Above room temperature operation of short wavelength (lambda=3.8 µm) strain-compensated In0.73Ga0.27As–AlAs quantum-cascade lasers

We demonstrate the design and implementation of a broad-gain and low-threshold (Jth = 860 A/cm2 at 8 K) quantum-cascade laser emitting between 3.7 and 4.2 µm. The active region design is based on strain-compensated In0.73Ga0.27As–AlAs on InP. Laser operation in pulsed mode is achieved up to a temperature of 330 K with maximum single-facet output peak powers of 6 W at 8 K and 240 mW at 296 K. The temperature coefficient T0 is 119 K.