Research Of Fiber Grating Sensor Wavelength Detection And System Of Demodulation

From the optical communication technology has made great progress since the 1960 s, the corresponding optical fiber technique and technology also obtained the good development, and the optical fiber sensing technology is also gradually attention by people, Fiber Bragg Grating sensing technology is a new research hotspot in the field of optical fiber sensing. Thanks to the continuous innovation and development of the fiber Bragg grating writing technique, can realize the mass production of fiber grating, With the research of the sensing technology, and with its small volume, strong ability of anti-electromagnetic interference good corrosion resistance, high sensitivity, etc. The fiber grating sensors are being more and more applied to the field of civil engineering, energy and chemical industry, aviation, electric power monitoring and other fields.The performance of the fiber grating sensor demodulation system is the most important one of determinants to determine application of the sensing technology, As a wavelength modulator, how to demodulating tiny wavelength change is very important. In this paper, after studying the fiber grating sensing principle and demodulating technology, I further studied the wavelength demodulation algorithm, and made improvement on the basis of the existing algorithms, also designed a set of demodulation system combined with FPGA and NIOS soft core to implement the algorithm.This article main research content is:1. To study the optical fiber sensing and optical fiber grating sensing technology and the development of the status quo, research is mainly focused on the principle of fiber Bragg grating sensor and sensing technology and optical fiber grating sensor demodulation technology, based on the analysis of the advantages and disadvantages of various demodulation technology, we selected tunable F-P filter demodulation scheme, introduces the required optical device selection and principle of F-P filtering and designed a system of demodulation combined with FPGA and NIOS soft core.2. Using VHDL hardware description language design and verify the various control circuit based on FPGA module includes data collection and control,tunable F-P filter driver, the FIR low pass digital filter, configured the NIOS kernel.At the same time the article also introduced the development process of the platform used.3. The article designed the software of the system, Introduced in this paper, the demodulation system workflow, the wavelength demodulation algorithm of fiber Bragg grating sensor is studied and the paper improved Gaussian-polynomial algorithm and verify the feasibility and effect of the demodulation system,to use improved algorithm in this paper, the design of demodulation system wherein the configuration of NIOS in the kernel.