高速光通信系统中偏振效应若干问题的研究
文献类型：学位论文
| 作者 | 周赢武 |
| 学位类别 | 博士 |
| 答辩日期 | 2004 |
| 授予单位 | 中国科学院上海光学精密机械研究所 |
| 导师 | 方祖捷 |
| 关键词 | 偏振模色散 偏振相关损耗 偏振度 光纤光栅 |
| 其他题名 | Studies on Polarization Effects in High Speed Optical Fiber Transmission Systems |
| 中文摘要 | 人们对信息量的需求导致光纤通信技术得到快速的发展，光纤通信系统的单信道速率从10Gbit/s正在向40Gbit/S迈进；在波分复用系统中，单纤复用波长向数百个波长甚至更多发展。高速率、大容量的光纤通信系统已经在全球通信网络系统中起着主要的和骨干的作用。光纤的偏振模色散和偏振相关损耗成为限制在高速光通信系统发展的关键因素，偏振模色散和偏振相关损耗会造成高速光通信系统中传输的信号脉冲发生畸变，引起信号之间的码间干扰，使系统信噪比，增加误码率。本文对高速光通信系统的偏振效应若干问题进行了研究，主要内容包括以下几个方面：论文首先利用光纤通信系统的Jones矩阵模型，得到了输出光脉冲Stokes矢量的表达式，分析和计算了输出脉冲的偏振度特性。结果表明，输出信号的偏振度随着入射偏振态的变化而变化，在主偏振态位置上达到极大；同时，随着偏振模色散幅度的增大而变小。输出信号的偏振度还随着信号惆啾系数绝对值的增大而减小，但与惆啾系数的符号无关。在同时考虑偏振模色散及偏振相关损耗情况下，分别通过理论和蒙特一卡洛方法研究了光传输链路的输出信号偏振态相关函数。首先，从理论上得到了光传输链路的输出信号偏振态相关函数的解析表达式，而后，利用蒙特一卡洛方法进行了模拟研究。模拟的结果和解析理论能很好地吻合。研究的结果表明：随着传输链路偏振相关损耗的增大，输出偏振态的方向随频率的变化增快；而另一方面，随着光传输链路的偏振模色散的增大，输出偏振态的方向随频率的变化也增快。利用输出信号偏振态相关函数的解析表达式，研究了偏振模色散及偏振相关损耗共同作用下，偏振复用系统的特性，结果表明：当系统同时受到偏振模色散及偏振相关损耗共同作用时，其性能比只有偏振模色散的系统的更差。偏振模色散模拟器是进行偏振模色散实验研究的重要器件。论文从光纤的琼斯矩阵模型出发，利用蒙特一卡洛方法对偏振模色散模拟器的统计特性进行了研究。研究的结果表明随着组成模拟器的保偏光纤的段数增加，一阶和二阶偏振模色散的统计分布越接近于理论拟合曲线。比较了两种不同的模拟器的组成方法，得到的结果将对模拟器的设计具有实际的指导作用。接着研究了偏振相关损耗对偏振模色散模拟器的群时延差及两个主偏振态夹角统计分布的影响。结果表明：偏振相关损耗对模拟器两个主偏振态夹角分布的影响比对其群时延差的统计分布的影响来得严重。论文研究了线性惆啾光纤光栅的时延特性，在此基础上设计了一种新型的基于线性惆啾光纤光栅的偏振模色散补偿器。该补偿器的时延器由一根经过预曝光处理后写入的线性惆啾光纤光栅和一根常规的线性惆啾光纤光栅所组成。该偏振模色散补偿器具有易于动态调节，易于制备，成本低等优点论文讲述了在偏振模色散测量方面所作的一些基本实验。建立了固定分析仪法测试台，可以用来测量光纤或器件的偏振模色散。建立了Jones矩阵本征值测量法的测试装置，对该系统存在的测试误差、工艺要求等进行了分析。光纤光栅广泛应用于光纤通信和传感领域。论文在分析光纤光栅特性的基础上，提出利用预曝光技术使某一小段光纤的折射率变大，而后在预曝光部分和未曝光部分的交接处一次性写入光栅，即可得到具有两个透射峰的透射谱。从实验上研究了该复合结构光纤光栅在温度和应力传感上的应用。实验结果表明利用该复合结构光纤光栅可以实现温度与应变的同时测量．研究了写于熊猫光纤的长周期光栅的温度及应变响应特性，在所研究的温度和应变测量范围内，温度和应变响应曲线具有良好的线性；还研究了该熊猫光纤长周期光栅的金属化特性，结果表明，在所测量的范围内，谐振峰的波长随所加的电功率线性增加，而谐振峰损耗量的变化很小。在熊猫光纤长周期光纤光栅的温度和应变系数测量中发现，不同包层模阶次的快轴和慢轴谐振峰具有相反的行为。论文对观察到的现象给出了定性的解释。 |
| 英文摘要 | The optical fiber transmission technology has been growing rapidly driven by the demand of people for information, which is high-lighted by per-channel rate increased from 2.5Gbit/s to 40Gbit/s and higher and per-fiber channel number increased up-to several hundreds. High speed and large capacity optical fiber transmission system have played a key role in the global information networks. Polarization mode dispersion and polarization dependent loss is regarded as a limit to further growing of the optical fiber transmission technology. In 10 Gbit/s or more high-rate optical system, polarization mode dispersion and polarization dependent loss lead to the broadening of optical signal pulse which induces the inter-symbol interference, deteriorate the signal-to-noise ratio performance and increase the bit error rate. In this dissertation, some key issues of the effects of polarization mode dispersion and polarization dependent loss on the optical fiber transmission system are studied. The main research contents include: The expression of the output pulse Stokes vector is derived based on Jones matrix model proposed by A.Orlandini. The basic properties of degree of polarization of optical pulse have been investigated. It is shown that the degree of polarization of optical signals changes with polarization state of the input pulse, and reaches its maximum at the position of the Principal State of Polarization; it decreases with the magnitude of the polarization mode dispersion; And it decreases also with the initial chirping