Fiber Bragg Grating Wavelength Demodulation System And Experimental Research

Since its invention，the optical fiber Bragg grating(FBG) has obtained a fast developmentas its advantages. The key technology of FBG sensing lies in the accurate demodulation ofthe Bragg reflection wavelength. We can say that the measuring accuracy of thedemodulation module directly determines the detection precision of the sensor system.The project is based on the need for the key technology of the fiber optic seismicmonitoring basic research in the major engineering disaster warning. As the foundation ofthe fiber Bragg grating sensing technology in the application of the water pipe inclinometerlever measurement, this article mainly studies and designs a water pipe inclinometerdemodulation system based on FBGA wavelength demodulation module. The system wehave designed has high accuracy, visualization, easy operation, small size, etc.This article firstly introduced the sensing fundamental of FBG including description oftheoretical model, analysis of strain sensing model and temperature sensing model, andcarried on an analysis of FBG wavelength demodulation technology and multiplex techniqueof FBG sensing network. Then, it introduced an overall scheme of the design of the fiberBragg grating pipe inclinometer demodulation system, and analyzed the working principle ofthe system. And after that, it introduced the PC software design of pipe inclinometerdemodulation system which includes module settings, the FBG parameters calibration,waveform display, wave data and measurement parameter display, and the real-time displayof the water pipe inclinometer slope angle.We built the water pipe inclinometer demodulation system on the experimental platformto verify the accuracy, the sensitivity, and resilience of the demodulation system. The resultsshow that the absolute error of the measured data between the demodulation system and thefiber Bragg grating demodulation instrument is only0.6pm/mm under the same testconditions, and this illustrates that the accuracy of the demodulation system is very high.Within the scope of about10mm, the demodulation system shows high linearity, and itsexperimental sensitivity can be0.1284nm/mm. The resilience of demodulation system isvery good which can meet the needs of the project.