Study For High Precision Optical Fiber Angular Displacement Sensor Based On Sensitive Fabry-Perot Cavity

The detection of angle change with high accuracy ,plenty of range and high resolving power is one of detection means urgently in automatic control system of industrial control field. Because of the need of measure precision and the particularity of environment, existing angle sensor can not satisfy completely high accuracy and sensitivity , index of intrinsic safety needed in automatic control system, so study for new type of optical fiber angular displacement sensor has important meaning.Through the physical phenomenon of small angle change produced by rotating body, the property of small angle change is vertically transformed, so we can deduce linear function relation between angle and light intensity. Then we can succeed in measuring angles by means of photoelectric conversion and data handling. This is the basic thought of program research.In this program research, using the principal interference theory of Fabry-Perot resonant cavity fully and studying the property of micro-angle change produced by measured rotating body, we can transmit angle change into change of Fabry-Perot cavity length efficiently and light intensity signals into electric signals real time. At the same time, We analyse the difference between multi-beams interference and double beams interference under high reflectivity and low reflectivity. The theoretical analysis and imitating test have verified external temperature , stress, vibration, systematic noise and stability of light source influencing the major performance index of extrinsic Fabry-Perot interference system. From this thought so we put forward structural design of the sensor, produce technology , the handling of signal and the practical use problem of the sensor.The paper has analysed light source used in optical fiber sensor and its property ,positive and passive device in optic road, processing technique of output data, also made some beneficial suggestions.