Scripta Techni ca, Electron Comm Jpn Pt 2, 84(3): 61-70, 2001.