1、 光纤光栅论文：特殊光纤光栅滤波器的理论研究及应用【中文摘要】作为一种光纤型滤波器件,光纤光栅以其与光纤完全兼容、反射特性好、附加损耗小、体积小、成本低,对外界温度、应力、应变的变化具有较好的响应特性等优点在光纤通信与光纤传感领域得到了快速的发展与应用,并且随着“三网融合”及全光网络的发展将会发挥越来越重要的作用。本文首先以耦合模理论、传输矩阵法及离散层析算法为根本方法,研究分析了取样光纤光栅、相移光纤光栅、三角光谱光纤光栅、倾斜光谱光纤光栅等多种光栅的内部结构及光谱特性。并在此基础上重点对多通道的光纤光栅进行了研究取得了以下两方面的成果。(1)设计了一种刻写在高双折射光纤上的Sinc取样光纤
2、光栅,该光栅具有两套偏振方向互相垂直的不同反射波长的光谱；合理设计高双折射光纤的快慢轴折射率差,可在同样长的光敏光纤上得到两倍于普通取样光纤光栅的信道数目,提高了光纤的利用率并能降低对光纤光敏性的要求。理论研究了该型光栅的色散特性和切趾优化。结果表明：这种具有梳状反射谱的光栅在多波长偏振光纤激光器和光纤传感网络中具有极大的应用价值。(2)对重构多信道光纤光栅的离散层析算法进行了优化。在各信道加入相移的基础上,运用非线性最小二乘法对耦合系数进行高斯曲线拟合,降低了折射率调制深度的最大值且可以将剧烈变化的折射率调制深度平滑化。仿真表明,较之改进前的折射率调制最大值(0.0013),利用新算法在折射
3、率调制最大值为0.0005时成功设计了一个8信道光纤光栅,极大地降低了对光纤光敏性的要求。同时,折射率调制曲线的平滑化降低了光栅的实际刻写难度其次,文章研究了Rsoft软件GratingMOD模块在处理光纤光栅问题时的具体应用。应用该软件首先对Bragg光纤光栅以及矩形取样光纤光栅进行了仿真,又分别设计了八信道的取样光纤光栅及三角光谱光纤光栅,与MATLAB仿真结果进行了对比。GratingMOD可以正确快速的得到所需结果,从而简化了光栅的设计方法,并使的设计更形象、直观。最后,介绍了一种波长可切换的线偏振掺Yb双包层光纤激光器,利用保偏光纤布拉格光栅和高反射率的啁啾光纤光栅构成激光谐振腔,以
4、单模保偏双包层掺Yb光纤为增益介质,通过调节腔内的偏振控制器的旋转角度实现了激光分别在两个单波长之间的切换。输出激光的波长在1070.08nm和1070.39nm、功率为1W、消光比为48dB斜率效率为52%, FWHM为0.022nm；用格兰汤姆逊棱镜研究了该激光的偏振特性。【英文摘要】Because of the excellent characteristics, such as natural compatibility with fiber, fine reflectivity performance, low insertion loss, small volume, low co
5、st and high sensitivity to the changes of environmental temperature, stress and strain, etc, fiber gratings have been and will be used in fiber communication and fiber sensing domain extensively. With the rapid development of Tri-Networks Integration and All-Optical Network, fiber grating will play
6、a more and more important role in these areas.Firstly, this article studies several special spectral fiber gratings such as sampled fiber Bragg grating, phase-shifted fiber Bragg grating, triangular fiber Bragg grating, and tiled fiber Bragg grating using the couple mode theory, transfer matrix meth
7、od, and discrete layer peeling. Among of them, the multi-channel grating filters are designed and analyzed in a focused manner and two main results are listed as following.(1) Design a new kind of Sinc-sampled fiber Bragg grating which is fabricated in the high birefringence fiber. The sampled grati
8、ng has two sets of reflection spectra along two perpendicularly polarization directions. The gratings channel number can be doubled by approximately designing the refractive index difference between the fast and slow axes of the fiber, which enhances the utilization ratio and reduces the claim for p
9、hotosensitivity of the fiber. The group delay characteristics are theoretically studied and side-lobes are depressed by apodization technique in order to get optimized spectra. The results show that the comb-like spectra of the grating enable it have promising applications in both multi-wavelength p
10、olarized fiber laser and fiber sensing network.(2) The discrete layer-peeling method for designing multi-channel fiber Bragg grating is optimized. In the new method, after inserting different phase changes at different channels, the coupling coefficients is then fitted by Gaussian function to get a
