Unit 5
Introduction to Optical
Fibre Communication
四川邮电职业技术学院 2
Contents
? Teaching Objectives
? Revision
? Pre-reading Activities
? While-reading Activities
?New words and phrases
?Text organization
?Text and translation
? Post-reading Activities
? Further Development of the Theme-related
Specialized Knowledge
? Assignments
四川邮电职业技术学院 3
Teaching Objectives
? 1.to know the historical development of optical fiber communication
and its latest development and future
? 2,to understand the main idea and organization of the text;
? 3.to master some important new words,phrases and their usages,
especially the theme-related telecom terms and expressions in the text;
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Revision
? Teacher uses the following exercise to help the students to revise the
important expressions or phrases or sentences which were learnt in
the study of last unit,
? Teacher, When I say a phrase or an expression in Chinese,you
respond by giving an English equivalent your learnt in the study of
Unit 4 Internet,
? Teacher ( Chinese ) Students ( English)
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Revision
? 网络资源 network resource
? 信息服务 information service
? 远程终端 remote terminal
? 电子邮件 electronic mail
? 无线信道 wireless channel
? 搜索工具 searching tool
? 用户界面 user interface
? 文本信息 textual message
? 超文本协议 hypertext protocol
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Pre-reading Activities
? 1,Ask the Ss the following two questions related to the theme of
the text,
? 1) You have exposed yourselves to optical fiber communication in
the study of communication technology-related courses,Any one
would like to define it in your own words?
? Possible Answer,Optical fiber communication is referred to as the
communication with laser as the light source and optical fiber as the
transmission medium,
? 2) Who can tell us its remarkable characteristics?
? Possible Answer,Optical fiber communication is characterized by
large transmission capacity and sound performance anti-
electromagnetic interference
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While-reading Activities / New
words and phrases
? accelerate ［ ?ｋ 'ｓｅｌ ?ｒｅｉｔ］ vt.; vi,加速
? account ［ ??ｋ αｕｎｔ］ n,帐目，报道；说明
? barrier ［ 'ｂ ?ｒｉ ?］ n,隔板，障碍，界限
? breakage ［ 'ｂｒｅｉｋｉ ?］ n,破坏，损耗量
? broadband n,宽频带，宽波段
? bundle ［ ?ｂ ?ｎｄｌ］ n,捆，束
? cite ［ｓａｉｔ］ vt,引用，举 (例 )
? clad ［ｋｌ ?ｄ］ a,穿衣的,(金属 )包层
? commitment ［ｋ ?'ｍｉｔｍ ?ｎｔ］ n,作为，赞助，委托
? community ［ｋ ?'ｍｊｕ,ｎｉｔｙ］ n,团体，社会
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While-reading Activities / New
words and phrases
? dominate ［ 'ｄ ?ｍｉｎｅｉｔ］ vt,支配，统治；处于支配地位
? dopant ［ 'ｄａｕｐａｎｔ］ n,掺杂物，掺杂剂
? emerge ［ｉ‘ｍ ?,?］ vi,出现，形成，浮现
? emergence ［ｉ 'ｍ ?,??ｎｓ］ n,浮现，出现
? endoscopy ［ｅｎ 'ｄ ?ｓｋ ?ｐｉ］ n,内窥镜
? entertainment ［ｅｎｔ ?'ｔｅｉｎｍ ?ｎｔ］ n,招待，娱乐
? evolve ［ｉ 'ｖ ?ｌｖ］ vt,使发展，推论；进展，发展，进化
? favorable ［ 'ｆｅｉｖ ?ｒ ?ｂｌ］ a,顺利的，有利的，称赞的
? feasible ［‘ｆｉ,ｚ ?ｂｌ］ a,可实行的，行得通的，可能的
? purification ［ｐｊｕ ?ｒｆ ?'ｋｅｉ ??ｎ］ n,提纯，净化
? radiance ［ 'ｒｅｉｄｉ ?ｎｓ］ n,发光，容光焕发
? rationale ［ｒ ??ｉ ?'ｎ α:ｌｉ］ n,(某事物的 )基本理由，理论基础
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While-reading Activities / Text
organization
? Text organization
? 1,Ss read the text and point out the main idea of the text,
? The main idea,The text mainly discusses the historical development
of optical fiber communication and its latest development,
? 2,Ss make an analysis of the organization of the text,
? The text may be divided into four major sections,
? Section1 (Lines1-8),introduction of the extent of the recent
development of optical fiber communication through the total length
of installed optical fiber;
? Section2 (Lines9-56),the historical development of optical fiber
communication;
? Section3(Lines57-74),the latest development and future of optical
fiber communication,
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Text and translation
?Introduction to Optical Fibre Communication
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Text and translation
? One of the most important technological developments during the
1980s has been the emergence of optical fiber communication as a
major international industry,One indication of the extent of this
development is the total length of installed fiber1,which was
estimated to be 3.2 million kilometers in the U.S,alone by the end of
1987,Over 90% of this fiber was placed in service2 during the time
period of 1982~1987,Long-haul trunk installations have been
dominated,accounting for3 about 95% of the fiber in the U.S,
