含有光纤光栅的萨尼亚克环的透射特性分析

详细分析了由光纤光栅和萨尼亚克（Sagnac)环构成的透射滤波器的特性,给出了在均匀光纤光栅的情况下,该滤波器透过率的解析公式,结果表明该滤波器的透射光谱是余弦函数调制后的光纤光栅反射光谱,当光纤光栅是“强”耦合时,该滤波器可以构成多通带滤波器,而当纤光栅为“弱”耦合时,该滤波器可以构成单通带滤波器,这些滤波器可应用于现代光纤通信系统中。     

光纤传输过程中的色散特性

基于光纤传输对于光纤通讯技术的重要意义,数值模拟光纤传输过程中的色散关系,得到随着光纤长度的增加,光纤传输中比特率减小,当入射波长为1.28μm时,光纤色散为0ps·nm<'-1>km<'-1>,研究结论为光纤传输器件设计提供理论依据.     

在非线性条件下光纤传输特性的数值分析

采用有限差分法数值求解考虑了非线性系数后的标量波动方程，发现若令两次的ｎｗ迭代差值小于１０－９以及对光纤径向迭代做足够多的分层时，则有限差分法具有较高的精确度，并且适用于任意折射率剖面光纤。同时通过计算发现在非线性条件下，光纤的色散值比线性条件下的偏大，即零色散点向短波长方向移动，而且发现波长越短，非线性效果越明显。最后给出了普通单模光纤中在非线性条件下的模拟结果。     

Transmission Characteristics of Several Kinds of Filters for WDM Optical Networking

１ＩｎｔｒｏｄｕｃｔｉｏｎＷａｖｅｌｅｎｇｔｈｄｉｖｉｓｉｏｎｍｕｌｔｉｐｌｅｘｉｎｇ（ＷＤＭ）ｉｓａｃｏｓｔｅｆｅｃｔｉｖｅｗａｙｔｏｍａｋｅｆｕｌｕｓｅｏｆｔｈｅｂｒｏａｄｂａｎｄｗｉｄｔｈｏｆｔｈｅｏｐｔｉｃａｌｆｉｂｅｒｗｈｅｎｔｈｅｔｒ...     

光子晶体光纤的传输模式特性

基于平面波展开法,数值模拟高光子晶体光纤传输的几种模式,介绍光子晶体光纤的应用及发展.结论为光子晶体光纤通信的器件设计提供参考.     

Numerical Simulation for FWM Power Evaluation in Optical Fiber Transmission Systems

In order to realize reliable and fast simulation of FWM power evaluation, USSD (Uniform Step-Size Distribution) method is modified and its corresponding simulation results of FWM efficiency and computational time are presented.     

腐蚀后的新型长周期光纤光栅特性研究

报道了高频CO2激光脉冲写入的长周期光纤光栅的腐蚀特性,即LPFG的谐振波长随腐蚀时间的变化线性地向长波方向漂移,而其谐振峰幅值变化却很小.首次对腐蚀后的长周期光纤光栅的基础特性进行了研究,发现其温度、应变、扭曲特性都未发生改变,而弯曲灵敏度比未腐蚀时的要小.从而得出了可用腐蚀来调整长周期光纤光栅谐振波长而不改变其特性的结论.     

Polymer Optical Fiber Photosensitivities and Highly Tunable Fiber Gratings

In this paper, recent progress in the investigation of photosensitivities of polymer optical fibers and the development of polymer optical fiber grating is reported. Photosensitivities in various polymer fibers, including doped and undoped, multimode and single-mode polymer fibers, have been experimentally characterized and evaluated for fiber grating application. In particular, the wavelength dependence of material absorption and photosensitivity has been found essential to the fabrication of polymer optical fiber grating. Based on the results of photosensitivity research, polymer optical fiber gratings have been successfully fabricated. More importantly, polymer optical fiber grating has been demonstrated highly tunable, with a tuning range more than 70 nm. The unique feature of high tunability in polymer optical fiber grating has great potential in various applications including optical fiber WDM systems and fiber sensor systems. Several important issues that remain to be investigated will also be discussed.     

Polymer Optical Fiber Photosensitivities and Highly Tunable Fiber Gratings

In this paper, recent progress in the investigation of photosensitivities of polymer optical fibers and the development of polymer optical fiber grating is reported. Photosensitivities in various polymer fibers, including doped and undoped, multimode and single-mode polymer fibers, have been experimentally characterized and evaluated for fiber grating application. In particular, the wavelength dependence of material absorption and photosensitivity has been found essential to the fabrication of polymer optical fiber grating. Based on the results of photosensitivity research, polymer optical fiber gratings have been successfully fabricated. More importantly, polymer optical fiber grating has been demonstrated highly tunable, with a tuning range more than 70 nm. The unique feature of high tunability in polymer optical fiber grating has great potential in various applications including optical fiber WDM systems and fiber sensor systems. Several important issues that remain to be investigated will also be discussed.     

