Design of a Flexible-Grid 1 × 2 Wavelength-Selective Switch Using Silicon Microring Resonators

In this paper, a compact integrated flexible-grid 1 × 2 wavelength-selective switch is proposed. The device is designed by utilizing a structure with nine reconfigurable add-drop silicon microring resonators. Using thermal tuning, the transmission spectra of silicon microring resonators are coherently combined to provide adjustable bandwidths as desired. The operation principle and detailed analysis of the designed device are presented. Calculation results show the bandwidth tuning for the spectrum with the large bandwidth varies from 0.56 to 4.09 nm and the bandwidth tuning for the spectrum with the moderate bandwidth ranges from 0.38 to 2.64 nm. The integrated flexible-grid 1 × 2 wavelength-selective switch with the maximum bandwidth tunability has a maximum crosstalk of -11.5 dB.