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Text and translation
? Although telecommunication is the rationale for most of the current
interest in fiber optics,this was not the case4 during the early days of
the technology,The researchers who produced the first clad glass
optical fibersin the early 1950s were not thinking of using them for
communications; they wanted to make imaging bundles for endoscopy,
Fiber optics was already a well-established5 commercial technology
when the famous paper by Kao and Hockham,suggesting the use of
low-loss optical fibers for communication,appeared in 1966,6
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Text and translation
? The first low-loss (20dB/km) silica fiber was described in a
publication which appeared in October of 1970,The date of this
publication is sometimes cited as7 the beginning of the era of fiber
communication,Although this development did receive considerable
attention8 in the research community at the time,it was far from9
inevitable that a major industry would evolve,The 20dB/km loss
figure was still too high for long-hall telecommunication systems,The
fibers were fragile,and a way to protect them would have to be found,
There were no suitable light sources,Researchers did not know
whether field termination and splicing of optical cables would ever be
practical,Finally,there were serious doubts as to whether these
components could ever be produced10 economically enough for the
technology to play a major role in the marketplace,
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Text and translation
? Although the technological barriers appeared formidable,the
economic potential was very significant,As a consequence11,research
and development activity expanded rapidly,and a number of
important issues were resolved during the early 1970s,
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Text and translation
? During the middle and late 1970s,the rate of progress toward marketable
products accelerated as the emphasis shifted12 from research to engineering,
Fibers with losses approaching the Rayleigh limit of 2dB/km at a wavelength
of 0.8 μm,0.3dB/km at 1.3μm,and 0.15dB/km at 1.55μm,were produced in
the laboratory,Microbend13 loss problems were overcome through the use of
improved fiber coatings and cabling techniques,Rugged cables and
multifibre14 connectors were produced for field installation,Room
temperature threshold currents for commercial gallium aluminum arsenide
lasers operating in the 0.8 to 0.85 μm spectral region were reduced to the 20
to 30 mA range,and projected lifetimes in the 100,000 to 1,000,000 hour
range were claimed for both lasers and LEDs,Light sources and improved
photodetectors which operated near 1.3 μm were developed to take advantage
of the low fibre loss and dispersion in this "longer wavelength region",
Several major field trials were undertaken during this period,including
AT&T's Atlanta experiment and Chicago installation,and Japan's subscriber
access project,
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Text and translation
? Improvements in component performance,cost,and reliability by
1980 led to major commitments on the part of telephone companies,
Fiber soon became the preferred transmission medium for long-haul
trunks,Some early installations used 0.8 μm light sources and graded-
index multimode fiber,but by 1983,designers of intercity links were
thinking in terms of 1.3 μm,single-mode systems,The single-mode
fibre,used in conjunction with a 1.3 μm laser,provides a bandwidth
advantage which translates into15 increased repeater spacings for high
data rate systems,
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Text and translation
? Data rates for installed fiber optic systems have recently moved
into gigabit per second range,Such systems use the spectrally pure
distributed-feedback lasers to minimize fibre dispersion effects,Fibres
designed for low dispersion at 1.55 μm wavelength,which corresponds
to minimum fiber loss,are now commonly used in long distance
transmission16,The use of wavelength multiplexing to further increase
the fibre information capacity is becoming more widespread,
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Text and translation
? The potential of fibre optics in other areas is only beginning to be
realized,Fibre optic networks for computer systems and offices are
becoming more prominent,In the telephone system,the use of fibre
optics for interconnecting central offices within a metropolitan area
