中山復(fù)試專業(yè)英語wdm

1、專 業(yè) 英 語 Specialized English Unit 9：第二部分 通信技術(shù) WDM （Wavelength Division Multiplexing）波分復(fù)用Specialized English for Communication Engineering Wavelength Division Multiplexing (波分復(fù)用):相關(guān)背景知識(shí)l0數(shù)據(jù) 話音單波長的系統(tǒng)WDMl0數(shù)據(jù) 話音l1lnl2 .波分復(fù)用系統(tǒng)在一根光纖中同時(shí)傳輸多波長光信號(hào)的一種技術(shù)Optical beams with different wavelengths propagate without

2、affecting one another, so several channels of information (each having a different carrier wavelength) can be transmitted simultaneously over a single fiber. This scheme, called wavelength-division multiplexing (WDM), increases the information-carrying capacity of a fiber.合波器分波器 1 2 3n 1 2 3n波分復(fù)用的原理

3、NEW WORDS AND PHRASES visionary n. 幻想家，夢(mèng)想家significant adj. 重大的，效果顯著的span n. 跨度, 跨距, 范圍 v. 橫越equivalent adj. 相等的, 相當(dāng)?shù)? 同意義的 n. 等價(jià)物, 相等物video n. (adj.) 電視（的），視頻（的），影像（的）approximate adj. 近似的，大概的 adv. ly boost v. 推進(jìn)，增加，提高eliminate v. 排除，淘汰considerable adj. 相當(dāng)大的，相當(dāng)多的simultaneous adj. 同時(shí)發(fā)生的，同時(shí)存在的，同時(shí)的expon

4、ential adj. 指數(shù)的，冪的Specialized English for Communication Engineering Specialized English on Communication Engineering Even visionaries such as Albert Einstein and Isaac Newton, who contributed significantly to our understanding of the properties of light and its fundamental importance, would not like

5、ly imagine the communications networks of today. visionary ：空想家, 夢(mèng)想者, 好幻想的人fundamental ：基礎(chǔ)的, 基本的愛因斯坦和牛頓在我們對(duì)光特性的了解及其基本重要性方面做出了重大的貢獻(xiàn)，即使是這樣富于幻想的人也不大可能想象的到今天通信網(wǎng)絡(luò)發(fā)展的程度。 Specialized English on Communication Engineering Highways of light span the globe, transmitting massive amounts of information in the tw

6、inkling of an eye. The equivalents of millions of telephone calls are transmitted on a single fiber, thinner than a human hair. Astounding as these advances may seem, we are only at the beginning of what is possible . massive ：大量的；astounding ：令人吃驚的 光的高速公路跨越全球，眨眼之間傳輸巨量的信息。這等于數(shù)百萬電話的通信量通過比人的頭發(fā)還細(xì)的光纖進(jìn)行傳輸

7、。這些成就似乎使人很吃驚，但我們只是處于可能會(huì)產(chǎn)生更大成就的開始。Specialized English on Communication Engineering The current explosion of traffic in the worldwide networks is ample evidence of the speed with which we are adopting new communications technologies. The growth of wireless systems and the Internet are well-documented

8、phenomena. explosion ：爆發(fā)，激增traffic ：交通, 通行, 運(yùn)輸, 貿(mào)易,交易, (電信)業(yè)務(wù) wireless systems ：無線系統(tǒng)目前全球網(wǎng)絡(luò)業(yè)務(wù)的激增充分地表明了我們采用新的通信技術(shù)的速度。無線系統(tǒng)和因特網(wǎng)的發(fā)展就是很好的證明。Specialized English on Communication Engineering No matter what application it is that is generating traffic, most of this traffic will be carried by the unifying opt

9、ical layer. 不管是哪一種產(chǎn)生業(yè)務(wù)的應(yīng)用，大多數(shù)這種業(yè)務(wù)將會(huì)由統(tǒng)一的光層進(jìn)行傳送。 Specialized English on Communication Engineering For this reason, the growth of various applications such as telephony (whether cellular or fixed), Internet, video transmission, computer communication and database access leads directly to an increase in

