Nonlinear Mach-Zehnder-Fano interferometer

We demonstrate that the interaction of loop and nonlinear Fano resonances results in a formation of hybrid resonant states in Mach-Zehnder-type interferometers, providing opportunities for an advanced phase manipulation. The nonlinear response of such structures can be greatly enhanced, leading to a low-threshold 100% switching operation. We further propose one of the possible realizations based on nonlinear photonic crystal circuits, suitable for optimal all-optical switching.