Continuous-wave operation of quantum cascade lasers above room temperature

Abstract

Continuous wave operation of quantum cascade lasers is reported up to a temperature of 311 K. Fabry-Perot and DFB devices were fabricated as buried heterostructure lasers with high-reflection facet coatings. Junction-down mounted FP-lasers emitted up to 17 mW and 3 mW of optical power per facet under continuous wave operation at 292 K and 311 K, respectively. The DFB-devices could be operated up to 253 K on a thermoelectric cooler at an emission frequency of 1114 cm^-1 with a side mode suppression rate better than 30 dB. Grating-coupled external cavity quantum cascade lasers based on a bound-to-continuum active region featuring a broad gain spectrum demonstrated frequency tuning of ~10% from 1036 cm^-1 to 1142 cm^-1 with average output power between 0.15 and 0.85 mW under pulsed operation at room temperature.