and for lower levels in the switching hierarchy is still increasing
rapidly,Fibre links to the home have been used in demonstration
projects,Many observers believe that national telephone systems will
eventually be upgraded to handle video bandwidths by using fibre
optics,These wideband subscriber loop systems would provide access
to services such as picturephone,video entertainment,Widespread
installation of these broadband services will become economically
feasible,
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Text and translation
? 与本单元课题有关的电信术语或用语 (22) 。
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Post-reading Activities
? i,Review the important expressions,phrases or sentences which were
learnt in the study of text by guiding the students through Exercises 1-
2 between Page 41 and Page 42 in class,
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Post-reading Activities
? ii,Ask the students to summarize the translation skills touched upon
in the study of the text,
? Possible answers,被动语态的译法和词类转化
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Further Development of the Theme-
related Specialized Knowledge
? 光纤通信基础教程
? http://www.ddvip.com/netapp/fddi/index1/index1.htm
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Assignments
? 1,Preview Unit 6
? 2,Do Exercises3-5 between Page 63 and Page 66
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本单元结束！
谢 谢！！
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?以下幻灯片为课文参考译文
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Text and translation
?光纤通信介绍
课 文
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Text and translation
? 80年代一项最重要的技术发展是光纤通信成为一个主要的国际性产
业 。 用光纤敷设总长度可以表明其发展程序 。 据估计, 到 1987年底
仅美国的光纤敷设总长将达 320万公里, 其中 90%以上是在 1982～
1987年间敷设并开通的, 而长途干线占主导地位, 数量约为光纤总
长的 95%。
课 文
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Text and translation
? 虽然现在人们对纤维光学的兴趣主要在于通信, 但早期发展纤维光
学的目的并不在此 。 50年代初研究人员制造出第一根具有包层玻璃
光纤时, 并不想用于通信而是想用它们传送内窥镜需要的成像光束 。
1966年 Kao和 Hockham发表了那篇著名的论文, 建议将低损耗光纤用
于通信, 此时纤维光学已发展为一项很实用的技术了 。
课 文
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Text and translation
? 1970年 10月, 第一根低损耗 (20 dB／ km)石英光纤问世了 。 有时将这
一日期作为光纤通信时代的开端 。 虽然这一成果当时在研究领域确
实引起了极大的关注, 但这种光纤距离通信所要求的条件还相差甚
远：每千米 20 dB的损耗对于长途通信系统仍然是太大了；光纤易断
裂, 必须寻找保护方法；没有合适的光源 。 研究人员不知道光缆的
终端和接头是否会发展到实用阶段, 至于生产这些器件是否在经济
上可行, 从而使之在市场上占有重要地位, 他们更是存有严重的疑
虑 。
课 文
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Text and translation
? 虽然技术障碍好像不可逾越, 但经济潜力却非常明显 。 正因为如此,
在 70年代早期研究和开发工作开展迅速, 一些重要问题得以解决 。
课 文
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Text and translation
? 70年代中后期, 由于发展重点由研究领域转入工程实用, 因而加速
发展了适应市场的产品 。 在实验室研制的光纤衰减值接近瑞利极限
值,0.8 um波长处为 2dB／ km,1.3 um波长处为 0.3 dB／ um和 1,55
um波长处为 0,15 dB／ um。 通过改进光纤外涂层方法和成缆技术,
克服了微弯损耗 。 生产了加强型光和多纤连接器用于室外作业 。 工
作在 O,8～ 0.85 pm波长区的商用镓铝砷激光器的室温阈值电流减少
到 20～ 30mA范围 。 据称, 激光器和发光管的设计寿命达 10万～ 100万
小时 。 开发了工作于 1.3／ um波长附近的光源和改进的光电检测器,
从而可以利用光纤在长波长区的低损耗和低色散特性 。 这一时期进
行的室外实验较重要的有 AT&T于 1976年在亚特兰大的实验, 1977年
在芝加哥的实验和 1977年日本的用户通路项目 。
课 文
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Text and translation
? 到了 80年代, 光纤器件在性能, 价格和可靠性方面的改善使众多电
话公司受益匪浅 。 光纤很快成为长途干线的首选传输媒质 。 一些早
期敷设的光纤线路采用 0.8／ um光源和渐变折射率多模光纤, 但到
1983年, 城市间线路的设计者们就考虑使用 1.3／ um单模光纤系统了 。
单模光纤与 1.3 um激光器连接, 可以提供宽带特性, 增加了高速率
系统的中继距离 。
课 文
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Text and translation
? 最近敷设的光纤系统的数据速率已移至每秒吉比特范围 。 这种系统
采用光谱纯的分布反馈激光器, 将光纤色散效应减至最小 。 在
1.55um波长上设计的低色散光纤, 相应地具有低损耗特性, 目前广
泛用于长途通信 。 为进一步增加光纤的信息容量, 逐渐广泛采用波
分复用方法 。
课 文
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Text and translation
? 人们对于光纤在其他领域的潜力刚刚开始认识 。 用于计算机系统和
办公室的光纤网络逐渐变得更加重要 。 在电话系统中, 光纤在主要
城市地区中心交换局间互联和低级交换中的使用继续迅速增加 。 入
户光缆已经有了示范工程 。 许多观察家相信, 全国电话系统将使用
光纤传输视频宽带信号而逐渐升级 。 这些宽带用户环路系统将为可
视电话, 视频娱乐节目等业务提供通路 。 宽带业务广泛使用光纤将
会变得经济可行 。
课 文
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While-reading Activities /
Key language points
? 1,One indication of the extent of this development is the total length
of installed fiber,…,
? 翻译技巧：词类转换
? 英语中大量由动词派生的名词往往可转译为汉语动词, 例如此句
可译为, 用光纤敷设总长度可以 表明 其发展程度, 。
? 更多译例,
? ① Rockets have found application for the exploration of the
universe,
? 火箭已经 用来探索 宇宙 。
? ② Integrated circuits are fairly recent development,
? 集成电路是近年来才 发展起来 的 。
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While-reading Activities /
Key language points
? 2,place… in service, put … into use (投入使用 )
? eg,The system will be placed in service in two hours
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While-reading Activities /
Key language points
? 3,account for,make up (占,.)
