Large Aperture MEMS Modulating Retro-Reflectors for Optical Communications

This proposal describes the design and manufacture of large modulating retro-reflectors (MRR) using Microelectromechanical Systems (MEMS) based optical modulators. In the proposed MRR device, a micromachined deformable mirror will serve as one facet of a corner cube retro-reflector which will allow intensity modulation of the retro-reflected beam. A characteristic of the MEMS device is that it can be made to act as a normal plane mirror, or it can be deformed using fast, low-power, electrostatic actuation. As part of the MRR, the device maximizes light intensity returned toward the source when the MEMS mirror is planar, and minimizes it when the MEMS mirror is deformed. As a result, the return beam intensity is modulated.The main challenge of the proposed work in development of the MEMS modulators is to scale up the size by a factor of 6 while maintaining good optical quality and modulation performance. To achieve the desired MRR optical performance thicker substrates will be used and custom MEMS foundry tooling will be utilized.The technical objectives are to (1) develop a fabrication process for the manufacture of MEMS modulators for use in MRRs with apertures of 38mm and 76mm, and (2) assemble and test the MRR devices.