of the input signal, but with no relation with the sign of chirping coefficient. Then, the characteristics of the autocorrelation function of the output polarization states of the optical transmission links in presence of polarization mode dispersion and polarization dependent loss was investigated by theory and Monte-Carlo simulation method. An analytical expression for the autocorrelation function was obtained, and it is fit well with the result of the simulation. The results show, the bandwidth decrease with the polarization mode dispersion or polarization dependent loss increase. Based on the analytical expression for the autocorrelation function we obtain, the combined effects of polarization mode dispersion and polarization dependent loss on the polarization multiplexed scheme are investigated, and it is found that the performance of the polarization multiplexed scheme can be deteriorated more severely than the case without polarization dependent loss. The statistical characteristics of the first and second order polarization mode dispersion of a polarization mode dispersion emulator were studied based on the Jones matrix of optical fiber and Monte-Carlo method. Two kinds of PMD emulator were studied by comparison. The results will be helpful for PMD emulator design. Then the impacts of polarization dependent loss on the characteristics of polarization mode dispersion emulators were studied with Monte-Carlo simulations. The results show, only when the PDL is large, the differential of group delay distribution has an obvious deviation from Maxwellian. But the two principal state vectors seriously deviate from perpendicular, and with PDL increase the deviation becomes more serious. The characteristics of linearly chirp fiber Bragg grating are investigated. Then, a novel adjustable polarization mode dispersion compensation using linear chirp fiber Bragg grating is proposed. This polarization mode dispersion compensation technique is cost-effective and simple in designing. Some measurement experiments of polarization mode dispersion are introduced and discussed in the dissertation. Optical fiber Bragg gratings are widely used in fiber sensor field. A novel composite fiber Bragg gratings based on pre-exposure technology was proposed and studied experimentally. The experimental results show that the FBG can be used to measure temperature and strain simultaneously. The characteristics of long-period Bragg grating written on Panda fiber are presented. Both the strain and temperature responses show good linear characteristics at the strain range and temperature range investigated. The temperature-tuning characteristics of the LPG by using a thin film metal coating on the nude surface of the fiber as a heater are also demonstrated. The response curve of the LPG has good linearity with the applied electrical power, while the change of the resonant peak height is very small. It was observed that the temperature and strain responses for fast and slow axes of different cladding modes have opposite behaviors. A qualitative explanation is presented to the phenomena. |
| 语种 | 中文 |
| 源URL | [http://ir.siom.ac.cn/handle/181231/15332]  |
| 专题 | 上海光学精密机械研究所_学位论文 |
| 推荐引用方式 GB/T 7714 | 周赢武. 高速光通信系统中偏振效应若干问题的研究[D]. 中国科学院上海光学精密机械研究所. 2004. |
入库方式： OAI收割
来源：上海光学精密机械研究所
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