Design Of Real-time Demodulation System For Optical Fiber Sensing Based On MATLAB GUI

With the rapid development of artificial intelligence and networks,fiber optic sensors have ushered in a period of rapid development.Wavelength demodulation-based fiber optic sensors have the advantages of low cost and simple structure,However,demodulators and micro-spectrometers currently used in laboratories for fiber optic sensing often need to export data offline to a computer for processing,which makes it difficult to realize real-time demodulation of spectral data.Based on the above problems,this paper designs a program based on MATLAB software to call the collected spectral data in real time and constructs a real-time demodulation interface through GUI to realize the real-time demodulation of fiber optic sensors.The main research contents of this thesis can be summarized as the following three points.(1)The software design process of the real-time demodulation system is introduced.The real-time demodulation interface based on MATLAB software is built to address the shortcomings of the spectrometer or demodulator currently used in the laboratory,which is difficult to achieve real-time monitoring.Firstly,the real-time data acquisition and recall are realized,and then the real-time display and monitoring of spectral data are realized according to the graphical user interface(GUI).Finally,the real-time demodulation system is designed according to the different sensors monitored to realize the real-time demodulation of fiber optic sensors.(2)Design a real-time demodulation system based on the fiber optic sensor with simultaneous AC/DC measurements.To address the problem that the grating demodulator currently used in the laboratory can only achieve simple temperature and stress demodulation,through the serial port grating demodulator data into the computer in real time,the use of MATLAB data processing to achieve complex grating demodulation.A current sensor combining fiber Bragg grating(FBG)and giant magnetostrictive materials(GMMs)is designed to achieve simultaneous AC and DC measurements.The principle that this fiber optic sensor can achieve simultaneous AC and DC measurements is analyzed,and then the ability of the sensor to measure AC and DC simultaneously is verified in experiments.Finally,real-time demodulation of the spectral data is achieved by importing the data into the computer through the serial port to realize real-time monitoring of AC and DC.(3)Design of real-time demodulation system based on fiber optic SPR temperature sensor.For the problem that Spectra Suite,the supporting software of microspectrometer USB4000,cannot realize real-time demodulation of the fiber optic sensor,the spectral data are continuously saved to a folder,read by strcat function,and design the real-time demodulation interface.The effects on the sensor performance before and after fitting the spectral data were analyzed.The sensor utilizes a refractive index-temperature conversion medium,polydimethylsiloxane(PDMS),coated on an optical fiber SPR sensor for temperature sensing.Finally,the real-time demodulation interface is designed by MATLAB GUI and applied to the real-time monitoring of temperature.