相移光纤光栅滤波特性研究及其传感应用

发布时间：2018-01-21 19:28

本文关键词： 光纤光栅相移滤波传感　出处：《广西师范大学》2015年硕士论文　论文类型：学位论文

【摘要】：二十一世纪以来,光纤光栅的迅速发展给通信领域带来了翻天覆地的变化。随着实际生产要求的严格化,光纤光栅在某些方面的应用也遇到瓶颈。为了克服在实用化上的障碍,通过改变结构和参数,研究人员探究了不同形态下光纤光栅的特性和应用。对光纤中纤芯折射率进行周期性调制,可以在光纤中形成特定的光栅结构。利用光栅对入射光的反射和透射原理,使得光栅的引入给光纤带来了对信号检测和识别的功能。光纤光栅的问世,加快了光纤在各个领域的发展。以光纤光栅为主要元件的器件,基本具有抵抗电磁干扰、抗腐蚀性、电绝缘、高灵敏度以及低成本的优点。光栅刻在光纤内部,可以极大的降低与光纤之间的耦合损耗和对信号光的衰减。根据在光纤中引入光栅的周期长短,光纤光栅分为周期较短的光纤布拉格光栅和长周期光纤光栅。相移光纤光栅是一种基本的光纤布拉格光栅。通过在光栅中某处引入相移,使原先的光纤布拉格光栅反射谱的反射峰中心打开一个窗口,进而产生了与长周期光纤光栅相似的透射性质。通过了解光纤布拉格光栅,利用多层膜法分析相移光纤光栅的滤波原理,得出其传输矩阵,并能进一步了解其色散和时延特性。相移光纤光栅的制作对其应用有十分重要的影响。制作过程中,相移的引入是关键之处。本文中,在光纤布拉格光栅制作的基础上,通过直接引入相移等方法制作相移光纤光栅。相移光纤光栅的特点是光栅中引入相移,但是随着引入相移的个数、位置以及大小的不同,相移光纤光栅表现出不同的特点。文中通过利用MATLAB和OptiGrating软件编程,对光栅参数对相移光纤光栅滤波特性的影响做出了详细的分析。结果发现：1.光栅的多个参数均对滤波特性产生影响,而且透射窗口的位置随耦合系数和光栅长度近似呈线性变化：2.对于双相移光纤光栅,其传输谱随着相移点位置由内向外的移动而向内塌缩；3.随着相移点的增多,中心透射窗口附近的反射峰反射率迅速下降。通过适当选取相移点的位置,可以形成多透射窗口和超宽矩形透射窗口。在光纤布拉格光栅中引入相移,所得到的透射窗口具有比光纤布拉格光栅反射峰更窄的特点。通过对相移光纤光栅进行切趾,可以消除旁瓣对光栅滤波的影响,提高精度和信号质量。相移光纤光栅具有高灵敏度,高精度、高分辨率和低损耗、低成本的特性,可应用于传感和解调系统中,实现对温度、应变和折射率等外界因素的探测。相移光纤光栅具有比普通光纤布拉格光栅更优良的滤波特性,而光纤布拉格光栅的成功应用,使得相移光纤光栅在许多方面可作为系统元件代替光纤布拉格光栅而使用,实现对外界信号的实时测量。
[Abstract]:Since 21th century, the rapid development of fiber Bragg gratings (FBG) has brought tremendous changes to the field of communication. Fiber Bragg gratings (FBG) in some applications also encounter bottlenecks. In order to overcome the practical obstacles, by changing the structure and parameters. The researchers explored the properties and applications of fiber gratings in different shapes and periodically modulated the refractive index of fiber cores. Using the principle of reflection and transmission of the incident light, the introduction of grating has brought the function of signal detection and recognition to the fiber. Fiber Bragg grating (FBG) as the main component has the advantages of resistance to electromagnetic interference, corrosion resistance, electrical insulation, high sensitivity and low cost. The coupling loss between the fiber and the attenuation of the signal light can be greatly reduced according to the period of the grating introduced in the fiber. Fiber Bragg gratings are divided into short period fiber Bragg gratings and long period fiber gratings. Phase shifted fiber grating is a basic fiber Bragg grating. By opening a window at the center of the reflection peak of the original fiber Bragg grating, the transmission property similar to that of the long-period fiber Bragg grating is obtained. The filtering principle of phase-shifted fiber grating is analyzed by multilayer membrane method, and its transmission matrix is obtained. And can further understand its dispersion and delay characteristics. The fabrication of phase-shifted fiber grating has a very important impact on its application. In the fabrication process, the introduction of phase shift is the key. Based on the fabrication of fiber Bragg gratings, phase-shifted fiber gratings are fabricated by introducing phase shift directly. The characteristic of phase-shifted fiber gratings is the introduction of phase-shift in the grating, but with the number of phase shifts introduced. The phase shifted fiber gratings show different characteristics with different position and size. In this paper, we use MATLAB and OptiGrating software to program. The effects of grating parameters on the filtering characteristics of phase-shifted fiber gratings are analyzed in detail. The results show that several parameters of the grating have an effect on the filtering characteristics. The position of the transmission window changes linearly with the coupling coefficient and the grating length. For the double-phase shifted fiber grating, the transmission spectrum collapses with the position of the phase shift point from the inside to the outside. 3. With the increase of phase shift points, the reflectivity of the reflection peak near the central transmission window decreases rapidly, and the position of the phase shift point is properly selected. The multi-transmission window and the ultra-wide rectangular transmission window can be formed, and the phase shift is introduced into the fiber Bragg grating. The transmission window is narrower than fiber Bragg grating reflection peak. The influence of sidelobe on grating filter can be eliminated by apodization of phase-shifted fiber grating. High sensitivity, high precision, high resolution, low loss and low cost, phase-shifted fiber grating can be used in sensing and demodulation system to achieve temperature. Detection of external factors such as strain and refractive index. Phase shifted fiber gratings have better filtering characteristics than ordinary fiber Bragg gratings, and fiber Bragg gratings are successfully applied. The phase-shifted fiber grating can be used as a system element instead of fiber Bragg grating in many aspects to realize the real-time measurement of external signals.
【学位授予单位】：广西师范大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN253

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