A MEMS device employed in an optical switch has a position sensor configured
to
determine mirror orientation in the device. The position sensor includes at least
one light sensor located under an etch gap defining the mirror in the switch. Change
of light intensity at each light sensor due to the change in separation corresponding
to the etch gap during mirror motion is measured and related to the mirror deflection
angle. Information about the angle may be used to provide feedback to the motion
actuator, which then may be operated to orient the mirror more accurately.
