3.4 μm diode lasers employing Al-free GaInAsSb/GaSb MQW active regions at 20 °C

Mid-infrared (3-5 μm) diode lasers are important for a wide range of applications, including gas sensing. GaSb-based type-I quantum well (QW) diode lasers are attractive choices for this wavelength range, due to their temperature stability and relatively lower operating voltage. In turn, these properties yield lower power consumption at threshold than quantum cascade lasers and interband cascade lasers, which is essential for portable systems. Excellent diode lasers, based on GaInAsSb QWs and lattice-matched AlGaAsSb barriers/waveguide layers, have been demonstrated below ~3 μm with high wallplug efficiency and low threshold currents.