In-plane rotary comb-drive actuator for a variable optical attenuator

An in-plane rotary comb drive actuator was designed for variable optical attenuators (VOAs) that achieved large attenuation with fast response at low driving voltage. Actuator performance was improved by using a higher density of comb fingers for a smaller moment of inertia, serpentine flexure springs for a larger rotational angle, and symmetric spring arrangement for a higher radial shock resistance. A rotation of a tilted reflective mirror was used to further enhance the optical attenuation of VOA. The actuator, proposed with the size of 2 mm x 2 mm, achieved the bandwidth of 350 Hz and the deflection angle of 2.5 deg at 5 V, resulting in the maximum attenuation of 57 dB. (C) 2008 Society of Photo-Optical Instrumentation Engineers. [DOI: 10.1117/1.3013547]