A High-Speed Silicon-Photonics WDM Switch for Optical Networks Applications

This article introduces the design of a novel high-speed silicon-photonics hitless switch that adheres to wavelength-division multiplexing (WDM) standards for channel 3 dB bandwidth, channel free spectral range, crosstalk, shape factor, and dispersion. The design combines the advantages of two structures, a compound ring resonator structure, and a Mach–Zehnder interferometer (MZI) modulator. The mathematical treatment for the proposed device is detailed, and two designs are presented. For a switch of five ring resonators, the through (drop) channel 3 dB bandwidth is 60 GHz (38 GHz), channel crosstalk is −24 dB (−24 dB), dispersion is 22 ps/nm (21 ps/nm), shape factor is 0.66 (0.5), and insertion loss is 0.3 dB (1.7 dB). For a switch of nine ring resonators, the through (drop) channel 3 dB bandwidth is 59 GHz (38 GHz), channel crosstalk is −37 dB (−24 dB), dispersion is 28.5 ps/nm (29 ps/nm), shape factor is 0.8 (0.73), and insertion loss is 0.3 dB (2.3 dB). For the five-ring design, the switch-on/off ratio is 30 dB, and for the nine-ring design, it is 31 dB. For both designs, the switching speed is 100 GHz.