Comparative study of three wavelength-routed four-port optical routers based on different polymeric microring routing elements

Abstract

Based on different basic routing elements, device architectures and design schemes of three kinds of four-port optical routers with the same routing function are studied. First, the structural parameters of the routing elements including cross-coupling one microring resonator (CCO-MRR), cross-coupling two microring resonators (CCT-MRR) and parallel-coupling one microring resonator (PCO-MRR), are optimized for single-mode transmission, low optical loss and phase-match between microring waveguide and channel waveguide. Then, detailed routing topologies of the three routers are presented, and a thorough comparison among them is made on their routing performances. The used MRR numbers of the CCO-MRR-based and PCO-MRR-based routers (four rings) are half of that of the CCT-MRR-based router (eight rings); the PCO-MRR-based router depicts the minimum insertion loss (0.02–0.6 dB); the CCT-MRR-based router reveals the minimum crosstalk (<−38 dB) and the best spectral selectivity; the CCT-MRR-based and CCO-MRR-based routers have the similar perfect N-stage cascading structure (still with four ports) for expanding the number of wavelength-channel to 3N; however, the PCO-MRR-based router cannot be cascaded easily because of too many unavoidable waveguide crossings. Provided fully utilizing the advantages of each router, the three routing devices can be used to meet different requirements in optical networks-on-chip.