? eg,The users of China Mobile Corporation account for more than
70% of the total users of mobile communication in China
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While-reading Activities /
Key language points
? 4,… this was not the case during the early days of the technology,
?,this was not the case”意为, This is not the fact”（ 当时的实际情况
并非如此 ） 。
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While-reading Activities /
Key language points
? 5,well-established,本文中可理解为, 发展得相当成熟的, 。
? 构词法：副词 -过去分词构成形容词 。
? 更多词例,well-informed（ 消息灵通的 ）
? poorly-educated (教育程度低的 )
? newly-built (新建的 )
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While-reading Activities /
Key language points
? 6,… when the famous paper by Kao and Hockham,suggesting the use
of low-loss optical fibers for communication,appeared in 1966,
? 句子结构分析,
? 这是一个时间状语从句, 从句中主语和谓语被现在分词短语割裂 。
? 主语,the famous paper
? 谓语,appeared
? 定语：介词短语, by Kao and Hockham”和, suggesting the use of
low-loss optical fibers for communication” 现在分词短语共同修饰主
语, the famous paper”
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While-reading Activities /
Key language points
? 7,cite… as…, consider… to be,regard… as (把 … 当作 … )
? eg,The experiment was cited as an epoch-making event,
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While-reading Activities /
Key language points
? 8,receive attention,grab or capture attention (引起关注 )
? eg,Their paper on optical fiber communication received the
worldwide attention then,
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While-reading Activities /
Key language points
? 9,far from,远离,远非,完全不,非但不
? eg,The performance of the system is far from satisfactory,
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While-reading Activities /
Key language points
10,Finally,there were serious doubts as to whether these components
could ever be produced
这一句中的 as to是个短语, 与 as regards相同, 意为, 至于 …,,它们经
常与 doubt,agree等词连用, 后跟 whether,what,how等词引出的从句 。
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While-reading Activities /
Key language points
? 11,as a consequence,as a result (结果 )
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While-reading Activities /
Key language points
? 12,shift… (from… to..),move or transfer from one place or position to
another(把,.由 … 转移到 … ),
? eg,The focus of our task should be shifted from cities to rural areas,
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While-reading Activities /
Key language points
? 13,micro-
? pref,
? 1) small(小的,微型的 ),
? eg,microcircuit(微型电路 ),microprocessor(微处理器 ),microwave
（ 微波 ）,microprogram（ 微程序 ）, microcode（ 微代码 ）
? 2） one-millionth (10-6) 百方分之一的 (10-6),
? microampere (微安 （ 培 ） ),microvolt(微伏 )
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While-reading Activities /
Key language points
? 14,multi-
? pref,many; much; multiple,more than one or two
? eg,multi-access telephone service (多路存取电话业务 )
? multi-alternate routing (多通路方案 multiconductor (多对芯线 )
? multilink（ 多链路 ） multi-frequency pulsing（ 多频发送信号 ）
? multi-drop line （ 多点线路 ）
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While-reading Activities /
Key language points
? 15,translate into…, be changed or transformed in effect(转化成 … )
? eg,Today's low inflation and steady growth in household income
translate into more purchasing power,
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While-reading Activities /
Key language points
? 16,Fibres designed for low dispersion at 1.55 μm wavelength,which
corresponds to minimum fiber loss,are now commonly used in long
distance transmission,
? 句子结构分析,
? 此句中主语和谓语被过去分词短语和非限定性定语从句割裂 。
? 主语,fibres
? 谓语,are
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While-reading Activities /
Key language points
? 定语：过去分词短语, designed for low dispersion at 1.55 μm
wavelength”和非限定性定语从句,,which corresponds to minimum
fiber loss”作定语共同修饰主语, the famous paper”。
? be designed for /to do,为 … 而预定, 设计 。
? eg,The sophisticated system is designed to detect the change of
global climate,
上 一 页
四川邮电职业技术学院 52
While-reading Activities /
Key language points
? 22,与本单元课题有关的电信术语或用语,
? long-haul trunk 长途干线 imaging bundles 成像光束
? fiber optics 光纤学 optical cables 光缆
? microbend loss 微弯损耗 multi-fibre connectors 多纤连接器
? threshold currents 阈值电流
? projected lifetimes 设计 （ 使用 ） 寿命
? light sources 光源 photodetector 光电检测器
? wavelength 波长 video bandwidth 视频带宽
下 一 页
四川邮电职业技术学院 53
While-reading Activities /
Key language points
? broadband services 宽带业务 picturephone 可视电话
? repeater spacing 中继距离 wavelength multiplexing 波分复用
? LED (light-emitting diode) 发光二级管
? wideband subscriber loop system 宽带用户环路系统
? graded-index multimode fibre 渐变多模光纤
? distributed-feedback laser 分布反馈激光器
? fiber dispersion effects 光纤色散效应
上 一 页
Introduction to Optical
Fibre Communication
四川邮电职业技术学院 2
Contents
? Teaching Objectives
? Revision
? Pre-reading Activities
? While-reading Activities
?New words and phrases
?Text organization
?Text and translation
? Post-reading Activities
? Further Development of the Theme-related
Specialized Knowledge
? Assignments
四川邮电职业技术学院 3
Teaching Objectives
? 1.to know the historical development of optical fiber communication
and its latest development and future
? 2,to understand the main idea and organization of the text;
? 3.to master some important new words,phrases and their usages,
especially the theme-related telecom terms and expressions in the text;
返 回
四川邮电职业技术学院 4
Revision
? Teacher uses the following exercise to help the students to revise the
important expressions or phrases or sentences which were learnt in
the study of last unit,
? Teacher, When I say a phrase or an expression in Chinese,you
respond by giving an English equivalent your learnt in the study of
Unit 4 Internet,
? Teacher ( Chinese ) Students ( English)
返 回 下 一 页
四川邮电职业技术学院 5
Revision
? 网络资源 network resource
? 信息服务 information service
? 远程终端 remote terminal
? 电子邮件 electronic mail
? 无线信道 wireless channel
? 搜索工具 searching tool
? 用户界面 user interface
? 文本信息 textual message
? 超文本协议 hypertext protocol
返 回 上 一 页
四川邮电职业技术学院 6
Pre-reading Activities
? 1,Ask the Ss the following two questions related to the theme of
the text,
? 1) You have exposed yourselves to optical fiber communication in
the study of communication technology-related courses,Any one
would like to define it in your own words?
