Influence of geometrical factors on angled broad-area semiconductor lasers for high-output power with good beam quality

Abstract

High-power semiconductor lasers with good beam quality are important for many applications. Angled broad-area waveguide structure could increase the output power and the beam quality is maintained at good quality. In this paper, we report the in-depth investigation on the geometrical factors that influence the performance of angled broad-area semiconductor lasers. The angled broad-area laser diodes are based on InGaAsP/InP materials. The waveguide is oriented at an angle from the normal of the cleaved facets. Our investigation shows that the waveguide width, the device length, and the tilted angle have to follow a certain relation in order to have the light propagate along a zigzag path inside the broad-area waveguide. When such a mode oscillates, the output light emits along the normal of the cleaved facet, showing no filamentation. Over 1 W of output power can be obtained with a good beam quality. Our investigation also discovers that devices with 100μm waveguide width perform better than devices with 50μm waveguide width.