The present invention describes a microresonator that can be used as a 1:f variable coupler in a unit cell. It is described how a cascade of unit cells can be used to form a tunable, higher-order RF-filter with reconfigurable passbands. The disclosed filter structure can be utilized for the narrowband channelization of RF signals that have been modulated onto optical carriers. It is also disclosed how to utilize add/drop capabilities of the contemplated microdisks to confer connectivity and cascading in two dimensions. The present invention can conveniently provide a wavelength division multiplexing router, where an array of unit cells as provided herein can form a programmable optical switching matrix, through electronic programming of filter parameters.