Design And Research Of FBG Sensors

Fiber Bragg Grating (FBG) sensor, which uses the property that the Bragg wavelength is sensitive to temperature and strain, is a new kind of fiber optic sensor. Fiber Bragg Grating(FBG) sensor is a passive and electroless device which has some specific characteristics such as immune to electromagnetic influence, long transmission distance, easy to implement large-scale distributed network measurement by using technologies as wavelength division multiplexing, time division multiplexing and space division multiplexing. Therefore, FBG sensors have been demonstrated in a wide variety of fields, such as bridge engineering, petrochemical engineering, advanced aircraft and space vehicles, and also have been wildly used in explosive and high electromagnetic environments.In this paper, the Fiber Bragg Grating is taken as the object of study and studied its sensing technology in the theoretical and experimental methods. Main contents of this article are:A new high-sensitivity fiber Bragg grating temperature (stress) sensor packaging by a opening loop structure(PMMA) is designed and theoretical and experimental studies are made on temperature and stress sensitization packaging technology of fiber Bragg grating sensor. The experiment of the study on sensor is taken with the temperature and stress range of 22℃ 82℃and 0 10N ,and final result of the experiment is that the temperature sensitivity is 9.2×10^-5 /℃, 12 times of the bare FBG; the stress sensitivity is 1.057×10^-4N, and the transfer factoη= 0.64 comparing with the theoretical value; the center wavelength's curve of the grating responding with the temperature and stress shows good linearity and repeatability.A new measurement scheme of fiber Bragg grating is proposed and demonstrated which the temperature and stress parameters can be measured at the same time using one fiber Bragg grating. Half of the fiber Bragg grating is pasted on the basement of the PMMA with a large coefficient of thermal expansion, and the other half is not in this scheme. Temperature sensing characteristics is analyzed and studied when the stress is constant .The matrix of the changing relation between the wavelength and the stress/temperature can be obtained according to experimental results.