课件光纤通信第一章

1、Fiber Optic Communications联系方式姓名： 钱胜Email： HYPERLINK mailto: Handset公地点：第一教研楼北楼428光纤通信网实验室2012年2月27日4时18分2Reference（）, JC Palais,电子工业出版社（教材）Fiber-Optic CommunicationsDjafar K. Mynbaev, Lowell L. Scheiner eds.,Pearson Education, Inc., 2001（教材）, DjafarK. , 徐功权等译, Gerd Keiser社2012年2月27日4时1

2、8分Chapter1ByQianSheng,HDUPage 3Introduction:Nature of lightTelecommunicationsA Fiber-Optic Communications System:The BasicBlocksA Look Back and a Glance AheadAdvantages of GlassFibersApplications of FiberSystemsSome numbers and units2012年2月27日4时18分Chapter1ByQianSheng,HDUPage 4Nature of LightSometime

3、s light behaves as a wave and sometimes light behaves as a particle. We will look at both behaviors.Nature of LightLight is an electromagnetic wave thatsatisfies MaxwellsEquations.The electromagnetic spectrum is a range frequencies classified intogroups.2012年2月27418分Chapter1ByQianSheng,HDUPage52012年

4、2月27418分Chapter1ByQianSheng,HDUPage6The spectrum of OFC10110210310410510610710810910101012101310141015ElectricphoneRadioAMFM无线电micro wave卫星/微波infra redVisible light光纤同轴电缆双铰线10710610510410310210110010-110-210-310-410-510-6Wave length（m）2012年2月27418分Chapter1ByQianSheng,HDUPage7Most of the frequencies

5、in fiber optic systems are In the Infrared.Wavelength and frequency are related by:vf(1.3)where v is the velocity of the wave in the medium.In free space,v = c = 3 x108 m/s2012年2月27418分Chapter1ByQianSheng,HDUPage8ffc3108m/s0.8510m3.5310Hz146T 1f13.5310140.281014sExample:If is 0.85 m, find theIn this

6、 example the medium is not specified, so let us assume that the medium isfreespace.The period of oscillation T is defined as the time it takes for the wave to complete one cycle. The period for the frequency in the preceding example is then2012年2月27418分Chapter1ByQianSheng,HDUPage9Fiber optic systems

7、 must havelowloss.glass low loss occurs at severalwavelengths.The major operation regions (windows) are:WavelengthWindow0.8-0.9FirstWindow1.300 Second Window1.550ThirdWindow1.600 FourthWindow2012年2月27418分Chapter1ByQianSheng,HDUPage102012年2月27418分Chapter1ByQianSheng,HDUPageParticle Nature of LightLig

8、ht is made up particles called photons. Each photon has energy:Wp h c(1.4)h = 6.626 x 10-34 J s (Plancksconstant)Shorter wavelength (higher frequency) waves have greater photon energy.2012年2月27418分Chapter1ByQianSheng,HDUPage12Example: How many photons are delivered each for a wave with average power

9、P=at wavelength = 0.8 m?AnswerW h 6.6261034 s3 108mspWp 2.481019Jphoton0.8106mW 1106JoulesW10612Wp2.481019 J photon4.03photons2012年2月27418分Chapter1ByQianSheng,HDUPage13The electron volt (eV) is another useful unit for analysis of fiberopticsystems.The electron volt is defined as the energy acquired

10、by an electron accelerated across a 1 voltpotentialdifference.conversion between electron volts and joulesis:1 eV = 1.6 x 10-19 JThe 0.8 photon has an energy (2.48/1.6)= 1.55eV2012年2月27418分Chapter1ByQianSheng,HDUPage14TelecommunicationsWhat It isTele-over a distance;communications- exchange of infor

11、mation;Telecommunications:exchangeof information over a distance using some type of equipmentInformation: voice, video data2012年2月27418分Chapter1ByQianSheng,HDUPage15A typical telephone system2012年2月27418分Chapter1ByQianSheng,HDUPage16Message iginElectric DomainDestinatio ProcessorMessage iginElectric

12、 DomainDestinatio ProcessorDetectorCouplerOrModulatorCarrierOpticDomainChannelSourceCouplern2012年2月27418分Chapter1ByQianSheng,HDUPage17Telecommunications: point to point systems networksnetworksPoint to point systemNodesTransmitterReceiver23InformationInformation ChannelInformation1N5Station4Link2012

