All-optical switching of a single wavelength in a silicon-based ring-assisted Mach-Zehnder interferometer

We theoretically investigate for the first time an all-optical switch using a silicon-based ring-assisted Mach-Zehnder interferometer (RAMZI), where the switch mechanism relies on Raman-induced loss. Compared to the conventional standalone microring resonator (MRR) switches, the RAMZI structure improves the fabrication tolerances by removing the critical coupling requirement for the MRR without compensating the switch performance. Moreover, the RAMZI structure provides an improved switching speed (5× faster) by shortening the photon lifetime of the MRR. Finally, the inverse Raman scattering of silicon guarantees a single wavelength selectivity for the switch.