Strain of optical fibres of an optical submarine cable on the sea bed

The letter describes strain of optical fibres of an optical submarine cable on the sea bed. The test results of the sea trial show that the strain of optical fibres will be relaxed by the lower temperature and the higher pressure on the sea bed.     

超长光电复合海缆光缆单元的研发与制造

本文介绍了超长光电复合海缆光缆单元的研发和制造,该光缆单元是35KV光电复合海底电缆中的通信单元,由于海底电缆接续技术复杂,不允许有接头,要求单盘光缆长度超过36公里,本文论述上述光缆的基本结构、设计思路、工艺控制、试验结果等。     

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     

浅谈海底观测网试验系统用深海光电复合缆

深海光电复合缆是构成海底观测网的主干部分,用于连接海岸基站与海底接驳设备,实现它们之间的电能供给和通信数据传输。主要介绍了适用于海底观测网试验系统的深海光电复合缆的结构选择依据和性能设计。     

7000 m deep sea trial of OS-280M optical-fibre submarine cable system

The letter reports the 7000 m deep sea trial of an experimental OS-280M optical-fibre submarine cable system, consisting of a 24 km optical cable and two monolithic IC submarine repeaters, which was successfully carried out in February 1984.     

First sea trial of FSK heterodyne optical transmission system usingpolarisation diversity

Operations of an FSK heterodyne optical transmission system on the cable ship during the cable-laying, holding, and recovering process in a 6000 m-deep sea trial is demonstrated. It is shown that polarisation diversity is a powerful technique for application to optical fibre coherent systems in submarine cable systems     

The Submarine Optical Cable of the Submarcom S 280 System

Submarine optical telecommunication cables must satisfy a large number of specific items. To comply with specifications, CDL has developed a cable structure based on high-performance optical fibers placed with slack in the grooves of a plastic rod put in the center of a very strong cable. The deep-sea cable is the basic structure for armored cables or land cables. Armor transitions are designed to minimize cable twist. The couplings are designed to give a good optical electrical and mechanical continuity between the cable and the repeaters. The deep-sea repair is designed to be achievable on a cable ship. The cables, repairs, and couplings have successfully sustained several sea trials and two experimental links are now operating. No increase of the attenuation of the optical fibers in the cable have been noticed on the 19-month old first link. The development of the S 280 cable is proceeding on the right track.     

Characteristics of wire-space-type submarine optical cable

A new type of submarine optical cable, called wire space cable, is proposed for utilisation in shallow sea areas. In the cable, optical fibres are inserted into spaces formed between stranded wires, which are used as tension members. It has been found from a cable pulling test that nonarmoured cable elongation at 8000 m in water depth is 0.3% and armoured cable elongation at 6000 m is 0.5%. Furthermore, a hydraulic pressure test has shown that single-mode-fibre loss at 1.3 ?m wavelength does not increase up to a water depth of 2700 m.     

Studies on designing of submarine optical fiber cable

This paper describes important studies necessary to design submarine optical fiber cables. These include a study for deciding the optimum single-mode fiber parameters to suppress losses during cabling, cable laying, and so on. It also includes a study on the necessary fiber proof test conditions to prevent fiber breakage during cable handling, that is, during cable laying and recovery and to assure long-term fiber reliability. Submarine optical fiber cable sea trial results are also stated for cables designed applying these studies.     

Estimation of submarine optical-fiber cable elongation

The tensile strain on a submarine optical-fiber cable may reach a nonlinear elastic region when recovered from the sea floor. In this paper, a method is shown to characterize cable elongation up to the nonlinear plastic region by extending wire theory previously developed to evaluate cable strain in the elastic linear region. The results of applying this method to several optical-fiber cables agrees well with tensile test results of the cables when cable ends are prevented from twisting, as well as when they are free to rotate. Also, by evaluating the dependence of cable strain on cable materials, such as stranded-strength members and pressure-resistant conductor pipe, a practical submarine optical-fiber cable structure for deep-sea use is determined.     

Design of Deep-Sea Submarine Optical Fiber Cable

On designing optical fiber cable, it is necessary to deal with optical fiber weakness, such as small breaking elongation compared to metal materials and excess loss under both lateral and hydraulic pressure. This paper presents a structural design method for the submarine optical fiber unit and cable based on the study of both lateral and hydraulic pressure characteristics. This paper also clarifies that the fiber proof test level has been determined for new cables to be applied in sea areas 8000 m in depth.     

