A novel microring resonator based on multi-Mach–Zehnder interferometers

Abstract A microring resonator (MRR) with an extended free spectrum range (FSR) based on multi-Mach–Zehnder interferometers (MZI) is proposed and the simulation is demonstrated. In the MRR, two straight bus waveguides are replaced by multi-MZIs to extend the FSR. The transfer matrix method and coupled-mode theory are adopted to derive the mathematic model of the multi-MZIs based MRR. A numerical simulation is carried out by the finite-difference time domain (FDTD) method. The simulation results show that the resonance peaks are suppressed at certain intervals due to multi-MZIs, an octuple quasi-FSR is obtained by a tri-MZIs based MRR. The key advantage of the proposed multi-MZIs based MRR is that the extended FSR is realized without having to add complicated auxiliary components or increasing the number of ring resonators.