Temperature Compensation Method Of Optical Fiber Bragg Grating Sensing Test To Simulation Experiments

With the development of optic fiber communication, the technology of fiber Bragg grating (FBG) sensing has became a predominant one among traditional methods. Besides having the advantages of ordinary optic fiber sensors, it adopts wavelength coding, acquires the information of several parameters such as temperature and strain etal and achieves distributed sensing with only one fiber. Therefore they have been widely used in many fields.In this paper we simply introduced the characteristic of fiber grating and its application field, demonstrated its classification and manufacture method, studied the temperature and strain sensing properties of fiber grating, discussed its cross sensitivity, recommended the present schemes to the problem and adopted the fiber grating temperature compensation scheme without strain.Having experimently studied the temperature response characteristics of fiber Bragg grating. The result has proved that Bragg wavelength is linear to the temperature change very well. Its temperature sensitivity was 0.0132pm/℃, the coefficient of the Bragg wavelength and the temperature was 0.9995 which was not lethargic, so it proved that fiber Bragg grating had a good response to temperature.Furthermore, to overcome the cross sensitivity problem, we have designed a simple, economic and reliable temperature compensation scheme. From the experiment, we could see the squared error of Bragg wavelength was predominantly declined and so was the coefficient of the Bragg wavelength and the temperature ,which stated the Bragg wavelength shift was caused by the strain change after adopting the scheme. The strain sensitivity ranged from 0.15nm/N to 0.21nm/N.Combining the outstanding characteristics of the compensation scheme with the requirement of tabulate simulation model, we used the scheme to monitor strain change, the result showed the wavelength drift coincided with the deformation of rock layer without temperature affects, which proved the scheme was feasible to monitor strain change.