Fig. 2: Implementation of each optical spectrum slicing (OSS) node as a first-order micro-ring resonator (MRR) within the reconfigurable photonic mesh.

The design utilizes eight programmable unit cells (PUCs): one PUC is set in the cross state (black) to guide light from the input port into the MRR loop, two PUCs act as tunable couplers (green) to couple light into and out of the loop, and the remaining five PUCs are set in the bar state (orange) to direct light within the loop and toward the output port (the drop port of the MRR). The central frequency of the MRR is tuned by utilizing a second phase shifter of a PUC within the loop, enabling the processing of different regions of the input signal spectrum.