Crystalline silicon tilting mirrors for optical cross-connect switches

This paper discusses a two-piece approach for fabricating two-dimensional (2-D) arrays of tilting MEMS mirrors with application in very-large optical cross-connect switches. In the new process, a two-sided etching of silicon-on-insulator (SOI) wafers is used to create crystalline mirrors on a first wafer that is later aligned and bonded to a separate wafer containing the activation electrodes, traces, and bond pads. The approach allows a very close spacing of mirror elements and a very simple design for the mechanical structures, and also greatly simplifies wire routing.