Fiber cable design and characterization

Optical-fiber cable design differs from the design of metallic cables principally because of two factors: i) the physical properties of fibers are more limiting than those of metals, and ii) the transmission performance of a fiber can be altered by cabling operations due to a phenomenon called microbending. After reviewing these factors, methods are considered for mitigating their effects by appropriate design procedures. This leads to the consideration of different types of cable structures. In order to evaluate an optical cable design, it is necessary that its important mechanical and optical properties be characterized. The tensile, bending, and impact performance, as well as cabling added loss, temperature dependence of loss, and concatenated fiber bandwidth are then considered. The paper concludes with a discussion of "long-term" stability of optical cables.     

Physical Design of the SL Repeater

SL undersea fiber-optic cable allows for the installation of multiple pairs of fibers in the same cable. Using the same high-pressure repeater housing as used in previous undersea systems (and thereby accruing the benefits of no tooling costs and proven handling methods), we are able to mount six optical regenerators. This group of regenerators will dissipate approximately 30 W in service. Previous undersea repeaters dissipated approximately 8 W and achieved a maximum internal temperature of 5° C above the repeater ambient. That might imply a temperature of 20° C above ambient for the SL repeater, which would be intolerably high for reliable undersea performance and longevity. The main thrust of the SL design was to lower this temperature rise. We have achieved a design which is capable of dissipating 30 W with only 4°C temperature rise. This paper describes the design steps necessary to achieve this result and examines the overall repeater structure showing its special design features for accommodating fiber sealing and jointing.     

高压光纤复合测温电缆的研制

为利用光纤分布式温度监测系统对运行电缆的温度进行实时在线监测,自主开发了高压光纤复合测温电缆。对高压光纤复合测温电缆结构设计、光纤内置等制造过程和性能检测进行了较为详细的阐述。     

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.     

Measurement of longitudinal strain in optical fiber cables during installation by cable ploughing

This paper reports a series of experiments in which a number of optical fiber cables were installed using cable ploughing equipment. The elongation of fibers in these cables was monitored during installation in order to assess whether excessive strain levels were encountered. The experiments confirmed that optical fiber cables can be satisfactorily installed using such techniques, and that residual strain levels were sufficiently low that the fiber lifetime was not prejudiced. It was found that optical fiber cables that are flexible and in which fibers are loosely housed can be installed with lower strain levels than other cables. A range of cable-ploughing equipment was used, and equipment which controlled the rate at which cable was fed from the cable drum was found to yield the best performance.     

光缆应急快速抢修盒的设计及应用

光缆中出现一根或数根光纤发生纤芯断裂、损耗增大等故障时,采用传统方法修复须将故障光缆在故障点切断,这种作业方法工作量大,接续时间长,将正常光纤截断,人为地增加了光纤系统的阻断时间和正常光纤的损耗,造成"非故障阻断".光缆应急快速抢修盒可以快速、准确地对故障光纤实施抢通,并最大限度地不影响正常光纤通信,可有效提高光纤系统的可通率.     

First measurement of strain distribution along field-installedoptical fibers using Brillouin spectroscopy

Strain distributions along optical fibers in a 1.3-km-long cable before and after installation are measured using Brillouin optical-fiber time domain analysis. The residual strains in the installed optical fibers were found to vary from zero to 0.07%, depending on the conduit configuration and installation procedure. Strain distribution measurements were carried out on a 24-fiber slotted-core type single-mode optical fiber cable for 1.55-μm-wavelength transmission, whose length, outer diameter, and weight were 1.3 km, 14 mm, and 0.18 kg/m, respectively. No clear relation between strain distributions and the fiber configuration in the test cable are found     

高压电缆用分布式光纤传感检测系统

电力电缆线路运行时的温度和应变在线检测是保障电力系统安全与稳定的必要措施。介绍了用于高压电缆在线监控的分布式光纤传感检测系统方案。详细阐述了检测系统中测量设备的选择,研究了适用于电力系统复杂环境中的温度和应变测量的新型传感光纤——碳密封涂覆光纤,并对这种传感光纤的安装方式进行了探讨。分布式光纤传感检测系统将在高压输电电缆系统的在线检测方面有很大的应用前景。     