? Possible Answer,Optical fiber communication is referred to as the
communication with laser as the light source and optical fiber as the
transmission medium,
? 2) Who can tell us its remarkable characteristics?
? Possible Answer,Optical fiber communication is characterized by
large transmission capacity and sound performance anti-
electromagnetic interference
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四川邮电职业技术学院 7
While-reading Activities / New
words and phrases
? accelerate ［ ?ｋ 'ｓｅｌ ?ｒｅｉｔ］ vt.; vi,加速
? account ［ ??ｋ αｕｎｔ］ n,帐目，报道；说明
? barrier ［ 'ｂ ?ｒｉ ?］ n,隔板，障碍，界限
? breakage ［ 'ｂｒｅｉｋｉ ?］ n,破坏，损耗量
? broadband n,宽频带，宽波段
? bundle ［ ?ｂ ?ｎｄｌ］ n,捆，束
? cite ［ｓａｉｔ］ vt,引用，举 (例 )
? clad ［ｋｌ ?ｄ］ a,穿衣的,(金属 )包层
? commitment ［ｋ ?'ｍｉｔｍ ?ｎｔ］ n,作为，赞助，委托
? community ［ｋ ?'ｍｊｕ,ｎｉｔｙ］ n,团体，社会
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四川邮电职业技术学院 8
While-reading Activities / New
words and phrases
? dominate ［ 'ｄ ?ｍｉｎｅｉｔ］ vt,支配，统治；处于支配地位
? dopant ［ 'ｄａｕｐａｎｔ］ n,掺杂物，掺杂剂
? emerge ［ｉ‘ｍ ?,?］ vi,出现，形成，浮现
? emergence ［ｉ 'ｍ ?,??ｎｓ］ n,浮现，出现
? endoscopy ［ｅｎ 'ｄ ?ｓｋ ?ｐｉ］ n,内窥镜
? entertainment ［ｅｎｔ ?'ｔｅｉｎｍ ?ｎｔ］ n,招待，娱乐
? evolve ［ｉ 'ｖ ?ｌｖ］ vt,使发展，推论；进展，发展，进化
? favorable ［ 'ｆｅｉｖ ?ｒ ?ｂｌ］ a,顺利的，有利的，称赞的
? feasible ［‘ｆｉ,ｚ ?ｂｌ］ a,可实行的，行得通的，可能的
? purification ［ｐｊｕ ?ｒｆ ?'ｋｅｉ ??ｎ］ n,提纯，净化
? radiance ［ 'ｒｅｉｄｉ ?ｎｓ］ n,发光，容光焕发
? rationale ［ｒ ??ｉ ?'ｎ α:ｌｉ］ n,(某事物的 )基本理由，理论基础
上 一 页 返 回
四川邮电职业技术学院 9
While-reading Activities / Text
organization
? Text organization
? 1,Ss read the text and point out the main idea of the text,
? The main idea,The text mainly discusses the historical development
of optical fiber communication and its latest development,
? 2,Ss make an analysis of the organization of the text,
? The text may be divided into four major sections,
? Section1 (Lines1-8),introduction of the extent of the recent
development of optical fiber communication through the total length
of installed optical fiber;
? Section2 (Lines9-56),the historical development of optical fiber
communication;
? Section3(Lines57-74),the latest development and future of optical
fiber communication,
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四川邮电职业技术学院 10
Text and translation
?Introduction to Optical Fibre Communication
翻 译 下 一 页 返 回
四川邮电职业技术学院 11
Text and translation
? One of the most important technological developments during the
1980s has been the emergence of optical fiber communication as a
major international industry,One indication of the extent of this
development is the total length of installed fiber1,which was
estimated to be 3.2 million kilometers in the U.S,alone by the end of
1987,Over 90% of this fiber was placed in service2 during the time
period of 1982~1987,Long-haul trunk installations have been
dominated,accounting for3 about 95% of the fiber in the U.S,
翻 译 下 一 页 上 一 页 返 回
四川邮电职业技术学院 12
Text and translation
? Although telecommunication is the rationale for most of the current
interest in fiber optics,this was not the case4 during the early days of
the technology,The researchers who produced the first clad glass
optical fibersin the early 1950s were not thinking of using them for
communications; they wanted to make imaging bundles for endoscopy,
Fiber optics was already a well-established5 commercial technology
when the famous paper by Kao and Hockham,suggesting the use of
low-loss optical fibers for communication,appeared in 1966,6
翻 译 下 一 页 上 一 页 返 回
四川邮电职业技术学院 13
Text and translation
? The first low-loss (20dB/km) silica fiber was described in a
publication which appeared in October of 1970,The date of this
publication is sometimes cited as7 the beginning of the era of fiber
communication,Although this development did receive considerable
