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 a submarine optical-fiber cable using graded-index multimode fibers

This paper describes a designing method for a submarine optical-fiber cable unit consisting of graded-index multimode optical fiber. It has been assumed that excess losses inherent in cable manufacture are dominantly dependant on the lateral force yielded by wrapping tape. The excess losses have theoretically been derived and expressed by optical-fiber unit parameters. Through theoretical and experimental results, the suitable fiber-unit parameters have been given. Based on these investigations, two cable pieces have been fabricated. Excess losses of the cable, which are made with the suitable unit parameters, have been only 0.01 dB/km. This fact may prove the design suitability.     

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.     

50 km, two-repeaters sea trial of optical-fibre submarine cable system

The experimental optical-fibre submarine cable system with 50 km cable and two repeaters was successfully laid in early June 1982. Optical loss changes of the cable during laying were less than 0.003 dB/km. The experiment will be continued during two or three years to obtain data on the cable and the repeaters.     

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     

Optical-transmission characteristics of optical-fiber cables and installed optical-fiber cable networks for WDM systems

Many cables containing 1.3-/spl mu/m zero-dispersion single-mode (SM) optical fibers are installed in trunk and access networks. Recently, there have been a number of studies on wavelength-division-multiplexing (WDM) systems designed to increase transmission capacity and flexibility. If we can construct WDM systems using SM optical-fiber cable networks designed to transmit using wavelengths in the 1.3-/spl mu/m window (O-band), this will prove very effective in reducing construction costs. It is therefore important to examine the wavelength dependence of the transmission characteristics of SM optical-fiber cables and networks that have already been installed and in which several optical fibers are joined. In this paper, we describe the measured optical characteristics of SM optical-fiber cables and installed optical-fiber cable networks at various wavelengths. The optical characteristics were stable in the 1.46 to 1.625-/spl mu/m wavelength range and we confirmed that the installed SM optical-fiber cable networks could be used for WDM system applications.     

Chromatic dispersion characteristics of optical fibre submarine cable under deep sea environmental conditions

First chromatic dispersion characteristics of pure silica-core matched cladding single-mode fibre submarine cable under deep sea environmental conditions are presented. It is confirmed that variations of zero-dispersion wavelength and dispersion at 1.55 mu m wavelength of the cable under hydraulic pressure (0-800 atm), tension (0-6 tons) and temperature change (3-30 degrees C) are less than +or-0.6 nm and +or-0.06 ps/km/nm, respectively.<>     

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     

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.     

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     

海底光缆研究

自从1985年世界上第一条海底光缆问世以来,海底光缆在全世界得到了广泛发展.海底光缆以其大容量、高可靠性和优异的传输质量等优势,在通信领域,尤其是国际通信中起到了重要的作用.文章简要介绍了海底光缆的技术要求,对海底光缆的典型结构作了分析,概述了海底光缆的关键制造技术和施工程序,并指出了其发展趋势.     

Polarisation fluctuation in optical-fibre submarine cable under 8000 m deep sea environmental conditions

Polarisation fluctuation in optical-fibre submarine cable under 8000 m deep sea environmental conditions (hydraulic pressure of 80 MPa, tensile force of 50 kN and temperature of 3°C) are presented. It is found that the frequency spectrum of polarisation fluctuation is less than about 2 kHz in dynamic stress conditions.     

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.     

水底光缆线路的工程设计

水底光缆是直埋光缆的薄弱环节 ,也是光缆设计的一个重要部分。文中以穿越阿什河、蚂蜒河和倭肯河的水底光缆为例介绍了水底光缆的路由选择、长度和程式的确定、敷设要求和施工方式 ,以及岸滩和穿堤保护等方面的设计过程     

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.     

海底光缆安全研究

海底光缆通信具有大容量、通信质量稳定可靠,隐蔽性好,抗毁、抗干扰能力强等特点,成为现代洲际通信的主力.从介绍海底光缆通信系统的组成入手,分析了影响海底光缆传输线路安全和光缆所传输信息安全的主要因素,提出了光缆质量与施工、故障定位与排除和加强信息传输安全等防护措施.     

海底光缆探测中信号衰减的特性研究

海底光缆故障定位主要采用电场法和磁场法,文章根据传输理论,分别推导了这两种方法下信号在海缆导体中的衰减公式,分析了其衰减特性.数值仿真表明:当故障点与岸端距离达1 000 km时,在某型号海缆中,使用磁场法探测,衰减超过95％;而使用电场法探测,则不到8％,在抗衰减方面,电场法要远远优于磁场法.     

海底光缆结构与发展

简要介绍了海底光缆结构,对海底光缆一般技术要求及结构的发展趋势作了简单说明.     

长距离海底光缆系统的技术动向

随着全球经济一体化和各国实现自身信息化的需求,国际间的通信和信息流量激增,尤其是以因特网为首的多媒体通信急剧发展,４５Ｍｂ／ｓ、１５５Ｍｂ／ｓ国际数字专用线业务的需求量逐年增加,造成了通信容量不足,因此为海底光缆通信提供了广阔的市场空间。本文将对长距离光放大海底光缆系统的开发现状、主要技术和发展动向进行探讨。