Low Power Consumption Distributed-Feedback Quantum Cascade Lasers Operating in Continuous-Wave Mode above 90°C at λ ∼ 7.2 μm**Supported by the National Basic Research Program of China under Grant No 2013CB632801, the National Key Research and Development Program under Grant No 2016YFB0402303, the National Natural Science Foundation of China under Grant Nos 61435014, 61627822, 61574136 and 61306058, the Key Projects of

Abstract

We report on the design and fabrication of λ ∼ 7.2 μm distributed feedback quantum cascade lasers for very high temperature cw operation and low electrical power consumption. The cw operation is reported above 90°C. For a 2-mm-long and 10-μm-wide laser coated with high-reflectivity on the rear facet, more than 170 mW of output power is obtained at 20°C with a threshold power consumption of 2.4 W, corresponding to 30mW with a threshold power consumption of 3.9 W at 90°C. Robust single-mode emission with a side-mode suppression ratio above 25 dB is continuously tunable by the heat sink temperature or injection current.