Multistate latching MEMS variable optical attenuator

A multistate latching variable optical attenuator (VOA) is demonstrated using microelectromechanical systems (MEMS) technology. The mechanism is used to fix the position of a shutter inserted into the optical path between two single-mode fibers. The mechanism and fiber mounts are fabricated in 85 μm thick silicon using bonded silicon-on-insulator material, by deep reactive ion etching. The device can be continuously adjusted or latched into a discrete set of attenuation states using a rack-and-tooth mechanism driven by electrothermal shape bimorph actuators. Electromechanical and optical characterization is performed to demonstrate a latching VOA function, with a maximum attenuation of 30 dB.