光纤耦合模理论及其在光纤布拉格光栅上的应用

将正确的光纤中的正交关系应用于微扰耦合模理论得到了光纤中的微扰耦合模方程；并将其应用于光纤布拉格光栅，得到了一种新耦合模方程。该方程中作为标志性特性的耦合系数与其它理论中的耦合系数都不相同。讨论了方程的解，得到了峰值反射率与布拉格波长、光栅长度之间的简单关系式。用光纤布拉格光栅进行了实验，理论和实验结果符合得很好。     

横向衍射技术测量光纤光栅的特性

提出了一种用Ｈｅ－Ｎｅ激光侧面照射光纤光栅，从另一侧探测光栅的布拉格衍射效率来测量光纤光栅光谱特性的技术，并用该技术测量了光栅的折射率变化的分布。     

长周期光纤光栅透射谱计算方法的比较与分析

长周期光纤光栅透射谱的求解方法有多种,本文以耦合模理论为基础,对常用的积分法、公式法、传输矩阵法求解长周期光纤光栅的透射谱进行比较与分析,指出这三种求解方法各自的特点和适用条件.积分法可在较宽波长范围内直接得到多个模式透射谱的精确解,但求解过程繁琐,运算量大;公式法虽然在表述和计算上较为方便,但只能在较小波长范围内直接求解单个模式的透射谱;传输矩阵法求解过程简便、准确度高、计算量相对较小,特别适合计算一些非均匀光纤光栅的透射谱.该研究为选择一种精确度高且理论和计算都较简单的计算长周期光纤光栅透射谱的方法提供理论依据.     

长周期光纤光栅透射谱计算方法的比较与分析

长周期光纤光栅透射谱的求解方法有多种,本文以耦合模理论为基础,对常用的积分法、公式法、传输矩阵法求解长周期光纤光栅的透射谱进行比较与分析,指出这三种求解方法各自的特点和适用条件.积分法可在较宽波长范围内直接得到多个模式透射谱的精确解,但求解过程繁琐,运算量大;公式法虽然在表述和计算上较为方便,但只能在较小波长范围内直接求解单个模式的透射谱;传输矩阵法求解过程简便、准确度高、计算量相对较小,特别适合计算一些非均匀光纤光栅的透射谱.该研究为选择一种精确度高且理论和计算都较简单的计算长周期光纤光栅透射谱的方法提供理论依据.     

扫描近场光学显微镜中两类光纤探针传输特性的研究

采用局域模式耦合理论，对扫描近场光学显微镜中的两类光纤探针－腐蚀锥和熔拉锥的传输特性进行了比较和分析。给出了光在探针锥中传输时耦合效率的分布情况，以及传输效率随锥长，针尖直径和光波长变化的特性。     

Numerical Analysis on Transmission Characteristics of a Bragg Grating Assisted Mismatched Fiber Coupler

Based on mode-coupled theory, a Bragg grating assisted mismatched fiber coupler is analyzed theoretically. At the same time, a detailed numerical analysis on transmission characteristics of the coupler is carried out when it considers the arcs of two fibers in the coupling region of the coupler or not, and the optimized design on the Bragg grating assisted mismatched fiber coupler for wavelength-division multiplexing/ demultiplexing is proposed.     

Numerical Analysis on Transmission Characteristics of a Bragg Grating Assisted Mismatched Fiber Coupler

l IntroductionWavelength-division multiplexing (~) technology is an imPOrtant approach tosatisfy substantial increase of telecommunication network capacity. As one Of keytechnologies used in WDM networks, much progress has been made for wavelengthdivision multipl exing/ demul tip lexing technology thes e years. Based on perfect spectrumcharacteristics of fiber Bragg gratingS and fiber coUPlers, many approaches have beenproPOSed for wavelength-division multiplexing/ de multi pl eXing in a…     

熊猫光纤光栅压力传感特性研究

采用有限元法建立了熊猫光纤光栅的压力传感模型,分析了压力变化所导致的内部应力分布.结果表明,熊猫光纤光栅双峰间距随着压力增加而增大,其快轴方向的压力灵敏度系数为-4.08 pm/MPa,其绝对值大于慢轴方向-3.5 pm/MPa.理论分析和实验测量了几何结构对压力传感特性的影响规律,结果表明,熊猫光纤光栅压力灵敏度系数与猫眼半径距离比的平方成线性关系.对比实验结果表明,无法通过测量熊猫光纤光栅双峰间距的方案实现对温度不敏感的压力传感测量.     

纳米孔隙聚合物光学薄膜透过率谱线的数值计算

用时域有限差分（Finite Difference Time Domain－FDTD）算法模拟了光从真空垂直入射到表面覆盖有一层纳米孔隙聚合物薄膜的玻璃介质,得到了在不同波长下的纳米孔隙薄膜的透过率谱线.将FDTD模拟结果的透过率谱线与理论谱线相对照,估算出了该薄膜的等效折射率.我们分别模拟了孔隙率为5%、10%、15%、20%和30%的薄膜,得到了它们的透过率谱线,而且利用这些谱线得到了它们不同的等效折射率值.文末给出了只有两层薄膜构成的纳米孔隙宽带增透薄膜的结构,而且利用FDTD算法模拟了光经过这种增透膜入射到玻璃介质的过程,结果显示这种增透膜在可见光波长范围的透过率高达99.5%.     

Simultaneous Strain and Temperature Measurement with Optical Fiber Gratings: Error Analysis

Many schemes designed to simultaneously measure strain and temperature with optical fiber grating sensors have been reported in recent years. In this paper, the influence of systematic errors associated with the measurement process is analyzed and the error formulas are derived. The results are applied to a range of techniques that are of current interest in the literature. The performance of these schemes is contrasted with respect to the influence of wavelength measurement error and sensitivity matrix error.     

Simultaneous Strain and Temperature Measurement with Optical Fiber Gratings: Error Analysis

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