Sea trial of submarine optical amplifier repeater system using travelling-wave semiconductor laser amplifier

An optical amplifier repeater system consisting of semiconductor laser amplifiers was evaluated in 3000 m deep sea at 820 Mbit/s in the 1.5 mu m wavelength region using 23.5 km of optical submarine cable. The repeater output power was stabilised by an APC system monitoring amplified optical signal power. The authors confirmed stable digital signal transmission and the reduction of variation in the repeater output power for changes in the polarisation of the input signal.<>     

1.3 ?m, 400 Mbit/s undersea optical repeater sea trial

A sea trial of a 1.3 ?m, 400 Mbit/s undersea optical repeater1,2 connected with a 1.3 km-long undersea optical cable was conducted in Sagami Bay at about a 700 m depth in January 1981. Stable performance for the repeater was confirmed, as it withstood such external mechanical forces as heavy tension, water pressure, vibration, shock and extreme temperature change during laying and recovering.     

Proposal for stimulated Brillouin scattering suppression by fibre cabling

A new optical unit structure which can suppress stimulated Brillouin scattering (SBS) is developed. The Brillouin gain bandwidth is expanded by distributing the fibre strain in the optical unit. The expansion depends on a unique strain-holding double-stranded optical unit structure. This is the first proposal for suppressing SBS by cabling. A 3.7 km long cable was laid in the sea and its Brillouin gain bandwidth was measured. The bandwidth was expanded 2.9 times with a cyclic strain amplitude of 0.08%.<>     

Polarisation fluctuations of optical fibre submarine cable in 6000m deep sea trial

The difference between the polarisation fluctuations of an optical fibre submarine cable during laying and recovery in a 6000 m deep sea trial is discussed. State of polarisation variations in real time (≃ 6 msec) were measured by a Stokes parameter analyser using an LiNbO₃ device. The maximum power spectra of the polarisation fluctuations during cable laying and recovery were less than 50 Hz     

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。     

Repeaterless undersea lightwave systems

A repeaterless undersea lightwave system connects two terrestrial locations separated by the sea without the need for undersea regeneration of the optical signal. To achieve the longest span length possible, the system combines terrestrial terminals containing superior-performance optoelectronic devices with ultrareliable undersea cable technology. The lightwave technology used to achieve cost-effective, long-span repeaterless undersea lightwave systems is discussed. This includes undersea fiber and cable, lasers and receivers, and terminal equipment. The first application of this technology, Taiwan's Tainan to Peng-Hu system, is described. The possibilities for increasing the maximum attainable span length of high-capacity repeaterless undersea systems are examined. Key elements are higher-output transmitters, more sensitive receivers, and improved optical fibers     

基于BOTDA技术的电缆温度监测

由于海底电缆深埋海底,其运行状态的监测尤为重要。因此,提出基于光纤光时域反射（OTDR）的布里渊时域反射分析技术（BOTDA）的分布式光纤传感器对复合海缆进行温度监测。简单介绍了BOTDA技术的原理以及温度监测的实验。对实验测得数据进行数据拟合处理和分析。从实验的数据分析中得出基于BOTDA技术测量出电缆温度的变化趋势和实际温度变化趋势是基本吻合的。从而验证了该技术测温误差小、响应时间短、运行可靠且能实现长距离测量,可有效应用于电缆温度在线监测,为电缆导体温度的确定提供有效的参考依据。     

Deep sea trial of 1.55 μm optical fibre submarine cable system

The first 6000 m deep sea trial of a 1.55 μm optical fibre submarine cable system was successfully conducted in the Pacific Ocean, near Torishima Island, in January 1988. By using 1.55 μm loss-minimised single-mode fibre cables and submerged fully monolithic Si-IC regenerators with DFB lasers, excellent transmission performances at 140, 280 and 565 Mbit/s were obtained through 150 km repeater spacings, respectively     

Performance monitoring of long chains of optical amplifiers

The monitoring and fault location of long chains of optical amplifiers such as will be deployed in undersea cable systems is an important design consideration. The Letter describes two methods which have been proposed and one which has been evaluated on the authors' test bed simulator of 3100 km with OAs spaced at 45 km and operating at 5 Gbit/s.<>