10、 the demand placed on the optical network. telephony ：電話學(xué), 電話, 電話通訊由于這一原因，各種應(yīng)用的增長，如電話（移動(dòng)或固定）、因特網(wǎng)、視頻傳輸、計(jì)算機(jī)通信和數(shù)據(jù)庫接入直接導(dǎo)致對(duì)光網(wǎng)絡(luò)持續(xù)增長的需要。 Specialized English on Communication Engineering It is very likely that the optical network will be used to convey large amounts of video information in the future.video

11、information ：視頻信息很有可能將來光網(wǎng)絡(luò)會(huì)用來傳送大量的視頻信息。Specialized English on Communication Engineering The most striking recent advances in optical networking have taken place in the field of Wavelength Division Multiplexing (WDM). Wavelength Division Multiplexing ：波分復(fù)用（WDM）進(jìn)來光網(wǎng)絡(luò)方面最引人注目的進(jìn)展出現(xiàn)在波分復(fù)用(WDM)方面。 Specializ

12、ed English on Communication Engineering These advances have benefited both terrestrial and submarine systems, increased available capacities by several orders of magnitude and correspondingly, reduced costs.terrestrial ：陸地的，地面的submarine ：海底的，水下的這些進(jìn)展對(duì)地面通信系統(tǒng)和海底通信系統(tǒng)都帶來了好處，將可用的容量增加了幾個(gè)數(shù)量級(jí)，而相應(yīng)地減少了費(fèi)用。 Spec

13、ialized English on Communication Engineering Until quite recently, it was possible to send only one wavelength, or color, of light along each fiber. A lot of effort has therefore been concentrated in maximizing the amount of information that can be transmitted using a single wavelength. concentrate

14、：集中，匯聚目前，在一根光纖上只能發(fā)送單波長或單顏色的光。因此，大量的努力集中于使用單個(gè)波長來傳輸最大量的信息。 Specialized English on Communication Engineering Commercial systems will soon be able to carry 40 Gbit/s on a single wavelength, while in the labs 320 Gbit/s systems have already been demonstrated.Commercial systems ： 商用系統(tǒng)商用系統(tǒng)很快就能夠在單個(gè)波長上傳輸40 G

15、bit/s 的信息，而在實(shí)驗(yàn)室，已經(jīng)演示了傳輸320 Gbit/s 的系統(tǒng)。 Specialized English on Communication Engineering WDM, on the other hand, makes it possible to transmit a large number of wavelengths using the same fiber, effectively sending a “rainbow” of colors, where there was only one color before. rainbow ：彩虹另一方面，WDM使得使用同

16、樣的光纖傳輸很多波長成為可能，可以有效的發(fā)送顏色的“彩虹”，而在以前只有一種顏色。Specialized English on Communication Engineering Already today, commercially available systems can transmit 400 Gbit/s of information on a single fiber. That is equivalent to transmitting approximately 200 feature-length films per second. approximately ：近似地,

17、大約今天商用系統(tǒng)可以在一根光纖上傳輸400 Gbit/s 的信息。這大約等效于每秒傳輸200部故事片。 Specialized English on Communication Engineering Recently, a team of researchers from Bell Labs demonstrated long-distance, error-free transmission of 3.28 Tbit/s over a single optical fiber.error-free：無誤碼的最近，貝爾實(shí)驗(yàn)室的一個(gè)研究隊(duì)伍展示了在一根光纖上速率高達(dá)3.28 Tbit/s 的長

18、途、無誤碼的傳輸系統(tǒng)。 Specialized English on Communication Engineering The major advance that has led to the WDM revolution has been the invention of the Optical Amplifier (OA). Optical Amplifier:光放大器（OA）導(dǎo)致WDM革命的主要進(jìn)展是光放大器（OA）的發(fā)明。 Specialized English on Communication Engineering Before the invention of the OA,

19、 after having traveled down a fiber for some distance, each individual wavelength had to be converted into the electronic form, then back into optical form and then transmitted into the next span of fiber. 在光放大器（OA）發(fā)明之前，單個(gè)波長在經(jīng)過光纖傳輸一定距離之后，必須轉(zhuǎn)換成電信號(hào)的形式，然后再變換回到光信號(hào)形式并通過下一段光纖傳輸。 Specialized English on Com

20、munication Engineering This was relatively expensive, since the optical components involved are highly specialized devices. The OA, however, can boost the signal power of all wavelengths in the fiber, thus eliminating the need for separate regenerators, and allowing many wavelengths to share the sam

