High power type-i GASB-based lasers

Challenges and limitations in development of the mid-infrared room temperature CW operated diode lasers with wavelength longer than 2 μm are discussed. The major breakthrough in terms of high power performance in this spectral range was achieved with type-I true quaternary InGaAsSb heavily compressively strained QW GaSb-based lasers. We have demonstrated 1 W CW at 2.5 μm, 500 mW and 160 mW CW at 2.7 and 2.8 μm, respectively. High power 2.3 μm linear laser arrays output 10W CW at room temperature. Experimental results show that there is no fundamental limitation to extend CW RT operating wavelength of these devices to over 3 μm spectral region. It is carrier leakage and material quality issues that limit device performance at wavelength longer than 2.5 μm. The role of Auger recombination is not decisive in type-I MQW GaSb-based lasers. We speculate that it is high differential gain and, as a result, low threshold carrier concentration that can account for muted effect of Auger on type-I GaSb-based laser performance. Dilute-nitride GaSb-based type-I QWs are proposed for development of CW room temperature operated lasers in spectral range 3-4 μm.