光纤和光缆的偏振模色散系数研究

综述了偏振模色散的概念、偏振模色散对光传输系统的影响、系统对单模光纤偏振模色散系数的要求,以及获得小的偏振模色散光纤和光缆的方法.     

A fully polarimetric optical time-domain reflectometer

We report the implementation of the first fully polarization sensitive optical time domain reflectometer (POTDR). This nondestructive measurement technique, requiring access to one fiber end only, enables the determination of both the linear and twist induced circular birefringence distribution along the fiber. This information, combined with a knowledge of the mode coupling length, enables the evaluation of the polarization mode dispersion (PMD) properties of fibers and optical cables exhibiting both types of birefringence, as well as identifying fiber sections with and without twist. The POTDR, which has a spatial resolution of 0.3 m, could also be used for monitoring the birefringence properties of fibers at the manufacturing stage, leading to optimization of fabrication techniques to minimize PMD     

骨架式光纤带光缆用于FTTH的解决方案

将骨架式光纤带光缆用于FTTH的解决方案是将接人用的光纤带光缆中的光纤从机房连到若干交接箱,再接入各住宅单元,并根据住宅单元的不同结构选择所需接入的骨架式光纤带光缆.通过在骨架式光纤带光缆上开启若干分离窗口就可直接抽出需要接入住户的光纤带,而不必按通常的方式将光缆剪断,因无需接续且只需极少量的光缆,加上骨架式光纤带光缆无油膏填充的特点,极大地简化和方便了FTTH的设计和施工.     

Design and performance of ultra-high-density optical fiber cable with rollable optical fiber ribbons

This paper proposes a novel ultra-high-density optical fiber cable that employs rollable optical fiber ribbons. The cable has great advantages in terms of cable weight and diameter, and fiber splicing workability. Moreover, it will be easy to install in a small space in underground ducts and on residential and business premises. The structural design of the rollable optical fiber ribbon is evaluated theoretically and experimentally, and an optimum adhesion pitch P in the longitudinal direction is obtained. In addition, we examined the performance of ultra-high-density cables with a small diameter that employ rollable optical fiber ribbons and bending-loss insensitive optical fibers. The transmission, mechanical and mid-span access performance of these cables was confirmed to be excellent.     

Large polarization mode dispersion in fiber optic cables

The recently observed difference in polarization mode dispersion (PMD) between spooled and cabled single-mode optical fibers is investigated experimentally. To discriminate between a large polarization mode-coupling length or a large birefringence as a cause of high PMD, both parameters are measured. The results show a factor of 50 difference between the mode-coupling lengths of spooled and cabled fibers, which accounts for the larger PMD's of cabled fibers. It is suggested that cables with a loose tube design especially suffer from large polarization mode-coupling lengths. Internal stress is shown to be the dominant source of birefringence in standard telecommunication fibers by observing the shift of the PMD spectrum over a wide wavelength interval as a function of temperature     

色散管理传输系统中克尔效应对偏振模色散的补偿研究

光纤的随机双折射效应可导致脉冲无规展宽即偏振模色散(PMD)。在零路径色散管理孤子传输系统中，二阶色散和三阶色散效应均被完全补偿，克尔效应成为一种有害因素会使脉冲变窄，但是当光纤的随机双折射被考虑时，克尔效应正好与PMD相互抵消，使光脉冲准稳定传输，不同的光纤偏振模色散参数分别对应不同的最佳系统功率。此外，如果考虑不同偏振方向的损耗差异，则即使在最佳匹配条件下，微小的偏振损耗差异也可产生很大的脉宽波动。因此，偏振相关损耗是影响脉冲传输质量的相当重要的因素，不论在理论计算还是在工程设计中都应当认真考虑。     

中国光纤通信技术的研究、应用和发展

主要从光纤光缆、光器件与组件、光传输设备与系统、光网络建设等方面论述光纤通信技术在我国的研究、应用发展历程，并对我国光纤通信技术的未来发展进行展望。     

光系统领域的发展——介绍上海光纤报告会

自１９９０年到２１世纪初，通信对带宽的需求呈指数增长；传输技术正向高比特率和密集波分复用（ＤＭＤＭ）发展；正在研究以统计法确定偏振模色散（ＰＭＤ）的规范；对于多芯数光缆的需求增加使得光纤带光缆前景广阔；用具有正色散的真波光纤与负色散的真波光纤相间连接的系统可不需色散补偿，最适于陆地长途干线应用。增加光纤的有效面积可克服非线性效应。但是，现有的大有效面积光纤（ＬＥＡＦ）存在着零色散斜率高、对弯曲敏感等问题，对于陆上应用并不理想，最适于海缆应用。性能全面优化的大有效面积光纤正在发展中。     

Long-term monitoring of polarization-mode dispersion of aerial optical cables with respect to line availability

Physical and technical limits become important when trying to increase data transfer rates to tens of gigabits and higher for already installed optical cables. Polarization-mode dispersion (PMD) is one of the crucial transmission constraints, especially for aerial cables exposed to environmental stresses. Optical fibers in the laboratory and three aerial optical fiber cable links across the Swiss alps were characterized with respect to PMD. Long-term measurement results are correlated to weather data along the cables, and predictions regarding line availability are made.     

