A system and method for controlling an optical filter is provided. The system and method includes dithering a delay of an optical path within an optical filter unit cell, measuring a position of a filter zero, measuring a position of a filter pole, or measuring positions of both a filter zero and a filter pole by observing an output of the unit cell when the delay is dithered, and using the measurement as feedback for maintaining the position of the filter zero at a desired position, maintaining the position of the filter pole at a desired position, or maintaining the positions of both the filter zero and the filter pole at desired positions.