attention8 in the research community at the time,it was far from9
inevitable that a major industry would evolve,The 20dB/km loss
figure was still too high for long-hall telecommunication systems,The
fibers were fragile,and a way to protect them would have to be found,
There were no suitable light sources,Researchers did not know
whether field termination and splicing of optical cables would ever be
practical,Finally,there were serious doubts as to whether these
components could ever be produced10 economically enough for the
technology to play a major role in the marketplace,
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四川邮电职业技术学院 14
Text and translation
? Although the technological barriers appeared formidable,the
economic potential was very significant,As a consequence11,research
and development activity expanded rapidly,and a number of
important issues were resolved during the early 1970s,
翻 译 下 一 页 上 一 页 返 回
四川邮电职业技术学院 15
Text and translation
? During the middle and late 1970s,the rate of progress toward marketable
products accelerated as the emphasis shifted12 from research to engineering,
Fibers with losses approaching the Rayleigh limit of 2dB/km at a wavelength
of 0.8 μm,0.3dB/km at 1.3μm,and 0.15dB/km at 1.55μm,were produced in
the laboratory,Microbend13 loss problems were overcome through the use of
improved fiber coatings and cabling techniques,Rugged cables and
multifibre14 connectors were produced for field installation,Room
temperature threshold currents for commercial gallium aluminum arsenide
lasers operating in the 0.8 to 0.85 μm spectral region were reduced to the 20
to 30 mA range,and projected lifetimes in the 100,000 to 1,000,000 hour
range were claimed for both lasers and LEDs,Light sources and improved
photodetectors which operated near 1.3 μm were developed to take advantage
of the low fibre loss and dispersion in this "longer wavelength region",
Several major field trials were undertaken during this period,including
AT&T's Atlanta experiment and Chicago installation,and Japan's subscriber
access project,
翻 译 下 一 页 上 一 页 返 回
四川邮电职业技术学院 16
Text and translation
? Improvements in component performance,cost,and reliability by
1980 led to major commitments on the part of telephone companies,
Fiber soon became the preferred transmission medium for long-haul
trunks,Some early installations used 0.8 μm light sources and graded-
index multimode fiber,but by 1983,designers of intercity links were
thinking in terms of 1.3 μm,single-mode systems,The single-mode
fibre,used in conjunction with a 1.3 μm laser,provides a bandwidth
advantage which translates into15 increased repeater spacings for high
data rate systems,
翻 译 下 一 页 上 一 页 返 回
四川邮电职业技术学院 17
Text and translation
? Data rates for installed fiber optic systems have recently moved
into gigabit per second range,Such systems use the spectrally pure
distributed-feedback lasers to minimize fibre dispersion effects,Fibres
designed for low dispersion at 1.55 μm wavelength,which corresponds
to minimum fiber loss,are now commonly used in long distance
transmission16,The use of wavelength multiplexing to further increase
the fibre information capacity is becoming more widespread,
翻 译 下 一 页 上 一 页 返 回
四川邮电职业技术学院 18
Text and translation
? The potential of fibre optics in other areas is only beginning to be
realized,Fibre optic networks for computer systems and offices are
becoming more prominent,In the telephone system,the use of fibre
optics for interconnecting central offices within a metropolitan area
and for lower levels in the switching hierarchy is still increasing
rapidly,Fibre links to the home have been used in demonstration
