Total Internal Reflection-Based Free Space Optical Communication System

We present a free space optical communication system that uses electrostatically modulated microelectromechanical systems (MEMS) structures coupled with a glass total internal reflection-type corner cube retroreflector (CCR) as a nonemitting data transmitter. MEMS structures consists of an array of light scattering membranes fabricated on silicon-on-insulator wafer. The MEMS structures are bonded to a glass lid with a transparent conductive indium tin oxide film using flip chip bonding. The chip is aligned and bonded to a passive glass CCR using an ultraviolet (UV) epoxy with an accuracy of 20-30 arc-s. The MEMS structures can be modulated either toward or away from the bonded glass, thus disrupting evanescent energy delivered from a probing laser beam. Retroreflective optical communication over 300 m was achieved using an interrogating 635-nm laser.