4×4 wavelength-reconfigurable photonic switch based on thermally tuned silicon microring resonators

Microring resonators (MRs) are important photonic devices for large-port-count photonic circuits owing to their micrometer-scale device sizes. We describe the implementation of a 4×4 wavelength-reconfigurable photonic switch consisting of eight tunable MRs fabricated on a less expensive material platform: silicon on insulator. Wavelength reconfiguration is achieved through independent thermo-optic tuning of MRs with localized Nichrome microheaters fabricated on the same silicon-on-insulator substrate. A free spectral range of 18 nm and a 3-dB linewidth of 0.1 nm were observed for the fabricated MRs with a diameter of approximately 10 µm. The switch device shows negligible channel crosstalk (<0.01 nm) and moderate switching response time (<1 ms). The switch can potentially be scaled up to benefit the development of large-scale integrated photonics.