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

We report on the realization of quantum cascade (QC) lasers based on strain -compensated InxGa(1-x)As/In(y)A((1-y))As grown on InP substrates using mol ecular beam epitaxy. X-ray diffraction and cross section transmission elect ron microscopy have been used to ascertain the quality of the QC laser mate rials. Quasi-continuous wave lasing at lambda approximate to 3.54-3.7 mum a t room temperature was achieved. For a laser with 1.6 mm cavity length and 20 mum ridge-waveguide width,quasi-continuous wave lasing at 34 degreesC pe rsists 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 compa rable wavelength.