单模光纤系统中继距离的统计设计方法

本文根据实际的光功率概算参数分布,用统计法对140Mbit/s单模光纤系统的中继距离进行了设计。结果表明,当系统先期失效率为0.1％时,按统计法设计的最大中继距离可以比传统的最坏值法加长17公里。进而,我们还提出了一种简化的统计设计法,可以避免完全统计法的计算复杂性,同时又保留了其主要优点。     

新技术

新技术节省中继器的光传输方法德国ＨＨＩ公司光信号处理科研人员研究出一项称作光相位耦合新技术。该技术用于光传输线路中，可使两信号中继器之间的距离延长，减少中继器一半左右。应用光相位耦合技术，较高频率与较低频率在线路中间交换位置，从而放慢速度，使发射机发...     

密集波分复用DWDM技术与超长距离传输

光传输技术发展非常迅速，特别是线路系统，其传输速率的提升是所有技术中最快的，这主要归功于ＷＤＭ系统的快速发展。在过去的５年里，没有任何一种传输技术像ＷＤＭ发展那么迅速。在１９９７年之前，很少有人明白ＷＤＭ这个英文缩写代表什么，而今天则很少有人不明白这３个字母缩写的含义。 目前超长距离ＷＤＭ系统传输更是受到制造商、运营商的充分关注。所谓超长距离传输是不采用电再生中继的全光传输，从而大大减少了光／电转换次数，降低传输成本，提高了系统的传输质量和可靠性。实际应用中，无电中继传输距离达到３ ０００ｋｍ，在…     

光传输中继段长的设计

本文根据目前光纤通信技术水平以及ＩＴＵ－Ｔ和国际的有关规定，结合工程设计实例，分别阐述准同步（ＰＤＨ）传输和同步（ＳＤＨ）传输系统光传输系统中继段中的设计。特别是在确定超长中继距离时，如何考虑系统的兼容性和如何恰当选取计算参数作为详细的分析。最后指出，在现有的通信技术条件下，光传输系统所能达到的最长中继传输距离。     

海南省全岛数字电视网改光传输系统设计——概述及经验总结

本文主要结合海南全岛广电网络已有的光缆资源来进行有线电视光传输系统设计，重点阐述了光链路设计的要点、点功率的计算方法。     

新一代光通信技术

光通信技术将从研究光纤的固有性质向研究光的性质,如载波(Carrier)方向发展。具体技术有:①超高速/超长距离传输技术;②光波通信技术;③光信号处理技术。实现超高速/超长距离传输技术将采用相干光传输技术,这样,接收灵敏度可提高十几dB,中继距离将达到100km。如采用光纤放大器,中继距离会增加到400km左右。在理论上,光纤放大器的中继距离为5000～10000km。目前,已制定其技术开发目标:①超高速电     

介绍一种光链路设计的快速计算方法

主要介绍了利用Excel表格快速计算有线电视光传输系统设计中的各项指标，根据此方法可减少光链路设计中反复的功率转换和枯燥的计算步骤，大大提高设计准确性和效率。     

超长距离光传输技术在网络中的应用

超长距离光传输技术的研究已经开展多年，相关的实验室测试和现场试验已经证明了超长距光传输的可行性。超长距光传输中所应用的相关技术，已从实验室进入到市场应用，我国也已经制定出版了超长距光传输相关的通信行业标准。在市场需求的推动作用下，构架一个高性能、低成本的基础光网络逐渐成为运营商考虑的重点。     

浅谈光纤通信超长距离传输的方法

光纤通信技术(optical fiber communications)从光通信中脱颖而出,是现代通信的主要支柱之一,对现在电信网起到了非常重要的作用。光纤通信作为一种新兴技术,崛起速度非常之快、应用面广泛,在通信史上是前所未有的。光纤通信技术世界新技术革命的重要标志,对未来信息社会的各种信息传递也是非常重要的。对于光纤通信技术来说,延长单段无中继光传输距离对于减少网络节点间的电中继和光中继,节约长距离传输成本具有非常重要的作用,本文就光纤通信超长距离传输的方法展开研究和分析。     

广播电视传输系统基础理论知识

干线型光缆传输系统有两种形式，见图6-10所示，当传输距离在30km以下时，采用图6—10（a）所示的光一电一光中继方式1310nm系统。该传输系统由两级光发射机、光缆及光接收机组成。这种系统的发射机采用的是直接调制发射机，其中继对系统性能影响很大，每增加一级中继，载噪比C／N下降4．5dB；C／CTB下降6dB，所以，图6-10（a）所示的光-电～光中继方式1310nm系统，最多只能加入两级中继。当传输距离在（30～150）km时，采用图6—10（b）所示的1550nm系统，可允许将中继放大增加到2～3级，而每增加一级中继，C／N只下降1dB，C／CSO与C／CTB几乎不变。通常，在传输距离允许情况下，如果从经济角度考虑，可以使用1310nm系统。图6—10（C）为干线型光缆网示意图。     

光纤通信工程光纤光缆的验收

给出了光纤光缆产品的主要技术指标和测试方法,讨论了光纤光缆主要技术特性和光纤通信系统申通信容量、中继距离、接续损耗的关系,阐述了光纤光缆验收的基本原则和验收的一般方法。     

OPTICAL FIBER NONLINEAR SOLITON COMMUNICATION

In anormalous dispersion of monomode optical fiber,optical solitons are evolvedfrom optical pulses when the dispersion is balanced by the nonlinearity.Undistorted transmissioncan be realized by using optical solitons,which can offer much greater the transmission capacityand extend the repeater spacing of the fiber communication system.The mechanism of thegeneration of optical solitons is expounded.A few forms of nonlinear transmission equationare obtained by using a concise method.The general complete expression of elementary solitonsolution of the nonlinear transmission equation without loss is given,and the design of the solitontransmission system is discussed.     