21、e fiber.specialized：專用的，專門的boost ：推進(jìn)，增加，增強(qiáng)，放大regenerator：再生器這樣就使得費(fèi)用比較昂貴，因?yàn)樗婕暗墓馄骷歉叨葘Ｓ玫钠骷?。然而，光放大器（OA）可以放大光纖中所有波長的信號(hào)功率，這樣就不需要不同的再生器并允許許多波長共用同樣的光纖。 Specialized English on Communication Engineering Advances in optical amplifier design have been considerable. First, the operating window has expended fro

22、m 12 nm, in the first generation, to about 80 nm today. This allows the OA to amplify more signals simultaneously. considerable ：重要的，可觀的，相當(dāng)大的operating window ：工作窗口simultaneously ：同時(shí)地光放大器設(shè)計(jì)方面的進(jìn)展是相當(dāng)可觀的。首先，光纖的工作窗口已由第一代的 12 nm擴(kuò)展到今天的80 nm。這使光放大器可以同時(shí)放大更多的信號(hào)。Specialized English on Communication Engineering

23、 Second, the development of gain equalization techniques has enabled a much flatter response and allows a number of these amplifiers to be connected in series. There have also been advances in the fibers themselves. gain equalization techniques ：增益均衡技術(shù)flatter response ：平坦響應(yīng)in series ：連續(xù)地, 串聯(lián)第二，增益均衡技

24、術(shù)的發(fā)展可以產(chǎn)生更平坦的信號(hào)響應(yīng)，并允許這樣的一些放大器以串聯(lián)的形式連接。光纖本身也有了進(jìn)展。Specialized English on Communication Engineering In the early days of optical systems, optical fibers were not built for multi-wavelength transmission. Todays fibers, on the other hand, are designed to have wide transmission windows and are optimized fo

25、r high-capacity, multiple-wave-length transmission.multi-wavelength transmission ：多波長傳輸transmission windows ：傳輸窗口high-capacity ：大容量在早期的光系統(tǒng)中，敷設(shè)的光纖不能用于多波長傳輸。另一方面，今天設(shè)計(jì)的光纖有寬的傳輸窗口，可以優(yōu)化用于大容量、多波長傳輸。 Specialized English on Communication Engineering The growing demand on optical network is a complex issue. O

26、n the one hand, the growth in capacity demand is extraordinary, and this in itself would be a big enough challenge to meet.extraordinary ：非凡的；顯著的對(duì)光網(wǎng)絡(luò)日益增長的需求是個(gè)復(fù)雜的問題。一方面，對(duì)容量需求的增長非常顯著，這本身就是一個(gè)需要面對(duì)的很大的挑戰(zhàn)。 Specialized English on Communication Engineering However, this is panied by an increasing variety of

27、 services and applications, as well as much more exacting requirements for quality differentiation. pany ：伴隨然而同時(shí)伴隨的是日益增長的各種業(yè)務(wù)和應(yīng)用，以及對(duì)不同業(yè)務(wù)的更加嚴(yán)格的需求。 Specialized English on Communication Engineering For example, there is quite a difference in the quality requirement for a signal being used to transmit a

28、n emergency telephone call or live video converge of a medical operation, as compared with an E-mail that is not urgent and can arrive after several hours.emergency ：緊急情況, 突然事件, 緊急事件urgent ：急迫的, 緊急的例如，用于傳輸緊急電話或者實(shí)況醫(yī)療手術(shù)轉(zhuǎn)播的信號(hào)，相比于不是很緊急的可以幾個(gè)小時(shí)后到達(dá)的電子郵件來說，信號(hào)質(zhì)量有很大的不同。Specialized English on Communication Eng

29、ineering However, the same optical infrastructure is expected to support this wide variety of services. Internet Protocol (IP) traffic, in particular, is growing exponentially. Internet Protocol (IP) traffic：IP業(yè)務(wù)IP：IP業(yè)務(wù)traffic：交通, 運(yùn)輸, 往來; 交通量; 運(yùn)輸量;交流; 傳達(dá), 傳輸信息;(電信)業(yè)務(wù), 通信量, 通話量然而，人們希望有光網(wǎng)絡(luò)結(jié)構(gòu)來支持這種廣泛的業(yè)務(wù)

