Research On EFPI Sensor Demodulation System Based On FPGA

The Extrinsic Fabry-Perot Interferometer optical fiber sensor,because of its outstanding anti-electromagnetic interference,high precision,high insulation performance,light weight,small volume and long distance transmission,has been widely studied at home and abroad,involving the aerospace,medical,mine,high voltage power supply and other fields;for EFPI fiber optic sensors,to achieve the demodulation of the sensor signal,demodulation technology is the key to the measurement accuracy and measurement speed,so based on EFPI The research of sensor demodulation system is of great significance to promote the development of various fields.The object of this paper is high temperature and pressure sensor based on MEMS technology,which is mainly used to measure the change of pressure at high temperature.The EFPI sensor signal of this structure is realized by high speed programmable logic device(FPGA)real-time demodulation technology.Design a complete set of optical fiber signal demodulation system,including the sensor module,real-time demodulation hardware module,FPGA logic module.The sensor module mainly builds an optical system,which can transmit the sensor signal to the FPGA through the light source,the tunable filter and the etalometer.The real-time demodulation hardware module mainly designs the hardware system,through the high-speed ADC,DAC,programmable op amp,to achieve the photoelectric conversion and sensing module control;FPGA logic module,the preparation of demodulation logic code,to achieve a logical algorithm and data acquisition;the same time,this light source for the phenomenon of light power instability,Hardware-based optical power compensation method,and the compensation method for Matlab simulation and logic programming to achieve,and finally the algorithm logic package IP core,the completion of the optical power compensation.Peak solution,the reference to the fixed threshold of the centroid method to find the peak and interpolation method real-time calibration,through FPGA logic programming simulation,encapsulated into IP core.The experimental results show that the optical power compensation and peak finding method are feasible and the result is reliable and accurate.Finally,this paper introduces the application of MEMS EFPI sensor demodulation system,summarizes the results of the paper and prospects for further research in the future.