A controller in an optical switch providing optical coupling of an optical signal between a source port and a target port employs, in at least one axis, gradient control using a feedback loop that compensates for alignment error between a source port and a target port in an optical switch. In at least one other axis, the controller generates a control input according to a control law that results in variable attenuation of optical coupling between the source port and the target port in the optical switch. A dither signal may be applied to the control input in the at least one other axis. Amplitude of the applied dither signal may be varied.