Improved InGaAs/GaAsSb quantum cascade laser active region designs

Abstract

In0.53Ga0.47As/GaAs0.51Sb0.49 heterostructures lattice-matched to InP substrates were recently demonstrated to be a promising alternative for the design of mid-infrared and terahertz quantum cascade lasers (QCLs). The low effective mass for electrons in both compounds allows higher optical matrix elements and therefore more efficient devices. This work presents an advanced three-well active region and a four-well design with double phonon resonance for MIR InGaAs/GaAsSb QCLs, which both show improved temperature performance. Presently InGaAs/GaAsSb mid-infrared QCLs around 11.8 μm reach output powers of 1.2 W and a maximum operation temperature of 217 K. With the combination of the low effective mass and a moderate conduction band offset of 360 meV this material presents itself as an ideal candidate for improved THz QCLs. The first devices based on this material combination reach a maximum operation temperature of 102 K at an emission wavelength of 80 μm.