1. A method for determining switching configurations of idle cells to suppress cross-talk in photonic switching fabrics, the method comprising: identifying signal paths through an N×N photonic switching fabric, wherein the N×N photonic switching fabric includes N input ports, N output ports, and a plurality of photonic elements (PEs) positioned in between the N input ports and the N output ports, the plurality of PEs being arranged in a central stage of 2×2 PE blocks, a first set of PE stages positioned in between the central stage and the N input ports, and a second set of PE stages positioned in between the central stage and the N output ports; identifying idle PEs in the plurality of PEs, the idle PEs being inactive when the N×N photonic switching fabric is configured to provide the signal paths; determining a cross-talk suppression map for the idle PEs in accordance with a recursive algorithm, the cross-talk suppression map specifying active configurations for at least one idle PE to reduce cross-talk between the signal paths; and either sending, by a device, the cross-talk suppression map to a controller of the N×N switching fabric or configuring, by the device, the N×N switching fabric in accordance with the cross-talk suppression map.