Low-threshold, low beam divergence GaSb-based quantum-well diode-lasers emitting in the 1.9 to 2.4 /spl mu/m wavelength range

Here we will present a new design for the vertical waveguide structure of (AlGaIn)(AsSb)-based diode lasers leading to a reduced beam divergence in the fast axis of only 44/spl deg/ full width at half maximum (FWHM), compared to 67/spl deg/ FWHM of a standard broad waveguide design. Uncoated ridge-waveguide diode lasers emitting at 2.3 /spl mu/m with a 1000/spl times/64 /spl mu/m/sup 2/ geometry showed a threshold current density of 180 A/cm/sup 2/ (or 60 A/cm/sup 2/ per QW), which is among the lowest values, reported for GaSb-based diode lasers.