Abstract: An optical switch for use in a WDM communication system is provided which includes a tiltable mirror assembly having a mirror and an actuator for orienting the mirror. At least one receiver is also provided for receiving an optical beam reflected from the tiltable mirror. A controller, which drives the actuator, includes an alignment mechanism having a common mode rejection arrangement, responsive to a signal received from the receiver, for adjusting the actuator to orient the tiltable mirror so that an optical beam reflected therefrom is coupled to the receiver with a particular efficiency.