Modulation And Demodulation Technology Of White Light F-P Fiber Sensor

An optical fiber strain sensor based on white-light interferometric principle is designed in this paper. It has more advantages, such as low cost, high stability and high anti-interference. It can be manufactured and put into use in many field.The principle of white-light interference for strain measurement is analyzed in theory, the optical fiber strain sensor system based on white-light interferometric principle of Fabry-Perot cavity and spectrum instrument is designed. It primarily consists of optic paths and photoelectric circuits. The part of optic paths includes optical fiber strain sensor, lamp-house, optical fiber coupling instrument and light dispersion equipment. And the part of photoelectric transform circuits refers to linear CCD. It includes driving circuits, signal processing and displaying circuits of CCD. In the system designing,the plane reflect grating is adopted to dispersion light. It can decrease losing of light energy. The important part in photoelectric transform circuits is design of driving circuits and signal processing circuits about linear CCD. The time order driving circuit of CCD are designed and debugged with CPLD (Complicated Programmable Logic Device), which make the whole driving circuit's volume very small, shorten design period, modify design at any time, and enhance reliability and agility of circuit. The emphases in this paper is that the modulation and demodulation system of optical fiber sensor is designed and made, and the experiments of temperature characteristic of optical fiber strain sensor are made. The result shows that the designed optical fiber strain sensor is of highly precision and highly sensibility under careful design and reasonable facture. Finally, the problems in the design of optical fiber strain sensor modem and the further research direction and measure are pointed out in this paper.