A colorless, directionless ROADM includes a pair of contentioned add and drop wavelength-selective optical switches, an input wavelength-selective optical switch having one input port, and an output wavelength-selective optical switch having one output port. Unintended input-to-output port couplings, which appear in the “contentioned” add and drop switches, can be mitigated by the input and output wavelength-selective optical switches carrying the through traffic.