The Research Of Distributed Temperature Monitoring System Based On The Fiber Bragg Grating Sensor

Structural health monitoring of large-scale projects has important scientific significance. Fiber Bragg grating sensors with anti-electromagnetic interference and don’t affected by light source stability, easy to constitute a sensor network by wavelength division multiplexing to achieve quasi-distributed measurement, making it has great application in the field of petroleum and petrochemical also in the field of bridge engineering. The fiber grating is based on wavelength-coded, and can couple with fiber easily. The applied force or change in temperature will cause the wavelength drift, by detecting the wavelength drift to demodulate of the temperature or strain. It can reach high sensitivity and accuracy.First we discussed the photosensitivity and optical properties of the fiber grating, and then make theoretical analysis of fiber grating mode coupling equation, also describe the preparation of FBG and fiber grating temperature sensing theory. In the experiment, through the application of WDM technology, we use fiber Bragg grating temperature sensors constituting a quasi-distributed sensor networks to high temperature furnace in monitoring the temperature. We discuss the temperature response relationship of fiber Bragg grating sensors in monitoring and design layout of the monitoring environment sensor network, and make a simple design of demodulation system. We use the MOI company’s SM130demodulator and fiber grating temperature sensor to make distributed temperature monitoring, and use electronic thermometer to do a comparison of the data. Through the experimental analysis of distributed temperature monitoring network in the large tank health monitoring environment, we predict there are good prospects for application.We also discussed the packaging technology of Fiber grating temperature sensor. In the first, describe the theory of the common package, and then through the experimental comparison of the sensitizing package, without increasing the temperature sensitive packaging and bare gate, we make the comparison of response sensitivity relationship. In the last, we proposed in a practical engineering environment, there is better to use the encapsulated fiber Bragg grating in monitoring, it can achieve protection of the grating and reduce the impact of environmental factors...