Sb-Based Mid-Infrared Diode Lasers

In this paper we review recent progress achieved in our development of type-I GaInAsSb/AlGaAsSb quantum-well (QW) lasers with emission wavelength in the 1.74–2.34 μm range. Triple-QW (3-QW) and single-QW (SQW) diode lasers having broadened waveguide design emitting around 2.26 μm have been studied in particular. Comparing the two designs we have find that the threshold current density at infinite cavity length as well as the transparency current density scale with the number of QWs. Maximum cw operating temperature exceeding 50°C and 90°C has been obtained for ridge waveguide lasers emitting above and below 2 μm, respectively. Ridge waveguide diode lasers emitting at 1.94 μm exhibited internal quantum efficiencies in excess of 77%, internal losses of 6 cm−1, and threshold current density at infinite cavity length as low as 121 A/cm2 reflecting the superior quality of our diode lasers, all values recorded at 280 K. A high characteristic temperature TOof 179 K for the threshold current along with a value of T1 = 433 K for the characteristic temperature of the external efficiency have been attained for the 240–280 K temperature interval. Room temperature cw output powers exceeding 1.7 W have been demonstrated for broad area single element devices with highreflection/ antireflection coated mirror facets, mounted epi-side down. The latter result is a proof for the high power capabilities of these GaSb-based mid-ir diode lasers.