High-power 1.9-µm diode laser arrays with reduced far field angle

High-power 1.91-µm (AlGaIn)(AsSb) quantum-well diode laser single emitters and linear arrays with improved waveguide design were fabricated and characterized. The use of a rather narrow waveguide core results in a remarkable low fast axis beam divergence of 44 deg full-width at half-maximum. For single emitters, a continuous-wave (CW) output power of nearly 2 W has been observed. We have achieved 16.9 W in CW mode at a heat sink temperature of 20 deg C. The efficiencies of more than 25% are among the highest values reported so far for GaSb-based diode lasers, and allow the use of passively cooled and, thus, less expensive heat sink technologies.