GaSb-based laser diodes operating within the spectra range of 2–3.5 µm

In this paper development of lasers operating in CW mode at room temperature at wavelength up to 3.4 μm is demonstrated. This is accomplished based on the use of quinary AlInGaAsSb waveguide with In composition 25%-32% as well as optimization of the waveguide thickness. GaSb based type I lasers with diffraction limited beam operate at 20°C and generate 9 mW of the continuous wave output power at 3.16 μm. We established that the increased valence band discontinuity of InAlGaAsSb QWs improved laser efficiency and the device differential gain with respect to concentration minimizing the contribution of Auger processes by reducing the threshold carrier concentration. We used high compressive strain in QWs for all structures to further improve confinement of holes in laser QWs.