Mach–Zehnder wavelength selective switch embedded with microring resonators

Abstract

Abstract A wavelength selective switch is proposed for optical wavelength division multiplexing network applications with very short range interconnections. The proposed device uses a Mach–Zehnder interferometer configuration incorporating wavelength selective phase shifters composed of microring resonators between their two arms. Wavelength selectivity is provided by cascaded microring resonators, which are placed in proximity so that the increase in excess loss caused by the difference in resonant wavelengths can be minimized. An on/off switching ratio >20 dB is obtainable when the drop/through transmittance ratio of the cascaded microring resonators is >22 dB and the coupling efficiency deviation from 50% is <1% in the directional couplers constructing the Mach–Zehnder interferometer.