Large-Deflection Spiral-Shaped Micromirror Actuator

We present a new two-axis spiral-shaped micromirror manipulator developed for free-space optical switching. The actuator is an electrostatic actuator, which is composed of two different parts that are fabricated using conventional surface-micromachining processes and are then assembled. Instead of conventional monolithic self-assembling design approaches, these two parts are fabricated on two different chips and assembled using a spatial-mechanical approach. The design utilizes the increased flexibility of the spiral-shaped electrode and the zipping-effect technique in order to increase the maximum rotation angle. The footprint of the assembled device is 600 mum times 600 mum, and the height of the micropyramid is 200 mum. The switch is simulated using an energy method and a coupled electromechanical model. Its performance is measured statically using a reflection measurement approach. A continuous rotational actuation of 17deg has been achieved with an actuation voltage of 235 V.