A low voltage micromachined optical switch by stress-induced bending

In this paper, a novel electrostatically actuated 2x2 fiber optic switch with very low operating voltage is presented. Using stress-induced bending of polysilicon plates, a vertical mirror is raised above the substrate. Electrostatic force is used to attract the mirror to the substrate to switch between the cross and the parallel states of the optical switch. The stress-induced curvature of the polysilicon beam substantially lowers the operating voltage of the switch. Large mirror displacement (300 mu m) and low operating voltage (20 V) are achieved simultaneously. Submillisecond switching time (<600 mu sec) and reliable operation (>14 million cycles) have been demonstrated. The insertion loss is measured to be 0.55 dB and 0.7 dB for single mode fibers in the cross and parallel states, respectively.