Variable optical attenuator using parallel plate electrostatic actuator

Abstract

A micromachined variable optical attenuator (VOA) has been investigated. The VOA has two single mode fibers (SMFs) aligned with free space and a symmetric parallel-plate actuator with micro-shutter, which can control an amount of light by driving the actuator. In the work, the analysis of driving and optical performance of the VOA was performed, and the pull-in voltage could be reduced by decreasing the displacement of actuating range. The VOA that consistes of driving electrode, ground electrode, actuating micro-shutter, and mechanical stopper, was fabricated by using the Bosch deep silicon etching process with silicon-on-insulator (SOI) wafer. The actuating shutter was driven by electrostatic force. The threshold voltage of actuating shutter was close to 28 and 46 V at a spring width of 5 mum and 7 mum, respectively.