A 150-km repeaterless undersea lightwave system operation at 1.55 µm

A repeaterless undersea cable system spanning 150 km between a shore site and an off-shore floating platform is to be installed early in 1985. The system uses single-mode fibers to carry data at a line rate of 3.088 Mbit/s. Laser transmitters operating at 1.55 μm and p-i-n receivers complete the optical system. This paper discusses system parameters and performance, and both terminal and undersea equipment.     

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     

Undersea fiber cable technology

Compared with the conventional coaxial undersea cable systems, an optical fiber undersea cable system has a great technical and economical advantage. It is also suitable for digital transmission. In this paper, the optical fiber undersea cable technology (including optical fiber cables and repeaters), which is now in the research and development stage in several countries, is reviewed.     

基于ArcSDE的海缆温度监测系统的设计与实现

采用SQL Server 2005配合ArcSDE作为后台数据库来管理地理信息数据和海缆的各种属性信息;系统选用Visual C#平台以及ArcGIS Engine组件作为前台开发工具开发海缆监测系统。通过对ArcSDE空间数据引擎存储模式的理解与运用,系统实现了海缆温度数据导入,加载显示以及温度数据的入库等功能。按照ArcSDE中空间数据和属性数据的管理规则设计数据库,利用了组件开发技术,进行了桌面平台系统的总体设计与实现。     

The FLAG cable system

The Fiberoptic Link Around the Globe (FLAG) cable system is a 10 Gb/s synchronous digital hierarchy (SDH) based undersea fiber optic network. When fully operational, FLAG will connect 12 countries with over 120000 voice channels via 27000 km of mostly undersea cable. FLAG will incorporate a new generation of undersea fiber optic system that uses erbium-doped fiber amplifiers and will be jointly supplied by AT&T Submarine Systems Incorporated (SSI) and KDD-Submarine Cable Systems (SCS) Inc. When completed, FLAG will meet or exceed all relevant international performance standards, have greater reliability and availability than previous systems in the region, and conform to all ISO 9000 quality standards with respect to design, development, production, installation, and service     

Recent progress in amplified undersea systems

The advent of the optical amplifiers has removed the loss limitation of the fiber in the conventional undersea systems using 3R (retiming, reshaping, regenerating) repeaters, and it has introduced new design criteria for the undersea lightwave systems. The accumulation of the small impairment factors that was negligible in the conventional system becomes significant to determine the transmission performances of the amplified system. The fiber nonlinearity is a distinctive limitation factor that dominates the transmission performance of the amplified system, although it was not a limitation factor in the conventional system. This paper describes the recent progress of the undersea lightwave cable systems employing optical amplifier repeaters. The limitation factors and the polarization dependent characteristics of the amplified system are described. The system demonstrations with conventional IM-DD technology are presented using both recirculating loop and straight fiber transmission line. The system maintenance method is also explained briefly. Future technologies adopting the WDM or the optical solitons are also discussed     

发展中的亚太海底光缆产品及市场

围绕着整个亚洲—太平洋地区海底光缆的应用情况及其市场因素进行了分析和讨论。内容涉及到目前的越洋海底光缆话路容量、对于此类话路的市场需求及其市场驱动原因、目前海底光缆的关键技术、近期的市场活动及其发展趋势、正在筹划中的海底光缆项目等。     

Shore-to-Undersea Visible Light Communication

In this paper, a novel visible light based shore-to-undersea (S2US) communication is proposed. It considers various properties of both maritime and undersea environments such as wave height, wind speed, and absorption. A lighthouse transmits the signal using white light emitting diodes (LEDs) and this signal is received by a buoy that acts as a beacon to relay to the undersea receiver. The beacon employs the decode-and-forward (DF) method in such a way that green LEDs transmit the DF processed signal to the undersea receivers via the undersea optical channel. The performance of the proposed S2US system was first evaluated via simulations with the JONSWAP spectrum model representing the maritime optical channel and the Jerlov water type representing the undersea optical channel. The results show that the transmitted signal undergoes significant attenuation, particularly over the undersea optical channel. At the reference distance of 1.025 km with Jerlov water type I, a bit error rate performance of 10^?4 is achieved with a data rate of 1 Mbps. The S2US was further verified with experiments in terms of received signal level on a laboratory scale. The comparative analysis demonstrates that the simulation and experiment results are in good agreement.     

