Modeling of optical signal processing based on injection-locked broadband quantum cascade lasers

An all-optical signal processing approach has been presented which relies on gain competition between interconnected wavelengths in a broadband QCL. It has been shown that optical injection-locking, as the physical mechanism which modifies the inter-coupling between widely separated wavelengths, induces spectral reshaping through suppressing or raising the output intensity at designated wavelengths. Our developed model which is based on an experimental demonstration of an ultra-broadband QCL reveals a correlation between the intensity and modulation response of the injection-locked wavelengths. Also, it has been shown that logic operations and extremely wideband wavelength conversion between the mid and far-IR spectral regions of the laser can be accomplished.