Room temperature continuous-wave operation of a dual-wavelength quantum cascade laser

We report on the design and fabrication of a dual-wavelength switchable quantum cascade laser (QCL) by optimizing the design of a homogeneous active region and combining superposed distributed feedback gratings.Coaxial, single-mode emissions at two different wavelengths were achieved only through adjusting the bias voltage.Room temperature continuous-wave operation with output powers of above 30 mW and 75 mW was realized for single-mode emission at 7.61 μm and 7.06 μm, respectively.The simplified fabrication process and easy wavelength control of our designed dual-wavelength QCL make it very attractive for developing miniature multi-species gas sensing systems.