projects,Many observers believe that national telephone systems will
eventually be upgraded to handle video bandwidths by using fibre
optics,These wideband subscriber loop systems would provide access
to services such as picturephone,video entertainment,Widespread
installation of these broadband services will become economically
feasible,
翻 译 下 一 页 上 一 页 返 回
四川邮电职业技术学院 19
Text and translation
? 与本单元课题有关的电信术语或用语 (22) 。
上 一 页 返 回
四川邮电职业技术学院 20
Post-reading Activities
? i,Review the important expressions,phrases or sentences which were
learnt in the study of text by guiding the students through Exercises 1-
2 between Page 41 and Page 42 in class,
下 一 页
四川邮电职业技术学院 21
Post-reading Activities
? ii,Ask the students to summarize the translation skills touched upon
in the study of the text,
? Possible answers,被动语态的译法和词类转化
上 一 页 返 回
四川邮电职业技术学院 22
Further Development of the Theme-
related Specialized Knowledge
? 光纤通信基础教程
? http://www.ddvip.com/netapp/fddi/index1/index1.htm
返 回
四川邮电职业技术学院 23
Assignments
? 1,Preview Unit 6
? 2,Do Exercises3-5 between Page 63 and Page 66
返 回
四川邮电职业技术学院 24
本单元结束！
谢 谢！！
四川邮电职业技术学院 25
?以下幻灯片为课文参考译文
四川邮电职业技术学院 26
Text and translation
?光纤通信介绍
课 文
四川邮电职业技术学院 27
Text and translation
? 80年代一项最重要的技术发展是光纤通信成为一个主要的国际性产
业 。 用光纤敷设总长度可以表明其发展程序 。 据估计, 到 1987年底
仅美国的光纤敷设总长将达 320万公里, 其中 90%以上是在 1982～
1987年间敷设并开通的, 而长途干线占主导地位, 数量约为光纤总
长的 95%。
课 文
四川邮电职业技术学院 28
Text and translation
? 虽然现在人们对纤维光学的兴趣主要在于通信, 但早期发展纤维光
学的目的并不在此 。 50年代初研究人员制造出第一根具有包层玻璃
光纤时, 并不想用于通信而是想用它们传送内窥镜需要的成像光束 。
1966年 Kao和 Hockham发表了那篇著名的论文, 建议将低损耗光纤用
于通信, 此时纤维光学已发展为一项很实用的技术了 。
课 文
四川邮电职业技术学院 29
Text and translation
? 1970年 10月, 第一根低损耗 (20 dB／ km)石英光纤问世了 。 有时将这
一日期作为光纤通信时代的开端 。 虽然这一成果当时在研究领域确
实引起了极大的关注, 但这种光纤距离通信所要求的条件还相差甚
远：每千米 20 dB的损耗对于长途通信系统仍然是太大了；光纤易断
裂, 必须寻找保护方法；没有合适的光源 。 研究人员不知道光缆的
终端和接头是否会发展到实用阶段, 至于生产这些器件是否在经济
上可行, 从而使之在市场上占有重要地位, 他们更是存有严重的疑
虑 。
课 文
四川邮电职业技术学院 30
Text and translation
? 虽然技术障碍好像不可逾越, 但经济潜力却非常明显 。 正因为如此,
在 70年代早期研究和开发工作开展迅速, 一些重要问题得以解决 。
课 文
四川邮电职业技术学院 31
Text and translation
? 70年代中后期, 由于发展重点由研究领域转入工程实用, 因而加速
发展了适应市场的产品 。 在实验室研制的光纤衰减值接近瑞利极限
值,0.8 um波长处为 2dB／ km,1.3 um波长处为 0.3 dB／ um和 1,55
um波长处为 0,15 dB／ um。 通过改进光纤外涂层方法和成缆技术,
克服了微弯损耗 。 生产了加强型光和多纤连接器用于室外作业 。 工
作在 O,8～ 0.85 pm波长区的商用镓铝砷激光器的室温阈值电流减少
到 20～ 30mA范围 。 据称, 激光器和发光管的设计寿命达 10万～ 100万
小时 。 开发了工作于 1.3／ um波长附近的光源和改进的光电检测器,
从而可以利用光纤在长波长区的低损耗和低色散特性 。 这一时期进
行的室外实验较重要的有 AT&T于 1976年在亚特兰大的实验, 1977年
在芝加哥的实验和 1977年日本的用户通路项目 。
课 文
四川邮电职业技术学院 32
Text and translation
? 到了 80年代, 光纤器件在性能, 价格和可靠性方面的改善使众多电
话公司受益匪浅 。 光纤很快成为长途干线的首选传输媒质 。 一些早
期敷设的光纤线路采用 0.8／ um光源和渐变折射率多模光纤, 但到
1983年, 城市间线路的设计者们就考虑使用 1.3／ um单模光纤系统了 。
单模光纤与 1.3 um激光器连接, 可以提供宽带特性, 增加了高速率
系统的中继距离 。
课 文
四川邮电职业技术学院 33
Text and translation
? 最近敷设的光纤系统的数据速率已移至每秒吉比特范围 。 这种系统
采用光谱纯的分布反馈激光器, 将光纤色散效应减至最小 。 在
1.55um波长上设计的低色散光纤, 相应地具有低损耗特性, 目前广
泛用于长途通信 。 为进一步增加光纤的信息容量, 逐渐广泛采用波
分复用方法 。
课 文
四川邮电职业技术学院 34
Text and translation
? 人们对于光纤在其他领域的潜力刚刚开始认识 。 用于计算机系统和
办公室的光纤网络逐渐变得更加重要 。 在电话系统中, 光纤在主要
城市地区中心交换局间互联和低级交换中的使用继续迅速增加 。 入
户光缆已经有了示范工程 。 许多观察家相信, 全国电话系统将使用
光纤传输视频宽带信号而逐渐升级 。 这些宽带用户环路系统将为可
视电话, 视频娱乐节目等业务提供通路 。 宽带业务广泛使用光纤将
会变得经济可行 。
课 文
四川邮电职业技术学院 35
While-reading Activities /
Key language points
? 1,One indication of the extent of this development is the total length
of installed fiber,…,
? 翻译技巧：词类转换
? 英语中大量由动词派生的名词往往可转译为汉语动词, 例如此句
可译为, 用光纤敷设总长度可以 表明 其发展程度, 。
? 更多译例,
? ① Rockets have found application for the exploration of the
universe,
? 火箭已经 用来探索 宇宙 。
? ② Integrated circuits are fairly recent development,
? 集成电路是近年来才 发展起来 的 。
四川邮电职业技术学院 36
While-reading Activities /
Key language points
? 2,place… in service, put … into use (投入使用 )
? eg,The system will be placed in service in two hours
四川邮电职业技术学院 37
While-reading Activities /
Key language points
? 3,account for,make up (占,.)
