High-Power Single-Spatial-Mode GaSb Tapered Laser around 2.0μm with Very Small Lateral Beam Divergence

We report high-power single-spatial-mode type-I GaSb-based tapered lasers fabricated on the InGaSb/AlGaAsSb material system. A straight ridge and three different tapered waveguide structures with varying flare angles are fabricated to optimize the output power and spatial-mode performance. The best devices exhibit single-spatial-mode operation with room-temperature output power up to 350 mW in continuous-wave mode at an emission wavelength around 2.0 μm with a very small far-field lateral divergence angle, which is beyond state of the art in terms of single-spatial-mode output power.