Fabrication and characterization of torsion-mirror actuators for optical networking applications

摘要

Novel torsion-mirror actuators with monolithically integrated new fiber holding structures, which can feature self-fixing and self-aligning of optical fibers, are fabricated in regular silicon wafers as well as in SOI wafers by using the mixed micromachining based on the surface and bulk silicon microelectronics. The electromechanical performances of the actuators and the optical properties of their micro-mirrors are investigated experimentally and theoretically. The electrostatic yielding voltages for driving the micro-mirrors of the actuators to tilt from 0degrees to 90degrees spontaneously are in the range of 270-290 V and the minimum holding voltages for keeping the tilting angle of the mirrors to be in 90degrees are found 55 V or so when the thickness of the torsion-beams suspending the mirrors is about 1 mum. Theoretical analysis manifests that the yielding voltage is most sensitive to the beam thickness among the series of design parameters about the torsion-mirror actuator structures. The micro-mirrors of the actuators can cyclically vibrate 10(8) times at least between 0degrees and 90degrees, and their shortest actuating time can reach an estimated less than 2 ms. The surface roughness and its distribution of the micro-mirrors of the actuators are small and smooth, respectively, which is acceptable for wavelength division multiplexing applications basically. (C) 2003 Elsevier B.V. All rights reserved. [References: 7]