We present a design of quantum cascade laser arrays made of ridge-waveguide devices in which the emission frequency can be electrically switched between several specified values. Our approach relies on fabricating multiple independently-biased distributed feedback grating sections along the laser ridge waveguides. Switchable single-mode lasing from the laser facet is achieved by balancing the injection pumping of the different grating sections. Our method provides a robust solution that can increase the tuning bandwidth of the quantum cascade laser arrays without increasing the size of the array emission aperture.