Quadrature phase shift technique for measurement of strain, opticalpower transmission, and length in optical fibers

A quadrature phase shift (QPS) technique is described that simultaneously measures the mechanical strain and optical power transmission on multimode and single-mode fibers. The principles of delay and power measurement are separately developed to derive the theoretical basis of the combined technique. The principles of the technique and its practical implementation are discussed. The technique is implemented using stabilized light-emitting diode sources which, unlike laser diodes, are insensitive to back reflections and allow any test wavelength in the usual wavebands to be chosen while being completely eye safe. Measurements on typical fiber and cable samples using a commercial QPS instrument are presented to demonstrate the versatility of the technique. The technique has applications such as cable tensile testing, temperature cycling, and installation monitoring. The technique is capable of state-of-the-art power/strain repeatability and long-term stability. Experimental results are given     

Axial strain in optical-fiber cable manufacture and duct installation

In a tightly-packaged helically wound cable axial strain in both multimode and monomode optical fibers was measured at all manufacturing stages. The results were combined with incremental strains measured for a standard installation process. The results show that on average fiber remained in compression of 0.10 percent after installation and thus would suffer no static fatigue. Some processess gave rise to variations about this average to give a peak strain of 0.09 percent over short lengths of cable, but even this is well inside the limit below which proof-tested fibers should survive for 20 years.     

First sea trial of 1.5-μm submarine optical fiber cable

The first sea trial of submarine optical fiber cable using dispersion-shifted fibers is described. The discussion covers the fiber structural design, cable manufacturing results, fiber splicing, cable laying results, and a high-accuracy measurement technique for optical loss and chromatic dispersion. The results demonstrate the feasibility of long-span, high-capacity 1.5-μm submarine optical fiber cable     

油气管道安全分布式光纤预警系统研究

研究了一种新型的基于Mach-Zehnder光纤干涉仪的油气管道安全分布式光纤预警系统及其基于小波包的信号分析方法。该预警系统沿管道同沟敷设光缆,利用其中的三条单膜光纤构成分布式微振动测试传感器,实时地检测管道沿途所发生的泄漏及其他异常事件,并采用基于小波包分析的"峭度-状态"法辨别管道沿线所发生的异常情况。最后对现场实验数据及其信号处理结果进行分析,结果表明该预警系统可以有效地对管道周围发生的泄漏和其他异常情况进行检测和辨别。     

光电复合海缆温度场建模分析及在在线监测中的应用

为了有效监测光电复合海缆的绝缘状况,基于迭代法改进了IEC60287电缆载流量和温度场计算标准,在有限元数值分析软件包COMSOL中基于热电耦合模块建立了110 kV YJQ41300 mm2海缆温度场模型,与改进IEC60287标准比较验证了建模方法的准确性,在此基础上确定了不同载流量下海缆模型最佳的分析范围。建模研究了海缆正常运行和绝缘性能下降情况下载流量和环境温度对光纤温升的影响;采用介质损耗表征绝缘状况,分析获得了典型介损值下光纤相对温升的变化规律。结果表明:正常情况下光纤温升随载流量的增加近似成平方增大,随环境温度的增加近似线性增大,增速较慢;海缆绝缘性能下降时光纤相对温升随tan的增加成正比增大,相对而言,受环境温度的影响很小。根据上述研究,提出了基于光纤相对温升和海缆载流量的介损计算公式和基于光纤相对温升的海缆绝缘状态监测方法。较之现有基于电气量的绝缘监测方法,该方法不易遭受电磁干扰的影响。在光电复合海缆在线监测方面具有参考应用价值。     

紧套光纤的关键制造技术

简要归纳了紧套光纤的主要技术要求，对比介绍了改善紧套光纤缓冲层剥离性以及室内光缆低温性能的几种方法。最后介绍了近年来紧套光纤设计和制造技术的新进展。     

Optical Fiber Cable Installation Techniques

When installing junction optical fiber cable, which essentially must be longer than conventional metallic-conductor cable to effectively reduce splice loss, the applied tensile load must be within tolerable limits to prevent an increase in loss and a decrease in lifetime. It has recently become possible to meet this requirement through the development of a new cable installation system which makes use of a modified cable pulling truck and a new intermediate cable pulling machine. Furthermore, this new installation system, capable of achieving a 1.0-1.5 km installation length for all types of cable accommodations, has already been put into practice. In addition, this paper presents three new cable installation techniques for facilitating subscriber optical fiber cable installations under various environmental conditions: a tension-controlled pulling technique, a cable pulling eye attachment technique, and a cost-effective damage-free cable installation technique in older buildings.     