30、。特別是IP業(yè)務(wù)，正在以指數(shù)形式增長。Specialized English on Communication Engineering In some parts of the world, it is expected that IP will constitute the majority of traffic in the near future. Therefore, existing networks will have to be progressively optimized to handle various types of traffic. progressively ：逐

31、步地optimize ：使最優(yōu)化在世界的一些地方，IP業(yè)務(wù)有可能在不久的將來構(gòu)成業(yè)務(wù)中的大部分。因此，現(xiàn)有的網(wǎng)絡(luò)必須逐步進(jìn)行優(yōu)化以處理各種類型的業(yè)務(wù)。Specialized English on Communication Engineering WDM has a major advantage in this regard, which is that the different types of traffic can be assigned to different wavelengths, as required. in this regard ：在這點(diǎn)上，在這方面WDM在這方面有很

32、大的優(yōu)勢(shì)，就是不同類型的業(yè)務(wù)按照需要可以分配不同的波長信號(hào)。Specialized English on Communication Engineering A further aspect to consider is access to the optical network. Most users would like to have direct access to the optical network and the enormous capacity it provides. This will take place in stages. access to the optica

33、l network ：接入（訪問）光網(wǎng)絡(luò)direct access ：直接接入（訪問）進(jìn)一步要考慮的是接入光網(wǎng)絡(luò)。多數(shù)用戶想直接接入到光網(wǎng)絡(luò)以利用其所提供的巨大信息的容量。著將會(huì)分成幾個(gè)階段來完成。Specialized English on Communication Engineering Multi-wave-length optical systems are rapidly spreading out from the core towards the end user. In regional and metropolitan areas, the requirements are

34、 somewhat different from the long-distance area. Multi-wave-length optical systems ：多波長光系統(tǒng)end user ：終端用戶多波長光系統(tǒng)正在快速地從核心網(wǎng)向終端用戶擴(kuò)展。在局部地區(qū)和城區(qū)的需求與長途通信有些不同。Specialized English on Communication Engineering The dream of Fiber To The Home (FTTH) or desktop is yet to materialize, mainly because of the cost-sens

35、itive nature of this part of the network.Fiber To The Home (FTTH) ：光纖到家（戶）materialize ：實(shí)現(xiàn)cost-sensitive ：費(fèi)用敏感性光纖到家（FTTH）或光纖到桌面的夢(mèng)想還需要經(jīng)努力去實(shí)現(xiàn)，主要是由于這部分網(wǎng)絡(luò)的費(fèi)用敏感性。Specialized English on Communication Engineering In the near future, residential access may remain copper-based, using technologies such as ADSL

36、 to boost the capacity of traditional copper lines. ADSL ：Asymmetrical Digital Subscriber Loop, 非對(duì)稱數(shù)字用戶環(huán)線copper-based ：基于銅線的在近來的一些日子里，住戶接入可能還是采用銅線，可以使用ADSL技術(shù)以增加傳統(tǒng)銅線的容量。Specialized English on Communication Engineering However, for business offices, optical technology will be used to bring bandwidth t

37、o the end-used. Currently, a lot of Fiber To The Building (FTTB) networks are being developed involving ATM and SDH access equipment at customer premises. Fiber To The Building (FTTB) ：光纖到建筑物ATM ：Asynchronous Transfer Mode 異步傳輸模式SDH ：Synchronous Digital Hierarchy 同步數(shù)字系列然而，對(duì)于商用辦公室，可采用光纖技術(shù)將帶寬送到終端用戶。目前

38、，很多光纖到建筑物網(wǎng)絡(luò)正在敷設(shè)中，這包括用戶房屋中的ATM和SDH接入設(shè)備。Specialized English on Communication Engineering The next step is to use WDM technology for these applications. WDM will first be used in industrial and campus Local Area Network (LAN) environments.Local Area Network (LAN) ：局域網(wǎng)下一步是在這些應(yīng)用中使用WDM技術(shù)。WDM將會(huì)首先用于工業(yè)和校園局域網(wǎng)

