Enhancement of the nonlinear response in Mach-Zehnder-Fano interferometer

We demonstrate the enhancement of nonlinear response and bistable switching in the Mach-Zehnder interferometer with side coupled nonlinear defects. Such system is known to exhibit high-Q nonlinear Fano resonances. Based on the introduced figure of merit the enhancement up to two orders of magnitude can be achieved compared to standard geometries. We applied these results for photonic crystal platform which allow for enhanced optical bistable operation.