扭转光纤光栅的光学特性及传感特性的研究

发布时间：2018-07-18 21:14

【摘要】：光纤光栅在光通信、光传感、光测量等方面都有重要应用,尤其在航空航天和桥梁监测等结构健康监测领域得到了广泛应用。然而,传统的光纤光栅无法在强紫外、强辐射以及高温环境下长期工作,原因是光栅结构会受到影响甚至破坏。针对这一问题,近年来一种新型的螺旋型手征光纤光栅(Chiral Fiber Gratings CFG)逐渐受到了研究人员的重视。本论文的工作内容围绕着扭转光纤光栅而展开,主要包括两个方面,一是研究光纤在生产过程中,熔融条件下,高速扭转截面非圆对称光纤制作而成的螺旋型手征光纤光栅,其光谱特性及传感应用。二是讨论了生产过程中未扭转的普通光栅在扭转传感器中的应用。首先,阐述光纤光栅的工作原理,根据耦合模理论,详细分析了双螺旋型长周期手征光纤光栅(Chiral Long Period Fiber Gratings CLPG)的光谱特性和耦合特性,模拟了相应的透射谱,并实验测试了该光栅的透射谱。在此基础上,利用相位匹配条件,计算了特定谐振波长所对应的扭转周期及扭转率,模拟了相应的透射谱,并讨论了光栅的设计参数对透射谱的影响。分析了双螺旋型CLPG的应变传感特性,研究表明其传感特性与传统的长周期光纤光栅类似,谐振波长受应变变化会发生偏移,并且波长的偏移量与应变呈线性关系,灵敏度为0.828pm/με。宓同时,分析了弹光系数对透射谱和灵敏度的影响。根据琼斯矩阵和传输矩阵法,理论分析和数值模拟扭转FBG(光纤布拉格光栅Fiber Bragg Gratings)与PDL(偏振相关损耗Polarization Dependent Loss)响应的关系,通过测量PDL幅值变化,可实现不受应变和温度干扰,扭转传感的测量。此外,这可以同时获得扭转方向和扭转角两个量,实验结果和数值模拟较符,扭转灵敏度为0.955 dB/rad。
[Abstract]:Fiber Bragg grating (FBG) has important applications in optical communication, optical sensing and optical measurement, especially in the field of structural health monitoring such as aerospace and bridge monitoring. However, the traditional fiber gratings can not work in strong ultraviolet, strong radiation and high temperature environment for a long time, because the structure of the grating will be affected or even destroyed. In order to solve this problem, a new type of chiral fiber grating (chiral fiber Gratings CFG) has been paid more and more attention by researchers in recent years. The work of this thesis is focused on torsional fiber gratings, including two aspects. One is to study the helical chiral fiber gratings fabricated by high-speed torsional non-circular symmetric fiber in the production process and melting condition. Its spectral characteristics and sensing applications. Secondly, the application of untwisted grating in torsion sensor is discussed. Firstly, the principle of fiber Bragg grating is described. Based on the coupled mode theory, the spectral and coupling characteristics of the chiral long period fiber Gratings CLPG are analyzed in detail, and the corresponding transmission spectra are simulated. The transmission spectrum of the grating is measured experimentally. On this basis, the torsion period and torsion rate corresponding to a particular resonant wavelength are calculated by using phase matching conditions, the corresponding transmission spectra are simulated, and the influence of the design parameters of the grating on the transmission spectrum is discussed. The strain sensing characteristics of double helical fiber gratings are analyzed. It is shown that the sensing characteristics are similar to those of the traditional long period fiber gratings, and the resonant wavelength will be offset by strain variation, and the deviation of the wavelength is linearly related to the strain, and the sensitivity is 0.828pm/ 渭蔚. At the same time, the influence of elastic-optical coefficient on transmission spectrum and sensitivity is analyzed. According to Jones matrix and transfer matrix method, the relationship between fiber Bragg grating (FBG) and PDL (polarization dependent loss) response is analyzed and numerically simulated. The measurement of a torsion sensor. In addition, the torsional direction and torsion angle can be obtained simultaneously. The experimental results are compared with the numerical simulation. The torsional sensitivity is 0.955 dB / Rrad.
【学位授予单位】：南京师范大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN253

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