海底光缆的光纤强度

海底光缆是敷设在一个极其复杂的海洋环境中,且敷设的深度各有不同,为适应海底光缆在敷设、回收时所引起的光缆伸长,光纤本身需具有优越的强度。结合断裂机理,着重描述了光纤筛选应变值选择的原则与计算方法及测试结果。此外,还从生产工艺角度出发,阐述了提高光纤强度与性能的措施。     

Fiber Optic Placing, Splicing, Testing, and Cable Design Experience at Bell Canada

Bell Canada has passed the stage of field trials and is now into the day-to-day operations, maintenance, and installation of FD-135 (135 Mbit/s) fiber optic transmission systems. The outside plant cables are manufactured by Northern Telecom and consist of a central stranded steel strength member with an extruded plastic slotted profile. Fibers, as well as two copper pairs which are used for servicing purposes and pressure monitoring, are loosely placed in the slots. Manually cleaved fibers are spliced with a V-groove alignment fusion set and are protected by a plastic splice package. Splice packages are inserted in an orderly fashion into an organizer tray which is then placed into a plastic closure allowing for pressurization and easy access of the cable. This paper provides an overview of the outside plant hardware and describes the various installation, splicing, and cable testing techniques that have been successfully used by Bell Canada.     

薄膜型光纤温度传感器的膜系设计

纳米薄膜与光纤的结合为新型感测提供了各种潜在可能.为了分析温度敏感薄膜的膜系设计及其对光纤温度传感器传感特性的影响,根据光学薄膜理论和光纤传感器的温度感测原理,探讨了光纤温度传感器中敏感薄膜的膜系设计,并构建了薄膜型光纤传感器的温度传感特性模型.以测试系统的参数、性能以及其对干涉光谱的要求为基础,设计了对称性较好的法布...     

挠性光电印制电路板工艺光纤特性仿真与测试

挠性光电印制电路板(Flexible Electro-Optical Printed Circuit Board, FEOPCB)在高温层压制作过程中,埋入光纤会产生热应力,造成光纤损坏等缺陷,影响其可靠性和高速信号传输性能。为了降低FEOPCB弯曲半径并提升其可靠性,将在双面覆铜聚酰亚胺(PI)基板上设计制作高精度矩形光纤定位槽。首先建立有/无涂覆层光纤埋入挠性基板有限元仿真模型,对FEOPCB制造工艺进行模拟仿真,并对埋入光纤应力及影响因素进行分析。结果表明,有涂覆层光纤所受应力远小于无涂覆层光纤。针对有涂覆层光纤,采用激光刻蚀技术在双面覆铜PI基板上制作了高精度矩形定位槽,通过高温层压工艺完成了FEOPCB制作。FEOPCB完成了温度冲击、低温、高温、湿热和10万次弯曲疲劳可靠性试验,利用光学显微镜观察分析,埋入光纤无高温降解和破裂等缺陷。FEOPCB最小弯曲半径小至2 mm,弯曲损耗分别为0.57 dB (90°)和1.12 dB (180°),且相邻光纤之间无串扰,在850 nm波长条件下通信速率可达10 Gbps,误码率小于10^-16。     

Design and performance of nonmetallic waterproof optical fibercable using water-absorbent polymer

A nonmetallic optical fiber cable waterproofed with absorbent polymer was developed. Methods are proposed for evaluating the reliability of absorbent polymer in order to apply it as a waterproofing material, and a type of polyacrylic acid is selected. In addition, a waterproofing design is established based on a theoretical estimate of the water penetration length in the cable space. Among other findings, it was shown that the optical fiber loss of water-penetrated cable increases due to freezing. The allowable penetration length of waterproof cables can be determined so as to suppress this loss increase. Cables manufactured using this new design and absorbent polymer showed performance sufficient for practical application