Applying WDM technology to undersea cable networks

WDM technology is now being applied to international undersea fiber optic cable networks in order to provide enhancements such as increased network capacity and greater network flexibility. This article looks at what WDM technology can provide, the progress being made, and the special challenges in its application in undersea networks. We then describe several international undersea networks that, when completed by the end of 1999, will use WDM technology and will serve as a major part of the global undersea fiber optic infrastructure connecting the world     

海底光缆网络远程供电技术研究

传统的有中继的海底光缆传输系统由端站的远程供电设备（PFE）对中继器等有源设备进行供电,而海底光缆网络的远程供电系统更加复杂,为此在介绍了传统海底光缆传输系统的远程供电系统的基本原理后,重点对海底光缆网络的两种远程供电方式——串联和并联供电方式做了分析,分别对其供电效率进行了计算,并做了比较。     

Laser Transmitter for Undersea Communications Using Third-Harmonic Generation of Fiber-Laser System at 1.5 μ m

We report a viable laser transmitter for free-space undersea communications. An all-fiber, picosecond, Watt-level master-oscillator-power-amplifier (MOPA) system at 1.5 mum based on rapid amplification of mode-locked pulses in heavily Er:Yb codoped phosphate fiber is combined with fiber pigtailed lithium niobate intensity modulator (pulse picker), to construct a fully integrated eye-safe transmitter operating at 65-Mb/s data rate, that can be used in intermediate-range (few kilometers) atmospheric communication links. For undersea use, the output of the MOPA system is frequency-tripled into the blue-green transparency window of ocean water. The wavelength conversion occurs in a simple single-pass setup utilizing a sequence of two periodically poled lithium niobate crystals, both of which are operated at room temperature. The conversion efficiency from fundamental to third harmonic reached 14% and resulted in generation of 140 mW of average power at 518 nm. The conversion efficiency can be straightforwardly increased threefold using properly antireflection-coated optics in the free-space part of the setup, and the data rate can be scaled up into the gigabit-per-second range by using a faster mode-locked oscillator in the MOPA system.     

The SL Undersea Lightguide System

A digital optical fiber undersea cable system targeted for transatlantic service in 1988 is now under development at Bell Laboratories. The system uses single-mode fibers to carry data at a bit rate of 280 Mbits/s. Using digital speech compression techniques, a total system capacity of over 35 000 two-way voice channels can be realized. With laser transmitters at 1.3 μm, repeater spacings are expected to exceed 35 km. This paper discusses system parameters, repeaters, fiber and cable design, terminal equipment, and system measurements.     

The glass necklace [FLAG submarine fibre-optic link]

The longest ever man-made structure is being assembled in the world's most ambitious undersea lightwave communications system. When completed in 1997, the system will link Great Britain and Japan by a complex undersea optical-fiber cable that will span 27,300 km-more than two-thirds of the Earth's circumference. Called the fiber-optic link around the globe (FLAG), it will snake in eight sections through the Atlantic Ocean, the Mediterranean and the Red Seas, the Indian Ocean, and the Pacific Ocean. The authors describe how the backbone of FLAG is third-generation transoceanic optical-fiber cable technology     

Africa ONE: the Africa Optical Network

Describes the architecture of the Africa Optical Network (Africa ONE) that will encircle the entire continent of Africa with an undersea fiber optic ring network. Using a combination of wavelength-division multiplexing (WDM) and synchronous digital hierarchy (SDH) multiplex and cross-connect equipment, Africa ONE brings together a unique blend of technology to achieve network robustness. The article traces the need for this regional network and how it fits into the global undersea communications network. Also the authors describe the network elements that make up the transmission topology, the methodology used for interconnecting each African country to this network, protection and restoration of the network, and the network management system. Africa-ONE is a 40,000 km trunk and branch network that is planned to be ready for service in 1999. The present article presents the architecture of the undersea portion of the Africa-ONE project     

光纤外护套绝缘故障的监测

为了保障长途海底光缆的运行可靠性，需要尽早发现潜在的故障。本文介绍了一种监测海底通讯光缆外护套电绝缘性能的方法。该方法使用微控制器控制高压信号源，并同时精确控制测试电流。使用这种方法可以早期发现海底光缆的损伤。     

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.     

Optical undersea cable systems trends

This paper reviews the evolution of undersea cable technology from the telegraph cables of the mid-nineteenth century to the optical undersea cables of today. Future systems will use optical fiber amplifiers which offer significant technical and economic advantages. Consequently, emphasis is placed on problems associated with the accumulation of small, second-order effects in long lengths of optical fiber and, specifically, their impact on the 5-Gb/s optically amplified transoceanic undersea systems scheduled to be deployed in 1995. Technology options for achieving further capacity increases, among them the use of optical solitons, and trends toward networked undersea cable systems with automatic restoration features are described     

CTNE undersea lightwave inter-island system

The world's first deep-water undersea repeatered lightwave cable system will be installed in the Canary Islands in 1985. The three-repeater 120-km 1.3-μm system will be used initially to prove-in the SL Undersea Lightwave System and later to provide commercial service to CTNE.     

CTNE Undersea Lightwave Inter-Island System

The world's first deep-water undersea repeatered lightwave cable system will be installed in the Canary Islands in 1985. The threerepeater 120-km 1.3-μm system will be used initially to prove-in the SL Undersea Lightwave System and later to provide commercial service to CTNE.     

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.