Fiber Grating Vibration Sensor Systems And Their Applications

As one of the most developed passive fiber devices, Fiber grating has function of reflection to very wavelength, and its wavelength changed with temperature and strain., and has excellent filter properties, temperature and strain response, which is a novel fiber photonic device with rapid development in these years and has broad application in the fields of fiber communication and fiber sensor.Fiber Bragg grating (FBG) sensor is a new type of sensor, which has the advantages of resistance to high voltage, lightweight, low loss, non-sensitivity to the environment, small volume, high Signal-to-Noise and high sensitivity, anti-electromagnetism, better insulation and large bandwidth, being used as sensor and transmitting medium at the same time, and it is more easy to realize multipoint or distributed measure. Yet, the new technologies have been born only few years, so they should be researched and developed more deeply.In this thesis, the development of FBG technology is described and the applications of FBG in fiber sensor systems are studied. A detailed discussion based on the coupled-wave theory was described to explain the optical characteristic and sensor principle of the fiber grating, and the characteristic and application of FBG sensor were narrated. Focusing on the principle of FBG fabrication, its structural characteristics and sensing principle, deep research has been carried out in this thesis. Furthermore, the paper has made some research in the fields, such as FBG vibration sensor, wavelength demodulators, and the applications of FBG sensor systems. By the use of temperature and strain mechanisms of FBG sensors, the new projects of Vibration sensors technology are brought forward, which establishes theoretical foundation for measuring vibration by fiber Bragg grating sensing technology and has definite instructional meaning for designing fiber Bragg grating vibration sensor. The contributions of this paper are:1. On basis of analyzed the principle of FBG sensing technology, the emphasis was laid on the feasibility of using FBG sensors to measure vibrations. The design factors of FBG vibration sensors were confirmed and the general design method brought forward.2. Analysis of the functional mechanism of FBG coupled mode theory was given. The reflection and transmission formulas were deduced, as well as the expression of the half...