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基于光纤Bragg光栅(FBG)反射复振幅相移对FBG法布里-珀罗腔透射谱的影响,分析了传统耦合模理论计算均匀FBG反射复振幅相移产生误差的原因.引入折射率分布初始相位参数描述FBG折射率分布纵向的微小偏移,用真实的反透射系数代替简明形式的反透射系数,对传统耦合模理论进行了修正,增加了与折射率分布初始相位参数有关而与波长无关的相位因子.在此基础上进一步对计算非均匀FBG的传输矩阵法的相位进行了修正.修正后的快速计算结果用于FBG法布里-珀罗腔透射谱的计算,可反映折射率分布初始相位参数对透射峰波长位置的影响,与Rouard 算法及实验值均有较好的一致性.
关键词:
光纤Bragg 光栅
法布里-珀罗腔
耦合模理论 相似文献
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本文针对梯度折射率分布的透镜(以后简称梯析透镜)与光纤在折射率分布上的不同点,对用于光纤及其预制棒测量的聚焦法的原理公式,计算测量方法等进行了重要改进,从而使聚焦法可适用于梯折透镜的测量.本文通过计算机模拟计算,对原理公式及计算方法的准确性和可靠性进行了验证,并同时给出了这一测量方法的精度,最后给出了测量实例及其比较结果. 相似文献
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用透射式微分干涉法测量光纤内部折射率分布,其原理是利用旋转检偏器对测量光束进行调制,从相位分布和光程分布中计算出折射率分布。其中,从光程分布中解算出折射率分布的算法是关键。讨论了该算法的数学模型,推导了测量公式,并对算法的稳定性和误差进行了分析。利用自行研制的系统对渐变折射率分布光纤进行实测,与在NR 9200光纤测量仪上的结果进行了比较,对主要误差源进行了分析和计算机模拟。实测和模拟计算结果表明,该算法原理正确,系统稳定,测量精度优于10-3,完全可以用来测量光纤折射率分布。 相似文献
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传统有效折射率方法只能模拟具有相同空气孔大小的单包层光子晶体光纤.针对这一问题,提出了一种改进的有效折射率法,能够计算具有不同孔径的多包层光子晶体光纤的传输特性.并用此方法对三包层光子晶体光纤的基模有效折射率和色散等特性进行了数值模拟,结果与多极法模拟出的结果符合得很好.这种改进的有效折射率法拓展了传统有效折射率法的适用范围,对快速准确地分析和设计具有不同传输特性的多包层光子晶体光纤提供了理论依据.
关键词:
光子晶体光纤
多包层
有效折射率方法
色散 相似文献
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利用数字全息显微层析技术构建了光纤折射率测量的测试系统, 包括光路系统与软件系统. 以物光波的相位分布曲线为依据由CCD记录最优的数字全息图; 在优化频谱图的基础之上对全息图做频域滤波, 准确选取物光波所对应的频谱范围; 使用基于角谱理论的再现算法提取出物光波的相位分布信息, 并通过模拟全息图验证相位提取的准确性; 由单幅全息图提取的相位分布信息, 结合光纤的多层模型, 还原出光纤断层面沿直径方向的折射率分布. 以单模、多模光纤为实验样品进行了测量, 测量结果与S14折射率测量仪的测量结果吻合, 精度可达10-4. 实验对比结果表明本文方法可简单、快速、准确地测量光纤内部的折射率. 本文还对特种光纤的折射率进行了测量研究. 相似文献
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本文采用归一化数学模型描述有中心凹陷的α光纤的折射率分布,利用级数法求解第一个高次模(LP_(11))的截止特性,给出了与实际折射率分布直接对应的归一化截止频率,对单模α光纤的设计和测量分析具有一定的实际意义。 相似文献
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The refractive index profile of an axially symmetric fiber preform is determined by using the transport of intensity equation. In this method the preform is immersed in an index-matching liquid, and a collimated light beam impinges on it laterally. The intensity distributions of the transmitted light are measured on two close parallel planes inside the preform core. From the recorded intensity distributions, the deflection function is calculated by the transport of intensity equation. The refractive index profile is obtained by means of Abel inversion. Also, for comparison, the refractive index profile of the preform is measured by the focusing method and the results are in agreement with less than 3% error. 相似文献
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In graded-index polymer optical fiber (GI-POF), the refractive index profile is an important parameter in defining its bandwidth. However, direct determination of the refractive index profile of GI-POF is difficult due to its extreme thinness. In this study, the refractive index distribution of the GI-POF is indirectly determined by measuring the refractive index distribution of the GI-POF perform by applying the transverse ray tracing method to a simplified measurement system that we developed.In this system, a parallel tabular ray is irradiated transversely to a GI-POF preform. The transverse ray from the preform is then projected on a screen, and its digital image is processed to calculate the refractive index distribution. The calculation is based on a transverse ray simulation, a computer program that we developed in which the refractive index distribution of the preform is determined by comparing the displacement of the transverse ray projected on the screen with the actual measurement.The accuracy of this new measurement method is validated by comparing the refractive index distribution of a GI-POF preform with the refractive index distribution measured by the conventional method using an interferometer. We find that the refractive index distribution measured by this novel method agrees well with that measured by the conventional method. 相似文献
