Characteristics And Sensing Applications Of Photonic Crystal Fiber Grating

Photonic crystal fiber grating is produced by the combination of fiber grating and photonic crystal fiber. The photon passive device is one of the most rapid development components in recent years. Because its excellent structure characteristics compared with traditional optical fiber grat ing, photonic crystal fiber grating has a lot of advantages in sensing field. In the case of different structural parameters, the effective refractive index is change. When temperature or stress is changed, their sensing characteristic is changed. So it is used widely in the field of sensing.The paper mainly designs a kind of nine sides grating structure. In different conditions of structural parameters and external influences, the transmission spectrum characteristics and sensing characteristics are studied.In the first chapter, the development and types of photonic crystal fiber are introduced, and the general situation and characteristics of fiber grating are also summarized.In the second chapter, the four common methods of photonic crystal fiber grating are introduced in detail, which are coupled mode theory, transfer matrix method, Fourier transform method and finite element method. Secondly, in terms of practical application, this paper introduces five different kinds of tangent function. In this paper, the experimental simulation method is the transfer matrix method.In the third chapter, the paper analyzes relationship of wavelength and spectral properties on different air hole number, different air ratio and other parameters. The results show that an increase of the air hole layers can reduce the leakage of the spectral energy, but the resonance wavelength shift and the resonance peak intensity are not obvious. In addition to air holes, the spectral characteristics of the transmission spectrum are affected by the change of the grating parameters.In the fourth chapter, based on the fiber Bragg grating sensing theory, the change of the sensing characteristics of this PCFBG in temperature and stress is discussed. The results from the simulation show that as the temperature rises, the phenomenon of the fiber grating resonance wavelength shift to longer wavelength direction is more obvious, however, as the stress increases, the drift amount of the resonance wavelength towards long wavelength is very small. At the same time, the change of the sensing sensitivity under the condition of different duty ratio and different air hole layers is analyzed. It is found that the change of the grating structure has little effect on the sensitivity.The fifth chapter summarizes the research of the nine side shaped photonic crystal fiber Bragg grating. Meanwhile, the future development prospects of photonic crystal fiber grating are also discussed.