An electromagnetically actuated bi-stable MEMS optical microswitch

Abstract

An optical microswitch with electromagnetic actuation was developed and tested. The system consists of a micromachined mirror fabricated on one silicon wafer and a magnetic actuation system fabricated on a second. A spacer defines the appropriate distance between the wafers. The bottom wafer carries the magnetic active part consisting of two pairs of coil systems and flux guides. The top wafer contains the poly silicon mirror suspended on a pair of torsional beams as well as a magnetic ring for flux closure. Exciting one of the coil systems exerts a force on the corresponding flux closure pulling it downwards to the actuator system and tilting the mirror in the respective direction. Bumps on top of the magnetic pole surface restrict the mirror's movement. The optical switch a designed for a total rotational angle of /spl plusmn/5 degrees.