An array of micromachined mirrors are arranged on a first substrate at the intersections of input and output optical paths and oriented at approximately forty-five degrees to the paths. An array of split-electrodes are arranged on a second substrate above the respective mirrors. Each split electrode includes a first electrode configured to apply an electrostatic force that rotates the mirror approximately ninety degrees into one of the input optical paths to deflect the optical signal along one of the output optical paths, and a second electrode configured to apply an electrostatic force that maintains the mirror position. Stability may be improved by using the first and second electrodes in combination to first actuate the mirror and then balance the forces on the mirror to maintain its position. Reproducibly accurate positioning of the mirrors requires either the use of active positioning control or of mechanical stops.