A Piezoelectric-Driven Three-Dimensional MEMS VOA Using Attenuation Mechanism With Combination of Rotational and Translational Effects

A gold-coated silicon mirror (5 mm 5 mm) actuated by piezoelectric (PZT) cantilever beams has been investigated for variable optical attenuator applications. The device is micromachined from a SOI substrate with a 5 μm thick Si device layer, with multilayers of Pt/Ti/PZT/Pt/Ti deposited as electrode materials. A large Si mirror plate and 110 arrayed PZT cantilevers arranged in parallel are formed after the release process. The ten cantilevers are designed to be electrically isolated from one another. A dual-core fiber collimator is aligned perpendicularly to the mirror in a 3-D light attenuation arrangement. Thus, three modes of attenuation mechanisms were investigated based on rotational and translational effects. A dynamic attenuation range of 40 dB is achieved at 1 V and 1.8 V for bending and torsional mode, respectively.