Repeater Fault Location for a Submarine Optical Fiber Cable Transmission System

This paper introduces a repeater fault location system for a repeated submarine optical fiber transmission system of 400 Mbits/ s at 1.3μm. The repeater fault location system is used in an out-of-service test. The fault locator transmits a test signal via a main optical fiber line, in order to make a loop-back path in one of the repeaters for returning the test signals via another main optical fiber line and to measure the bit error rate (BER) of the interrogated repeater. The test signal is a kind of pseudorandom signal that includes a low frequency component, which is assigned to the repeater as a supervisory frequency tone (SVT) signal. The BER is measured by counting the number of low frequency signal phase inversions in a time. This paper first describes the test signal generating method, SVT frequency allocation, and the filter design installed in a repeater. Next, there is a discussion of how the capability of the repeater fault locator has been experimentally verified by using two submarine repeaters, including four regenerative repeater units and three submarine optical fiber cables. As a result, a BER of less than5 times 10^{-6}is accurately measured.     

Long-span single-mode fiber transmission characteristics in long wavelength regions

Experimental and analytical results on high-speed optical pulse transmission characteristics for long-span single-mode fibers by using InGaAsP lasers, emitting at 1.1, 1.3, and 1.5 μm, as well as a Ge-APD are reported. At 1.1 μm, 400 Mbit/s transmission experiments were successfully carried out with 20 km repeater spacing. At 1.3 μm, where single-mode fiber dispersions approach zero, error rate characteristics showed that optical power penalties at 100 Mbits/s and 1.2 Gbits/s are negligible even after 30 and 23 km fiber transmission, respectively. It was confirmed that a 1.6 Gbit/s transmission system has 15 km repeater spacing. At 1.5 μm, where silica fibers have ultimately minimum loss, single-mode fiber transmission experiments were carried out at 100 Mbits/s with about 30 km repeater spacing. 400 Mbit/s transmission characteristics using 20 km fibers were also studied. Fiber bandwidths, measured by optical pulse broadenings after 20 km transmission, were 24, 140, and 37 GHz . km . nm at 1.1, 1.3, and 1.5 μm, respectively. Progress in lasers, fibers, and optical delay equalizers at 1.5μm will bring about large-capacity transmission systems having about 150 km repeater spacing. These results reveal fiber dispersion characteristics in the long wavelength region essential to high data rate single-mode fiber transmission system design.     

自由空间全光通信链路的设计方法

在自由空间光通信系统中 ,由于中继距离的不确定性 ,相应的链路传输损耗也不同 ,因而各中继器有不同的增益。针对自由空间光通信的这一特点 ,介绍了一种解决方法 ,即采用具有自动增益控制 ( AGC)的光放大器作为中继器 ,并分析噪声累积对系统性能的影响。结果表明 ,采用掺铒光纤放大器可以得到好的系统性能     

光纤通信技术的现状及发展趋势

简要介绍了我国光纤通信的现状,总结了目前正在使用的波分复用技术和光纤接入技术的基本原理和发展状况,最后从超大容量、超长距离传输技术,光孤子通信技术和全光网络3个方面论述了光纤通信技术的发展趋势.     

Technology for extending transmission distance of EPON system

At present, the maximal transmission distance between the optical line terminal (OLT) and opticalnetwork unit (ONU) of an Ethemet passive optical network (EPON) system is 20 km.However, this distance should be extended to 50 km or even longer in some applications such as fiber to the village (FTTV).A method for extending the transmission distance of an EPON system is proposed in this paper, in which the optical power amplifier and the adjustment of dynamic bandwidth allocation (DBA) are the key technologies.     

Optical Fiber Transmission System Demonstration Over 32 km with Repeaters Data Rate Transparent Up to 2.3 Mbits/s

An initial optical fiber transmission system under development for Army long haul tactical communications is described and evaluated. The system interfaces with the 2.304 Mbit/s data input and output of an Army inventory multiplexer and its orderwire. The system includes transmitter and receiver end terminals, three data rate transparent repeaters, 8 km of graded index optical fiber, plus three optical attenuators and various optical connectors for simulating transmission up to 32 km. Long repeater spacing is achieved using low loss fiber, semiconductor lasers stabilized using optical feedback, and avalanche photodiodes. The system met all of the specified requirements and shows that optical fiber transmission systems have excellent prospects of meeting full military specifications. The versatility of data rate transparent repeaters is achievable even for transmission up to the 64 km distance desired for Army long haul tactical communications.     

A simple expression for optical FDM network scale considering fiberfour-wave mixing and optical amplifier noise

Possible transmission distance and number of channels are studied in optical FDM (frequency division multiplexed) systems. Optical amplifier noise and fiber four-wave mixing, which respectively restrict input power to a repeater and input power to a fiber, are taken into account. A simple analytical expression is derived for evaluating FDM network scale by using a Gaussian noise approximation. Calculation examples are also presented     

一种性能优良的光纤传输中继机

本文介绍一种性能优良的传输全电视信号的实用光纤传输中继机及它的工作原理、性能和指标测量。其性能符合《电视视频通道测试方法》规定的主要指标。经现场试验,该中继传输系统传送一路彩色全电视信号,可延伸传输距离大于20km(光纤损耗0.8dB/km),富余量7dB,传输性能优良,图象清晰逼真,伴音保真度高。