Dense multi-channel optical waveguide switch based on micro ring resonators

This study proposes a dense multichannel optical waveguide switch based on micro ring resonators (MRRs). The proposed design is achieved by cascading five MRRs of the same structure and the phase difference between two bus waveguides that are evanescently coupled to every two MRRs is purposely set at either 0 or π in order to minutely adjusting the positions of the corresponding resonant wavelengths of the MRRs. Our proposed structure is capable of controlling ON/OFF signals associated with four optical channels. Our study finds that the resonant channel spacing is less than twice the full-width-at-half-maximum of an individual optical signal. Furthermore, among 16 different combinations of output spectra obtained, the ON/OFF signal contrast of each optical channel could reach up to-29.68 dB.