MEMS VOA based on torsional and bending attenuation mechanisms using piezoelectric cantilever integrated with 1×10 PZT thin film actuators

A gold coated silicon mirror (5 mm × 5mm) actuated by piezoelectric Pb(Zr, Ti)O₃ (PZT) cantilever beams has been investigated for variable optical attenuator applications. The device is micromachined from a SOI substrate with 5μm thick Si device layer, with multi-layers of Pt/Ti/PZT/Pt/Ti deposited as electrode materials. A large Si mirror plate and a 1×10 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 three-dimensional (3-D) light attenuation arrangement. Two modes of attenuation mechanisms were investigated based on bending and torsional effects. A dynamic attenuation range of 40dB achieved at 1V and 1.8V for bending and torsional mode respectively.