13、年2月27418分Chapter1ByQianSheng,HDUPage18Information- carrying capacity1 Why produce more information? InformationEra:need information2012年2月27418分Chapter1ByQianSheng,HDUPage19MbpsMbps2012年2月27418分Chapter1ByQianSheng,HDUPage20From 29thICCNC2012年2月27日4时18分21From 29thICCNC1987年9月20日,在德国卡尔斯鲁厄大学教授维纳措恩的帮助下,

14、中国首次接入国际互联网.当天,维纳措恩教授和中国互联网先驱王运丰教授联手起草了中国第一封跨国电子邮件,从北京成功发往德国的卡尔斯鲁厄.这标志着中国跨出了走向互联网时代的第一步.2012年2月27日4时18分222 Why go digital?Analog (continuous)TimeDigital (discrete)10101012012年2月27418分Chapter1ByQianSheng,HDUPage23CauseEffectLossAttenuation GainAmplification & NoiseDistortion2012年2月27418分Chapter1ByQia

15、nSheng,HDUPage24Pulse-code modulation(PCM) technique2012年2月27418分Chapter1ByQianSheng,HDUPage25Digitizing StepsDigitizing StepsPick the highest fu = 4 kHz forvoiceSample at twice the highestfrequencyyielding: :Sampling Rate = 2fu = 8000 samples/secondUse an 8-bit code for each sample. That is, aseque

16、nceof 8 bits.One 8-bit number consists of 8 time slots, each containing a binary 0 or 1. There are 256 possible combinations, since 28 = 256. Thus, a sequence of 8 bits (combinations of zeroes and ones) will represent the amplitude of each sample.2012年2月27418分Chapter1ByQianSheng,HDUPage26Calculate t

17、he data rate:8000(samples/s) x 8 (bits/sample) = 64,000 b/s Therefore, there are 64,000 b/s transmitted for a digitized voice message.2012年2月27418分Chapter1ByQianSheng,HDUPage27The need for fiber-optic communications systemShannon-Hartley Theorem: C=BWlog2(1+SNR)Communication modeCapacity/channelRela

18、y distance/kmThe number of repeaters in1000 kmMicrowave20 0005020Coaxial cable13 0004250Satellite100 000Optical fiber3 000 000 000100km10The information-carrying capacity of a telecommunications system is proportional to its bandwidth, which in turn is proportional to the frequency of the carrier.20

19、12年2月27418分Chapter1ByQianSheng,HDUPage28A fiber-optic communications system: the basic blocks2012年2月27418分Chapter1ByQianSheng,HDUPage292012年2月27418分Chapter1ByQianSheng,HDUPage30Basic block diagram2012年2月27418分Chapter1ByQianSheng,HDUPage31Transmitter2012年2月27418分Chapter1ByQianSheng,HDUPage32Optical F

20、iber2012年2月27418分Chapter1ByQianSheng,HDUPage33Receiver2012年2月27418分Chapter1ByQianSheng,HDUPage34The role of fiber- optic communications technologyNot only changed landscape of telecommunications, butalsochanged peopleslivesWDMErFA100012012年2月27418分Chapter1ByQianSheng,HDUPage35A look back and a glanc

21、e aheadLight as the great communicatorOptical communication systems notnewGreek chains with relay stationsexisted 1000yearsBCMissing for a long time was the perfect matchofbandwidth, distance and reliability2012年2月27418分Chapter1ByQianSheng,HDUPage36Early communications used lightsignals.Hand signals

22、 used light as an informationThe modulator was the hand of theThe detector was the eye of theThe processor was the brain of the2012年2月27418分Chapter1ByQianSheng,HDUPage37Early Optical CommunicationsSmokesignalsBlinkerlightsPhotophone: invented by Alexander GrahamBellProperties of early optical commun

23、ications systems:slow data ratepoor high errorrate2012年2月27418分Chapter1ByQianSheng,HDUPage38New attempts1960: LaserinventedMaiman1960-1970 Time Period:Many laser applications were proposed.Oneproposalwasfor anopticalcommunications link operated line-of-sight though theatmosphere.2012年2月27418分Chapter

24、1ByQianSheng,HDUPage39ProblemsA clear atmosphere was required for efficient transmission.The unguided atmospheric system needed an unobstructed line-of-site.Once this decision was reached, the problem of how toguide the light arose.2012年2月27418分Chapter1ByQianSheng,HDUPage40The guided light1870-Tynda

25、ll （optical societyofAmerica2012年2月27418分Chapter1ByQianSheng,HDUPage411951： Heel和BrianOBrien（cladding）2012年2月27418分Chapter1ByQianSheng,HDUPage421966,Charles K. 2012年2月27418分Chapter1ByQianSheng,HDUPage43SolutionIn 1970, a low-loss, glass fiber waveguide was developed at Corning.2012年2月27418分Chapter1B

