中英對照：光纖通信(文件)
【正文】 來。他利用電端機(jī)輸送載有信息的電信號通過光調(diào)制器對光源發(fā)出的連續(xù)廣播的振幅、相位或頻率進(jìn)行調(diào)制，從而輸出載有有用信息的光信號，再將該光信號耦合進(jìn)光纖傳輸線路。它非常適合于長距離單信道光纖通信系統(tǒng)第三篇：光纖通信光纖通信系統(tǒng)包括實(shí)現(xiàn)點(diǎn)對點(diǎn)通信的全部設(shè)施，主要偶傳輸系統(tǒng)，用戶終端，接入設(shè)備和交換設(shè)備四個部分組成。(3)這種光纖工作波長即可選在1310nm波長區(qū)域，又可選在1550nm波長區(qū)域，它的最佳工作波長在1310nm區(qū)域。前兩種色散由于信號不是單一頻率所引起，后一種色散由于信號不是單一模式所引起。m, and the new dry fiber has a lowloss window promising an extension of that range to developments include the concept of “optical solitons, “ pulses that preserve their shape by counteracting the effects of dispersion with the nonlinear effectsof the fiber by using pulses of a specific the late 1990s through 2000, industry promoters, and research panies such as KMI and RHK predicted vast increases in demand for munications bandwidth due to increased use of the Internet, and mercialization of various bandwidthintensive consumer services, such as video on protocoldata traffic was increasing exponentially, at a faster rate than integrated circuit plexity had increased under Moore’s the bust of the dot bubble through 2006, however, the main trend in the industry has been consolidation of firms and offshoring of manufacturing to reduce , panies such as Verizon and ATamp。m and used GaAs semiconductor firstgeneration system operated at a bit rate of 45 Mbps with repeater spacing of up to 10 on 22 April, 1977, General Telephone and Electronics sent the first live telephone traffic through fiber optics at a 6 Mbit/s throughput in Long Beach, second generation of fiberoptic munication was developed for mercial use in the early 1980s, operated at 181。此外一些新興的網(wǎng)絡(luò)應(yīng)用，如隨選視頻（video on demand）使得互聯(lián)網(wǎng)帶寬的成長甚至超過摩爾定律（Moore’s Law）所預(yù)期集成電路芯片中晶體管增加的速率。第五代光纖通信系統(tǒng)發(fā)展的重心在于擴(kuò)展波分復(fù)用器的波長操作范圍。第四代光纖通信系統(tǒng)引進(jìn)了光放大器（optical amplifier），進(jìn)一步減少中繼器的需求。1980年代末，EDFA的誕生，堪稱光通信歷史上的一個里程碑似的事件，它使光纖通信可直接進(jìn)行光中繼，使長距離高速傳輸成為可能，并促使了DWDM的誕生。第二代的商用光纖通信系統(tǒng)也在1980年代初期就發(fā)展出來，使用波長1300納米的磷砷化鎵銦（InGaAsp）激光。與此同時使用砷化鎵（GaAs）作為材料的半導(dǎo)體激光（semiconductor laser）也被發(fā)明出來，并且憑借著體積小的優(yōu)勢而大量運(yùn)用于光纖通信系統(tǒng)中。到了二十世紀(jì)中葉，人們才了解使用光來傳遞信息，能帶來很多過去所沒有的顯著好處。到了2002年時，越洋海底電纜的總長已經(jīng)超過25萬公里，而且根據(jù)電信業(yè)者的統(tǒng)計(jì)，這些數(shù)據(jù)從2002年后仍然不斷的大幅成長中。然而，在城市之間利用光纖的通信基礎(chǔ)建設(shè)（infrastructure）通常施工難度以及材料成本難以控制，完工后的系統(tǒng)維運(yùn)復(fù)雜度與成本也居高不下。與傳統(tǒng)的銅線相比，光纖的信號衰減（atte
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