Microelectromechanical systems actuated small-scale retroreflectors for free space optical communications

This paper describes an electrothermal MEMS actuation device combined with small-scale retroreflective elements to produce a modulator suitable for use in a retroreflective optical free space communications system. The advantages and disadvantages of different retroreflective elements are compared, the steady state conditions of the device are investigated to give an understanding of operation, and the dynamics of the structure are investigated and compared when loaded with various retroreflective elements and when unloaded. Dynamic modelling and testing indicates practical operating frequencies extending to a few kilohertz.