Fiber Bragg Grating The Transients Strain Tester Data Processing Technology

Fiber Grating is a new kind of optical passive components, whose high sensitivity to strain make it widely used. As a result of high frequency signal produced by high speed objects and little amount of strain of the launching pipe, the traditional detection method can not meet the measurement requirements because of its inherent defects, such as being affected easily by the electromagnetic interference and hard to compose measurement network.In the thesis, the technique of strain measuring with Fiber Bragg Grating(FBG) is studied, the interferometic demodulation of dynamic strain signal is focused on, and a detailed analysis of phase generated carrier homodyne demodulation and three-step phase-shifting demodulation based on unbalance Mach-Zehnder interference system is taken. And a group of transient strain measuring system with FBG base on the latter demodulation method and the related software are designed and developed. The whole system is made up of wide-band source, FBG, transient strain demodulation interferometer, transient strain photoelectric controller and computer.The system is calibrated with the cantilever experiments and the result shows that the range of strain of the system is±3500μεand the minimum detectable relative strain is 0.69%. And through the launching pipe experiment, it proves that the system has a good stability and can complete the real-time measurement of transient strain well.