High power continuous wave operation of mid-infrared quantum cascade lasers

In recent years laser emission from unipolar quantum cascade (QC) structures has been demonstrated in a wide range of wavelengths and temperatures. Continuous wave (CW) operation has also been reported, but with limited output powers (a few tens of mW). We present here the results obtained on a mid-infrared QC laser, whose design has been carefully optimized in order to maximize the injection efficiency and the gain. The device employs a three-well vertical-transition active region with a CW light modulation