Research On Wavelength Characteristic Recognition And Detection System Of Fiber Grating

Fiber gratingis widely used in large composite structures, concrete monitoring, power industry, petroleum industry and smart materials performance monitoring because of its goodtemperature and train sensitivity and filtering characteristics. FBG sensors have multi-parameter sensing, distributed sensing, and other characteristics for environmental monitoring of large and complex structures and it often use sensor networks monitoring methods.Fiber grating sensing accuracy and sensor network distribution make the optical fiber grating sensor demodulation system become the focus of one of the difficulties of the current FBG sensing technology research.In this paper, the demodulation device reliability design and wavelength demodulation method and test system development conducted in-depth researchbased on the optoelectronic whole column optoelectronic imaging technology detection method and used a serial bus integration demodulation module and multi-channel optical switch control technology.The main contents are as follows:According to the optical fiber grating coupled mode theory and wavelength characteristic parameters,with the technical parameters of the grating to calculatecharacteristic parameters. By sampling the spectral curve characteristics experiment, analyze and summarize the recognition criteria wavelength peak location algorithm.Use Bragg wavelength characteristic parameters proposed multisensor grating peak positioning analysis method to improve the peak location algorithm computational efficiency.The peak point as the center and use the surrounding discrete data to explore the Gaussian fitting algorithm and polynomial fitting algorithm.Use Bragg wavelength characteristics and demodulation instrument spectral sampling sensor data features and explore the Gaussian fitting algorithm and polynomial fitting algorithm to demodulate FBG sensingcenter wavelength and the center wavelength demodulation for comparison analysis.Unified Modeling Language (UML) use case diagram, sequence diagram and class diagram for test system functional requirements, dynamic execution and programming aspects make the visual depiction.Development and design the fiber Bragg grating sensing system based on serial bus as the environment of Visual C++.NET.According to the site application requirements of demodulation device, designed sensor demodulation system overall architecture and select core optics of system. With the reliability control and communication of optical devices and detection system to design the circuit.In order to improve the stability of USB high-speed communication, adopt to signal integrity analysis method to analysis and design PCB board differential signal impedance control and crosstalk.Developed communication protocols between the demodulation device and the host computer and the overall control program of demodulation device, and developed a 16-channel fiber Bragg grating sensor demodulation devices.Connected demodulator and detection systems via the serial bus to test its demodulationspectrum continuous sampling, a single sample, the optical switch module with the demodulation sequence control software features.Tested the static and dynamic stability of ±6pm, measurement accuracy of 1pm.From the system working conditions and experimental results to demonstrate the reliability and stability of the system.