21 W broad area near-diffraction-limited semiconductor amplifier

Abstract
A 600 μm wide broad area single pass GaAlAs traveling wave amplifier emitted 21 W in pulsed operation. The far-field was dominated by a near-diffraction limited 0.08° wide lobe, with 16 W measured in a 0.9° angular aperture. Current dependent scattering of the output beam power to outside of the diffraction-limited lobe was observed.