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This paper is devoted to the study on measurement of refractive index profile of graded-index polymer optical fiber (GI-POF) by light scattering. Using Generalized Airy theory and Debye series of an inhomogeneous cylinder, the scattering intensity distributions are obtained of Airy structure of rainbows for different refractive index profile. The results show that positions of Airy peaks depend closely on refractive index profile of GI-POF. Since each order of rainbow penetrates it to different depths, such methods could be used to provide information of the refractive index profile of GI-POF. For GI-POF with given diameter, positions of Airy peaks of rainbows are simulated as a function of refractive index profile, which can be used to inverse unknown parameters of refractive index profile. The least square method is used in inversion of refractive index profile with the given refractive index of the cladding. The results obtained agree with theoretical values with high precision. The method has the advantages of non-instructive and on-line measurement, and can be used for the measurement of other inhomogeneous droplets. 相似文献
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采用溶液 凝胶扩散共聚法成功地合成了二元体系的甲基烯酸苄酯 甲基烯酸甲酯 (BZMA MMA)层状梯度折射率板 ,折射率分布是其主要性能指标。给出了一种测量该制品折射率分布的简便实验装置和自动实现方法。该测量方法基于激光干涉的原理 ,由计算机自动跟踪干涉条纹的移动来计算梯度折射率材料的折射率分布。实验表明 ,该方法简单易行 ,具有较高的折射率测量精度 ,为科学评价自研制梯度折射率材料的性能提供了保证 相似文献
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Levy U Abashin M Ikeda K Krishnamoorthy A Cunningham J Fainman Y 《Physical review letters》2007,98(24):243901
We experimentally demonstrate for the first time the focusing of optical beams within an inhomogeneous dielectric metamaterial with space-variant polarizability, implemented by etching subwavelength structures into a Silicon slab. Light focusing is obtained by creating an artificial slab material with graded refractive index profile. The local refractive index within the slab is modulated by controlling the duty cycle of the subwavelength structures. The demonstrated metamaterial based component can be integrated with various other building blocks towards the realization of devices and systems in free space optics on a chip configuration. 相似文献
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用于高速数据通信的梯度塑料光纤 总被引:1,自引:0,他引:1
概述了梯度塑料光纤的开发历史和现状。从应用于高速数据通信的角度 ,介绍了聚甲基丙烯酸甲酯(PMMA)、全氘化和全氟化梯度塑料光纤的损耗、带宽、稳定性和寿命。详细介绍了梯度塑料光纤的损耗光谱和损耗机制 ,介绍了制作梯度塑料光纤的界面凝胶聚合技术和两种扩散法 ,分析了梯度塑料光纤的制作方法同折射率剖面和带宽的关系 ,讨论了梯度塑料光纤的稳定性同掺杂物质的关系。同时介绍了高稳定性梯度塑料光纤的研究进展及今后的发展动向 相似文献
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基于光束扫描法的光纤预制棒折射率测试仪主要适用于直径和长度在一定范围内的圆柱形样品折射率分布的测试。提出一种套管辅助法可实现更短长度、更细直径和变直径样品的折射率测试。该方法将待测样品居中放置于一个尺寸符合测试要求的圆柱形套管内,并在套管内注入折射率匹配油,使其没过待测样品后按常规步骤进行测试。对比实验结果表明,套管辅助法与直接测量法的偏差与仪器的测量误差相当。采用套管法,获得了预制棒拉丝终止后变径区不同位置折射率的径向分布,可为拉丝过程的研究提供参考。 相似文献
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迭代法重建平板光波导折射率分布 总被引:1,自引:0,他引:1
提出了一种用于重建渐变折射率平板光波导折射率分布的方法,这种方法通过数值法求解亥姆霍兹方程.从光波导的低阶模开始采用迭代法顺次对各个模式对应的“转折点”位置进行校正.并多次重复迭代以消除“转折点”外折射率分布的变化对相应模式“转折点”位置的影响。借助WKB近似原理说明了这种方法迭代过程中“转折点”坐标的收敛性。对折射率按照指数规律变化的平板光波导的折射率分布重建结果证明这种方法具有较高的精度。分析表明:这种方法克服了WKB法固有的缺陷,即忽略模式“转折点”外折射率分布对相应模式传输常鞋的影响和“转折点”处相移的不确定性,因而比逆WKB法具有更好的自洽性和精确性。 相似文献
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In this paper, finite element method (FEM) mode analyses of planar slab optical waveguide having complicated refractive index profile are presented. We try to estimate the dispersion graph, mode cut-off condition, group delay and waveguide dispersion for the case of α-power and chirped-type refractive index profile. In order to obtain the more accurate result, we have derived the higher-order polynomial, which establishes the suitable relationship between b and V for different profile of optical waveguide. On the basis of the derived polynomials, the waveguide dispersion is analyzed for different type of refractive index profile waveguide. Our study shows that the waveguide dispersion can be substantially reduced when we deployed the optical waveguide having linearly chirped-type refractive index profile. Earlier too, the arbitrary refractive index profile has been analyzed but to the best of our knowledge chirped-type refractive index profile has not been analyzed till date for the case of planar slab optical waveguide. 相似文献