? eg,The users of China Mobile Corporation account for more than
70% of the total users of mobile communication in China
四川邮电职业技术学院 38
While-reading Activities /
Key language points
? 4,… this was not the case during the early days of the technology,
?,this was not the case”意为, This is not the fact”（ 当时的实际情况
并非如此 ） 。
四川邮电职业技术学院 39
While-reading Activities /
Key language points
? 5,well-established,本文中可理解为, 发展得相当成熟的, 。
? 构词法：副词 -过去分词构成形容词 。
? 更多词例,well-informed（ 消息灵通的 ）
? poorly-educated (教育程度低的 )
? newly-built (新建的 )
四川邮电职业技术学院 40
While-reading Activities /
Key language points
? 6,… when the famous paper by Kao and Hockham,suggesting the use
of low-loss optical fibers for communication,appeared in 1966,
? 句子结构分析,
? 这是一个时间状语从句, 从句中主语和谓语被现在分词短语割裂 。
? 主语,the famous paper
? 谓语,appeared
? 定语：介词短语, by Kao and Hockham”和, suggesting the use of
low-loss optical fibers for communication” 现在分词短语共同修饰主
语, the famous paper”
四川邮电职业技术学院 41
While-reading Activities /
Key language points
? 7,cite… as…, consider… to be,regard… as (把 … 当作 … )
? eg,The experiment was cited as an epoch-making event,
四川邮电职业技术学院 42
While-reading Activities /
Key language points
? 8,receive attention,grab or capture attention (引起关注 )
? eg,Their paper on optical fiber communication received the
worldwide attention then,
四川邮电职业技术学院 43
While-reading Activities /
Key language points
? 9,far from,远离,远非,完全不,非但不
? eg,The performance of the system is far from satisfactory,
四川邮电职业技术学院 44
While-reading Activities /
Key language points
10,Finally,there were serious doubts as to whether these components
could ever be produced
这一句中的 as to是个短语, 与 as regards相同, 意为, 至于 …,,它们经
常与 doubt,agree等词连用, 后跟 whether,what,how等词引出的从句 。
四川邮电职业技术学院 45
While-reading Activities /
Key language points
? 11,as a consequence,as a result (结果 )
四川邮电职业技术学院 46
While-reading Activities /
Key language points
? 12,shift… (from… to..),move or transfer from one place or position to
another(把,.由 … 转移到 … ),
? eg,The focus of our task should be shifted from cities to rural areas,
四川邮电职业技术学院 47
While-reading Activities /
Key language points
? 13,micro-
? pref,
? 1) small(小的,微型的 ),
? eg,microcircuit(微型电路 ),microprocessor(微处理器 ),microwave
（ 微波 ）,microprogram（ 微程序 ）, microcode（ 微代码 ）
? 2） one-millionth (10-6) 百方分之一的 (10-6),
? microampere (微安 （ 培 ） ),microvolt(微伏 )
四川邮电职业技术学院 48
While-reading Activities /
Key language points
? 14,multi-
? pref,many; much; multiple,more than one or two
? eg,multi-access telephone service (多路存取电话业务 )
? multi-alternate routing (多通路方案 multiconductor (多对芯线 )
? multilink（ 多链路 ） multi-frequency pulsing（ 多频发送信号 ）
? multi-drop line （ 多点线路 ）
四川邮电职业技术学院 49
While-reading Activities /
Key language points
? 15,translate into…, be changed or transformed in effect(转化成 … )
? eg,Today's low inflation and steady growth in household income
translate into more purchasing power,
四川邮电职业技术学院 50
While-reading Activities /
Key language points
? 16,Fibres designed for low dispersion at 1.55 μm wavelength,which
corresponds to minimum fiber loss,are now commonly used in long
distance transmission,
? 句子结构分析,
? 此句中主语和谓语被过去分词短语和非限定性定语从句割裂 。
? 主语,fibres
? 谓语,are
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四川邮电职业技术学院 51
While-reading Activities /
Key language points
? 定语：过去分词短语, designed for low dispersion at 1.55 μm
wavelength”和非限定性定语从句,,which corresponds to minimum
fiber loss”作定语共同修饰主语, the famous paper”。
? be designed for /to do,为 … 而预定, 设计 。
? eg,The sophisticated system is designed to detect the change of
global climate,
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四川邮电职业技术学院 52
While-reading Activities /
Key language points
? 22,与本单元课题有关的电信术语或用语,
? long-haul trunk 长途干线 imaging bundles 成像光束
? fiber optics 光纤学 optical cables 光缆
? microbend loss 微弯损耗 multi-fibre connectors 多纤连接器
? threshold currents 阈值电流
? projected lifetimes 设计 （ 使用 ） 寿命
? light sources 光源 photodetector 光电检测器
? wavelength 波长 video bandwidth 视频带宽
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四川邮电职业技术学院 53
While-reading Activities /
Key language points
? broadband services 宽带业务 picturephone 可视电话
? repeater spacing 中继距离 wavelength multiplexing 波分复用
? LED (light-emitting diode) 发光二级管
? wideband subscriber loop system 宽带用户环路系统
? graded-index multimode fibre 渐变多模光纤
? distributed-feedback laser 分布反馈激光器
? fiber dispersion effects 光纤色散效应
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