11、lower and more smooth refractive index modulation. The simulation results show that a 8-channel fiber Bragg grating is successfully designed by using the new method with the maximum refractive index modulation of 0.0005, much lower than that of traditional DLP method (0.0013), which decreases the re
12、quirement of fibers optical sensitivity. Meanwhile, the difficulty of inscribing a fiber grating is reduced by smoothing the refractive index modulation. Secondly, the application of GratingMOD module of Rsoft software in analyzing and synthesizing fiber gratings is introduced. By using the GratingM
13、OD, fiber Bragg grating, rectangular-sampled fiber grating, 8-channel sampled fiber grating and triangular fiber grating are simulated. The relevant results are compared to those by the MATLAB method. And the results show that the software can deal with the grating filters design problems convenient
14、ly and rapidly.Lastly, a wavelength switchable linear polarization Yb-doped double clad fiber laser is proposed, in which the resonant cavity is composed of a polarization-maintaining fiber Bragg grating as the lower reflective mirror and a chirped fiber grating as the higher reflective mirror. A 8-
15、meter single mode polarization maintaining double clad Yb-doped fiber is used as the gain material. Two lasting wavelength of laser at 1070.08 nm and 1070.39 nm are realized and the two wavelength can be switched by changing the polarization state of the cavity. The other characteristics of the lase
16、r, such as power of 1 W, extinction ratio of 48 dB, slope efficiency of 52% and FWHM of 0.022 nm, are tested. The polarization characteristics are studied by a Glan-Thompson-type prism polarizers.【关键词】光纤光栅 耦合模 离散层析 光栅分析模块 掺镱光纤激光器【英文关键词】fiber Bragg grating coupled-mode theory discrete layer peeling G
17、ratingMOD Yb-doped fiber laser【目录】特殊光纤光栅滤波器的理论研究及应用摘要8-10ABSTRACT10-11符号说明12-13第一章 概论13-201.1 光纤光栅的发展13-141.2 掺锗光纤的光敏性14-151.3 光纤光栅的分类15-161.4 光纤光栅写入方法16-191.4.1 光纤Bragg光栅16-171.4.2 啁啾光纤光栅17-181.4.3 取样光纤光栅181.4.4 相移光纤光栅181.4.5 切趾光纤光栅18-191.5 本章小结19-20第二章 光纤光栅研究理论20-302.1 光纤光栅理论模型20-212.2 耦合模理论21-252
18、.2.1 基本理论21-242.2.2 均匀Bragg光纤光栅光谱分析24-252.3 传输矩阵法25-282.3.1 基本理论25-272.3.2 啁啾光纤光栅光谱分析27-282.4 光纤光栅的切趾分析28-292.5 本章小结29-30第三章 特殊光纤光栅分析30-403.1 矩形取样光纤光栅30-343.1.1 矩形取样光纤光栅原理30-323.1.2 矩形取样光纤光栅特性32-343.2 Sinc取样光纤光栅34-353.3 刻写在高双折射光纤上的Sinc取样光纤光栅35-373.4 相移光纤光栅37-393.5 本章小结39-40第四章 离散层析算法应用及改进40-514.1 DL
19、P算法41-444.2 DLP算法重构倾斜光谱光纤光栅44-464.3 DLP算法重构多信道光纤光栅46-474.3.1 基本方法464.3.2 耦合系数对多信道光纤光栅重构谱的影响46-474.4 MATLAB拟合工具箱47-484.5 对多信道光纤光栅重构的改进DLP算法48-504.6 本章小结50-51第五章 GratingMOD在光纤光栅模拟中的应用51-585.1 GratingMOD简介51-525.2 GratingMOD分析光纤光栅52-545.2.1 光纤Bragg光栅仿真设计52-535.2.2 矩形取样光栅53-545.3 GragtingMOD重构光纤光栅54-565.3.1 八信道光栅滤波器54-555.3.2 三角光谱光纤光栅滤波器55-565.4 啁啾及切趾功能56-575.5 本章小结57-58第六章 双折射啁啾光纤光栅在掺镱光纤激光器的应用58-646.1 光纤激光器简介58-596.2 双波长可切换掺镱双包层光纤激光器59-636.2.1 掺镱双包层光纤激光器59-606.2.2 实验原理60-616.2.3 实验结果及讨论61-636.3 本章小结63-64第七章 总结64-66参考文献66-71致谢71-72攻读硕士学位期间发表的论文72-73学位论文评阅及答辩情况表73
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