A novel driving scheme utilizing the resonance effect of the micro-mirror is presented to reduce the drive voltage of the silicon-based MEMS (microelectromechanical systems) torsion-mirror optical switch. A mixed bias of DC (direct current) and AC (alternating current) is adopted to drive the torsion mirror. Both the numerical simulation and experiment results show that the driving voltage of the optical switch is reduced by nearly 50%, from more than 270V to 130V.
A new kind of torsion-mirror optical actuators with compound driving structures is reported. The advanced compound driving structures are made up of plate-electrode couple drives and vertical comb drives, and are proved experimentally to be able to actuate mirrors to achieve not only large-range continuous rotation but also 90° rotation. A set of surface-and-bulk-mixed-silicon-micromachining process has been developed to manufacture the new torsion-mirror optical actuators in SOI wafers. In the processing, the comb fingers of about 180 μm in depth are produced. A synthetic coupling-loss model for the coupling system composed of the mirrors and the input and output fiber ends is obtained when the torsion-mirror actuators are brought into use as optical switches or attenuators, etc. for fiber communication applications.