39、環(huán)境中。Specialized English on Communication Engineering We are at the beginning of a revolution in communications networks, where increasing capacity, variety of applications, and quality of service are placing enormous demands on the optical network. revolution ：革命我們正處于通信網(wǎng)絡(luò)革命的開始，越來越大的容量需求，各種各樣的應(yīng)用以及服務(wù)質(zhì)

40、量正在對(duì)光網(wǎng)絡(luò)提出巨大的需求。Specialized English on Communication Engineering The revolution of optical network is just beginning, and is advancing vary swiftly towards a future online world in which bandwidth is essentially unlimited, reliable and low-cost.online ：在線式unlimited ：無限的, 無約束的光網(wǎng)絡(luò)的革命剛剛開始，正在快速向未來的帶寬無限、可

41、靠和低費(fèi)用的在線世界發(fā)展。單信道全光中繼數(shù)字通信光-電-光中繼的數(shù)字通信典型通信鏈路方框圖Site ASite BPost OAPost OALine OAPre OAMUXDeMUX T1 T2 Tn-1 Tn R1 R2 Rn-1 Rn 波分復(fù)用器光發(fā)送器光接收器光 纜12n-1n 1, 2, nA 端B 端解復(fù)用器多路光波復(fù)用單纖傳輸復(fù) 習(xí)詞匯光纖通信 optical fiber communication光源 light source傳輸介質(zhì) transmission medium波長 wavelength激光器 laser色散 dispersion帶寬 bandwidth單模光纖 s

42、ingle-mode fiber復(fù) 習(xí)詞匯多模光纖 multi-mode fiber長途干線 long-haul trunk商用技術(shù) commercial technology寬帶用戶 wideband subscriber光檢測(cè)器 photodetector門限電流 threshold current纖維光網(wǎng)絡(luò) fiber-optic networks視頻帶寬 video bandwith復(fù) 習(xí)詞匯光纖通信系統(tǒng) fiber-optic communication system電磁波譜 electromagnetic spectrum電磁載波 electromagnetic carrier w

43、ave自由空間光通信 free-space optical communication寬帶綜合業(yè)務(wù)數(shù)字網(wǎng) broadband integrate-services digital network (BISDN)復(fù) 習(xí)詞匯repeater spacing 中繼距離commercial technology 商用技術(shù)optical fiber communication 光纖通信long-haul munication system 長途通信系統(tǒng)the low-loss silica fiber 低損耗石英光纖propagation mode 傳播模式refractive index profil

44、e 折射率分布圖optical receiver 光接收機(jī)dielectric 電介質(zhì)，絕緣材料復(fù) 習(xí)詞匯destructive interference 相消干擾（干涉）stepped-index fiber 階躍（折射率）光guided lightwave systems 引導(dǎo)型光波系統(tǒng)unguided optical systems 非引導(dǎo)型光波系統(tǒng)intersatellite communication 衛(wèi)星間通信long-haul munication 長途通信short-haul munications 短途通信central processing unit (CPU) 中央處理器

45、local area network (LAN) 局域網(wǎng)復(fù) 習(xí)詞匯wide area network (WAN) 廣域網(wǎng)network topology 網(wǎng)絡(luò)拓?fù)鋞oken ring network 令牌環(huán)網(wǎng)Wavelength Division Multiplexing (WDM) 波分復(fù)用Optical Amplifier (OA) 光放大器Fiber To The Home (FTTH) 光纖到戶Fiber To The Building (FTTB) 光纖到大樓小 結(jié)被動(dòng)語態(tài)及其譯法譯成漢語被動(dòng)句譯成漢語的主動(dòng)句譯成漢語的加強(qiáng)語句譯成漢語無主句WDM Specialized Engli

46、sh on Communication Engineering Fortunately, we will soon be in a position to route individual wavelengths flexibly through an optical network. Features such as add/drop and cross-connection in the optical domain are being made possible by advance in photonics. add/drop ：上下、分插cross-connection ：交叉連接photonics ：光子學(xué)幸運(yùn)的是，我們很快就可以通過光網(wǎng)絡(luò)靈活的傳送單個(gè)波長的信號(hào)。在光子學(xué)方面的發(fā)展使得在光域上具有信號(hào)上下和交叉連接的特性正在成為可能。Specialized English on Communication Engineering I would like to draw attention to a few recent advances in this area. Firstly, the so-called digital wrapper is in the process of being sta