Research On Optical Fiber Strain Transfer Relations And FBG Sensor Performance Degeneration

Optical fiber sensors have the advantages such as small size, low weight, immune toelectromagnetic interference，high sensitivity，reliability and easy to reuse etc,so it is widely used inthe area of Structural health monitoring and a hot research topic in recent years However, FBGsensors should not avoid performance degenerate when work in the bad environment, which leads tomistakes and makes wrong judgments. We will take a series of studies to solve the above problems，which contain these factors that affect the performance characteristics of FBG sensors of temperaturesuch as corrosion, non-uniform temperature/strain field and bending etc. If these problems canperfectly be solved, it will promote the development process, and the application of FBG sensingsystem will be greatly improved. The main research contents as follows，(1) The theoretical analysis of the Optical fiber sensors sensing principle, and on the basis of theanalysis of the temperature/strain sensing principle of Optical fiber sensors, and the experimentalresearch. According to the simulation analysis of the coupled-mode theory I analyze the influence ofthe Optical fiber sensors’ reflection spectrum、transmission spectra and grating parameters on theOptical fiber sensors reflection spectrum.(2) Establishing the Optical fiber sensors’ structure model, the strain transfer factor is proposedfor the FBG sensors and Photoelectric composite cable structure. The effect of various structuralparameters on the optical fiber sensor strain transmission capacity and the strain transfer characteristicwhen different forms and distribution of the strain effect on the Optical fiber sensors.(3) The theoretical analysis of the temperature affecting the optical fiber Bragg grating sensors’performance has been studied. Finally, I test the result of simulation.(4) To analyze the affection of cladding decrease on the Optical fiber sensors performance.Meanwhile, the problems about the effect of corrosive environment on the optical fiber sensors’performance and the applications of the FBG sensors eroded through the corrosion test also have beenstudied(5) Reflectivity spectrum of FBG is analyzed under different kinds of non-uniform strain andtemperature, some methods of reconstruction reflectivity spectrum have been introduced. Reflectivityspectrum of FBG is analyzed under varying degrees bend.