Frequency combs and optical feedback in Quantum Cascade Lasers: a unifying theoretical framework

Abstract

We propose a unified theoretical framework for the frequency comb formation and optical feedback effects in semiconductor lasers. We use the quantum cascade laser as a suitable device to develop the framework unifying these two research areas, so far treated distinctly. We generate a novel feedback regime diagram and we provide a proof of principle that feedback can be used to induce and manipulate frequency combs, selecting their harmonic order. These results open a pathway towards new methodologies for hyperspectral imaging, multimode coherent sensing, and multi-channel communication