GaSb-based 2.X µm quantum-well diode lasers with low beam divergence and high output power

We report on GaSb-based 2.X µm diode lasers with an improved waveguide design, leading to a reduced beam divergence in the fast axis of 44° full width at half maximum (FWHM), compared to 67° FWHM of a conventional broadened waveguide design. 2.3 µm ridge-waveguide lasers with the improved epitaxial design showed, besides the narrow beam profile in the fast axis, an excellent slow axis beam quality [M(exp 2)