High-performance strain-compensated InGaAs/InAlAs quantum cascade lasers

Abstract
We report on the realization of quantum cascade (QC) lasers based on strain-compensated InxGa(1-x)As/InyAl(1-y)As grown on InP substrates using molecular beam epitaxy. X-ray diffraction and cross section transmission electron microscopy have been used to ascertain the quality of the QC laser materials. Quasi-continuous wave lasing at ë≈3.54-3.7 µm at room temperature was achieved. For a laser with 1.6 mm cavity length and 20 µm ridge-waveguide width, quasi-continuous wave lasing at 34 °C persists for more than 30 min, with a maximum power of 11.4 mW and threshold current density of 1.2 kA cm-2, both record values for QC lasers of comparable wavelength.