A Study On Fourier Transformation Demodulating Theory And Simulation Verification Of The Gap Of Fiber Bragg Grating Fabry-Perot Sensor

The end of the20th century, the Fiber Bragg Grating Fabry-Perot Sensor had been found by M.G.Shlyagin et al. The Fiber Bragg Grating Fabry-Perot Sensor and its cavity demodulation method have draw much attentions. In this paper, we introduced the status of Fiber Bragg Grating Fabry-Perot Sensor and its research significance, presented the methods of fabricated and classification of Fiber Bragg Grating, and described the characteristic of Fiber Bragg Grating briefly. At the same time, using the theory of the coupled-mode and transfer matrix respectively to analyze the intensity spectrum of the uniform Fiber Bragg Grating and the phase spectrum of the higher and lower reflectivity of the uniform Fiber Bragg Grating.On the basis, we presented the application of the uniform Fiber Bragg Grating in each area and analyzed the difference between the nature of the ordinary Fabry-Perot and Fiber Bragg Grating Fabry-Perot in detail. Based on the research works above, considering the disadvantages of its, this text proposed a phase demodulation method of Fourier transform which is based on the actual gauss light source, maked a detailed theoretical derivation on its demodulation theory.Furthermore, we presnted the concrete implementation algorithm and simulation testify. The results showed that the cavity length demodulation accuracy of this demodulation method within98.85%-99.995%range, and the average accuracy can reach99.55%. The relative error between the actual cavity length and demodulation cavity length within0.005%-1.15%,and the average relative error can be up to0.4508%.Thus, this phase demodulation method has a higher precision measurement, it not only overcomes the disadvantages of the existing demodulation method that must use tunable laser, and reduces the cost, but also can effectively demodulation the cavity information of Fiber Bragg Grating Fabry-Perot Sensor.