解析最新修订标准YD/T 981.3—200x——《接入网用光纤带光缆第3部分：松套层绞式》

介绍和解析了最新修订的YD/T 981.3-200x《接入网用光纤带光缆第3部分：松套层绞式》通信行业标准内容的主要变化和标准对光纤带层绞式室外光缆产品在制造和应用领域的指导作用。     

改进光纤PMD的光纤旋转技术

分析了偏振模色散(PMD)及其不稳定性对系统传输距离与传输速率的影响.介绍了光纤旋转技术,采用正弦旋转技术可有效降低光纤的双折射并增加模式耦合.研究了采用正弦旋转技术制备的旋转光纤的PMD稳定性,旋转光纤成缆后的PMD典型值可控制在0.04 ps/km,与非旋转光纤相比,旋转光纤的PMD具有很好的温度稳定性与成缆稳定性.     

偏振模色散仿真器特性研究

光纤通信线路的偏振模色散已成为高速、长距离光纤通信系统发展的主要障碍之一 ,其特性、测量以及补偿方法的研究成为目前光纤通信研究热点之一。偏振模色散仿真器 ,用于仿真传输链路的偏振模色散特性 ,不仅可用于偏振模色散补偿器 ,也可用于高速长距离光纤通信系统的规划设计等。本文分析了光纤偏振模色散仿真器的研究现状 ,归纳总结了现有偏振模色散仿真器的设计原理和结构特征 ,并用蒙特卡罗法对常用的偏振模色散仿真器的特性进行了数值模拟     

Spatially resolved PMD measurements

Spatially resolved measurements of polarization properties of fiber optic link-such as birefringence, polarization-mode dispersion (PMD) and polarization dependent loss (PDL)-may be effectively performed using polarization sensitive reflectometric techniques. In particular, this paper focuses on polarization-OTDR and reviews its theory and applications. Special emphasis is given to the use of optical reflectometry as a tool to characterize fiber birefringence. This allows to inspect the fiber while cabled and, consequently, to test and improve the cabling process. In addition, it also allows to define reliable mathematical models, which are essential for the design of low polarization mode dispersion fibers. The application of polarization-OTDR to polarization mode dispersion and polarization dependent loss measurements is also discussed.     

Time evolution of polarization mode dispersion in optical fibers

The fluctuation of polarization mode dispersion (PMD) due to environmental change is an important issue for fiber-optic communication systems. We measure the time evolution of PMD for installed aerial and buried cables and for a spooled fiber in a temperature controlled chamber. The results show that PMD fluctuates much more rapidly for aerial cables than for buried cables. The magnitude of PMD is different for the three fibers and our results also show that the magnitude of PMD fluctuation depends on the magnitude of the PMD     

PMD compensation using birefringence photonic crystal fiber in 40Gbit/s optical communication system

A birefringence photonic crystal fiber is used for PMD compensation in a single-channel 40Gbil/s-speed optical communication system with CSRZ format. The experimental results of transmission show that the PMD compensation system works effectively.     

Measure of twist-induced circular birefringence in long single-mode fibers: theory and experiments

Production defects and external perturbations cause standard telecommunication fibers to be randomly birefringent. Fiber birefringence is the origin of the well-known polarization mode dispersion (PMD), which degrades system performances. The knowledge of birefringence properties may be crucial, especially when problems like development of low-PMD fibers or PMD interaction with optical nonlinearities in very high-capacity systems are faced. Some techniques are known to measure birefringence, and useful results have been obtained for both installed and wound-on-drum fibers. However, measurement of the circular component of birefringence still presents difficulties. In this paper, a new method for circular birefringence measurement is proposed that applies to long single-mode twisted fibers. The technique is based on polarization-sensitive optical time-domain reflectometry. Experimental results are in good agreement with the theoretical analysis.     

Stress investigation in optical fiber ribbon cable by means ofpolarization sensitive techniques

We present experimental results on stress behavior in high-density optical ribbon cables, performed by means of two techniques: polarization mode dispersion and polarization optical time-domain reflectometry. Correlation between them and theoretical estimates demonstrate that in such cables part of the birefringence is deterministic     

Analysis of the polarization evolution in a ribbon cable usinghigh-resolution coherent OFDR

Exploiting the inherent polarization dependence and good spatial resolution of optical frequency domain reflectometry (OFDR), the beatlength in a ribbon fiber can be straightforwardly measured. The results clearly show the different amount of polarization ordering for inner and outer ribbon fibers due to the stress-induced birefringence from the common outer coating     

Influence of linear birefringence on Faraday effect measurement for optical fibers

The influence of the linear birefringence on magneto-optical property measurement for optical fibers is investigated theoretically and experimentally. The evolution of polarization in fibers is simulated by the Jones matrix. To verify this theoretical model, a magneto-optical system is built to measure the input azimuth, output azimuth and ellipticity. The Faraday rotation of spun fibers with different pitches is measured. The Verdet constant increases, while the linear birefringence decreases as the pitch becomes smaller. For spun fibers with 1 mm pitch, the Verdet constant can be enhanced by about 20.7% at 660 nm, compared with that of the unspun fiber. The results indicate that smaller linear birefringence can provide more accurate Faraday rotation measurement.     

接入网用光纤光缆技术的发展

 云计算、物联网等新概念的出现进一步推动了全光网的快速发展,其中光网络的接入技术和产品成为光纤技术当前最为热门的话题之一。本文对接入网用的单模光纤特别是弯曲损耗不敏感的单模光纤的研究进展进行了介绍,同时对接入网用光缆的技术和产品进行了分析,详细介绍了几种典型的馈线光缆、配线光缆和入户光缆。