Design And Implementation Of High-Speed Multi-Channel Fiber Bragg Grating Sensing Demodulation System

With the advent of the 5G era,the Internet of Things has ushered in unprecedented development opportunities.As the basis for building the Internet of Everything,the development of sensors is even more overwhelming.Optical fiber sensing is favored for its advantages of insulation and anti-electromagnetic interference,among which FBG sensors are the most widely used.FBG is a passive device sensitive to strain and temperature.Different packaging methods for FBG,combined with wavelength division multiplexing and time division multiplexing technology,can realize the sensing monitoring of various parameters.At the same time,FBG sensing is inseparable from demodulation equipment for signal acquisition and processing.The new generation of fiber grating sensing technology has the characteristics of high speed and large scale.At present,most high-speed demodulators on the market have limited demodulation frequency and cost.It is too high to meet the actual monitoring needs.Based on the above situation,the research on FBG related sensing demodulation technology is carried out in this paper,and a high-speed multi-channel fiber grating sensing demodulation system is designed and realized,which has important application prospects.The main research contents of this paper are as follows:1.The development status of FBG sensing demodulation technology at home and abroad is compared,the principle of FBG demodulation is studied,and the advantages and disadvantages of related demodulation technology and peak-seeking algorithm are analyzed.Considering high speed and high precision,the demodulation module based on transmission diffraction grating is selected.And an improved centroid peak-finding algorithm is used.The system architecture is designed.The system consists of the hardware part of the lower computer and the software part of the upper computer.2.The detailed software and hardware design of the fiber grating sensing demodulation system is given,and the selection of the corresponding modules and the construction of the optical path are completed;the hardware demodulation board is designed and completed.Including ADC acquisition circuit,USB2.0 data transmission circuit,serial communication circuit,temperature compensation circuit,optical switch switching circuit and power supply circuit;designed and completed the underlying ARM and FPGA drivers;designed and completed the demodulation circuit board card man-machine The interactive host computer software and the host computer interface can realize the configuration of parameters such as integration time and optical switch,and the display of system information such as wavelength and spectrum.Finally,the design of the database is completed,and the wavelength data can be stored persistently.3.The performance of the designed fiber grating demodulation system is tested.The experimental results show that the demodulation system designed in this subject has a demodulation stability of ±1pm,a demodulation accuracy of ±1pm,and the system has good temperature stability,which can realize four-channel optical path solution.The maximum demodulation frequency can reach 10kHz.