New method decreasing drive voltage of torsion beam actuator micromechanical optical switches

Micromechanical optical switches have good quality for free-space optical cross connects, particularly in terms of the low insertion loss, low crosstalk polarization and wavelength-independence, and bit-rate transparency. In micromechanical optical switches, the electrostatic torsion beam actuator is widely used. But this actuator needs high-applied voltage. In this paper, using mechanical and electric characteristic, the relation between the translocation at the end of upper electrode and the applied voltage was derived. The. applied voltage is in direct proportion to the cube of the torsion beam thickness, and reduces with the shorten of original distance between two adjacent electrodes. The actuator with the inclined under electrode was proposed and fabricated with certain tilting angle (111) silicon. Theoretical analysis indicates that the drive voltage based on the slant under electrode actuator can decrease half of that based on the flat under electrode.