Passive fiber optic position sensor with digital encoding

Position sensors are ubiquitous in many industrial environments. Currently, resolvers, LVDTs, and electro-optic encoders are common. We report on fiber optic rotary and linear absolute position sensors developed for the aerospace industry that have broad potential. The use of fiber optics in sensors has many well known advantages including immunity to electromagnetic interference, remote positioning of the sensors on very long leads, reduced size, and increased tolerance to harsh environments. In addition, the sensors reported here encode the position information on a serial digital bit stream that interfaces easily with digital electronics and decreases sensitivity to lead fiber losses. This paper reports on the development of a class of passive fiber optic rotary and linear encoders for use in aerospace and industrial applications.