Optical control using an acousto-optic scanner

Abstract

Optical controllers exploit lightwave technologies to implement different control strategies. It is possible to replace many of the electrical and mechanical components found in traditional linear and nonlinear controllers with optical analogues that increase the speed of signal processing or enhance system sensitivity. These optical sensors, switches, communication links, and actuators are largely immune from electromagnetic interference, exhibit low signal attenuation, provide secure flow of information, and are safe in hazardous or explosive environments. In addition, the energy in the light beam is one of the easiest forms of energy to shape and transmit through free space. The fundamental characteristics of several ``control-by-light{''} systems are discussed in this paper. The proposed control system utilizes an acousto-optic deflector (AOD) to change the direction of the reshaped laser beam in response to the feedback error signal. The deflected beam strikes an array of photodetectors where each discrete detector represents a specific control action. One- and two-dimensional detector array configurations are explored for control. Although the controller designs can be implemented on optical breadboards. using off-the-shelf optical devices, recent advances in nanotechnology would allow similar micro-scale optical controllers to be fabricated at low cost.