High-power broadened-waveguide InGaAsSb/AlGaAsSb quantum-well diode lasers emitting at 2μm

We review our recent progress in the design and operation of 2-mu m InGaAsSb/AlGaAsSb quantum-well diode lasers. The devices have InGaAsSb quantum-well active regions and AlGaAsSb cladding layers, and all were grown lattice-matched to GaSb substrates using molecular-beam epitaxy. The broadened-waveguide (BW) design produces internal losses as low as 2 cm(-1), which leads to external quantum efficiencies as high as 53%. Single-quantum-well lasers with 200-mu m apertures and 2-mm-long cavities exhibit output powers of 1.9 W CW and 4 W quasi-CW. The lowest threshold current densities are 115 A/cm(2). Small arrays of similar multi-quantum-well diodes emit 10.6 W CW. The broadened-waveguide design should improve the performance of all mid-infrared diode lasers.