Communications: Fiber-optic transducers: Sensing and control systems based on fiber-optic conversion of input variables into modulated light signals are in development

Abstract

All fiber-optic transducers employ at least one light source for injecting a continuous signal into the fiber, a light detector for receiving the signal after the light has been modulated by a sensor, and electronics for converting the detected signal into a useful output. The two basic types of fiber-optic sensors are those in which the measured parameter causes a change in the transmission properties of the fiber itself and those in which the fiber acts merely as a conduit to carry light signals to and from the sensor. Development work is predominantly on transducers for military applications. For example, Sperry Research Center, Sudbury, Mass., is working on such systems for underwater sound and United Technologies Research Center, E. Hartford, Conn., for aircraft engine variables. Possible applications for fiber-optic transducers include sensing and control systems for farm equipment, industrial robots, commercial aircraft, ships, and buildings. Here qualities such as noise immunity, ruggedness, economy, and light weight give optical fibers a big advantage over electrical wiring.