Sb-free quantum cascade lasers in the 3–4 μm spectral range

Abstract

In this work, the design and implementation of Sb-free short wavelength strain-compensated quantum cascade lasers in the 3–4 μm spectral range is presented. Due to the presence of highly strained AlAs-barrier layers, the optimization of the epitaxial growth process is firstly discussed. The used active region design is then presented together with the observed laser performance. Watt-level room temperature emission at 3.3 μm is shown for Fabry–Perot devices and laser operation in pulsed mode is observed above 350 K. The laser performance is comparable with Sb-containing quantum cascade lasers. Spectral tuning of the lasers in an external cavity configuration over more than 275 cm−1 is achieved with an emission wavelength as short as 3.15 μm. For the first time in this spectral range, results on single-mode buried heterostructure distributed feedback lasers are shown.