Room-temperature 2.5 μm InGaAsSb/AlGaAsSb diode lasers emitting 1 W continuous waves

We have characterized 2.5-mum-wavelength InGaAsSb/AlGaAsSb/GaSb two-quantum-well diode lasers that emit 1 W continuous waves from a 100-mum-wide aperture at a temperature of 12 degreesC. The threshold current density is 250 A/cm(2), and the external quantum efficiency near threshold is 0.36. The wall-plug efficiency reaches a maximum of 12% at a current of 2 A. Operating in the pulsed-current mode, the devices output nearly 5 W at 20 degreesC. These lasers exhibit internal losses of about 4 cm(-1) and differential series resistances of about 0.1 Omega. A broad-waveguide design lowers internal losses, and highly doped transition regions between the cladding layers and the GaSb reduces series resistance. (C) 2002 American Institute of Physics.