26、yQianSheng,HDUPage441970, BellGaAlAsLD100,000 hours (about 11.4years)；The first-GTE Long Beach6 Mb/s1989-Erbium doped fiber amplifier2012年2月27418分Chapter1ByQianSheng,HDUPage45the industry today and future trends2012年2月27418分Chapter1ByQianSheng,HDUPage46FiberOpticsof 21STVery important for modern dat

27、a transfer and communication systems phones!2012年2月27418分Chapter1ByQianSheng,HDUPage47Modern OpticalCommunications2012年2月27418分Chapter1ByQianSheng,HDUPage48First Generation, 1975, 0.8 m MM-fiber, GaAs-laser or LEDSecond Generation, 1980, 1.3 m, MM & SM-fiberInGaAsP FP-laser or LEDThird Generation, 1

28、985, 1.55 m, SM-fiberInGaAsP DFB-laser, 1990 Optical amplifiersFourth Generation, 1996, 1.55 mWDM-systems2dB/cm1977年美国率先在芝加哥相距7km的两个电信局间进行传送44.736Mbit/s的商用光纤数dB/km，光源使用铝镓砷半导体激1.1 1.21.3 1.4 Wavelength (m)光器，光电探测器采用硅材料制作。这次试验标志着第一代光纤通信系统进入实用化阶段，从此拉开了光纤通信实用化的序幕2012年2月27418分Chapter1By

29、QianSheng,HDUPage49NOWCanada LMGR 65536waves World Record （Japan，5,18,2004）about10Tb/s/fiber（2001）China:OptiXBWS1600G,46 00km, 4010G 日经产业新闻2004年5月18传4部两小时长的电影。 16倍，已经在距离为80公里的传2004年世界科技十大进展（中科院）2012年2月27418分Chapter1ByQianSheng,HDUPage50Worldwide submarine networks cables:In1989transatlantic cables w

30、here introduced that could handle 40,000 voicecalls. Now all the major oceans and seas have fiber cables lying beneath them.2012年2月27418分Chapter1ByQianSheng,HDUPage512012年2月27418分Chapter1ByQianSheng,HDUPage52Fiber-to-the-home and fiber-to-the-deskWhat is FTTH?Copper/FiberCO/HECO/HE/Old networks, opt

31、imized forvoice24 kbps - 1.5MbpsCO/HE/Optical networks, optimized forvoice,video19 Mbps - 1 Gbps+and dataNote: network may be aerial or underground2012年2月27418分Chapter1ByQianSheng,HDUPage532002 FTTH networks350,000300,000315,000Greenfield 29%Overbuild 71%250,000200,000150,000100,00050,000019,40072,1

32、00110,000 as of March, 2003FTTH homes passed in US and Canada2012年2月27418分Chapter1ByQianSheng,HDUPage54 Fiber optics in LANs and beyond Communications along highvoltagelines:are not affected by interference from these lines.OPGWWRAP AROUNDADSS2012年2月27418分Chapter1ByQianSheng,HDUPage55Developments to

33、 watch2008年3月通过架设在两栋相距210米远楼顶的无线天线，意大利和日本科学家通过一套基于激光的无线传输系统成功实现了1.28Tb/s的传输速度。1.28Tb/s数据流由实验室的一楼通过光纤抵达位于楼顶的第1 个自由空间光系统天线，然后信号被发送到空气中，在另外一栋楼楼顶的第2个天线收集到了这些信号，然后通过同样的设备转换为数据再通过光纤传回了实验室。最终的实验结果达到了1.2Tb/s(32个通道每个通道 40Gbit/s)，这一数据超过了之前在韩国创造的160Gb/s (16个通道每个通道10Gbit/s)的记录。日经产业新闻2008年3月19日报道说，日本电气公司和东京工业大学联

34、合试制出一种采用光传输技术的装置，由半导体激光器和数千根光回路组成。其中的半导体激光器能将电信号转换成光信号，光回路则可以在大规模集成电路之间传输光信号。它以每秒250亿比特的速率，创下迄今大规模集成电路间数据传输的世界最高速纪录。研发的这种装置，超级计算机要实现超高速运算，其内部多个大规模集成电路需要彼此连接。现有多数超级计算机采用电子线路连接大规模集成电路，要实现每秒100亿比特以上的高速数据传输非常困难，但光传输技术可以突破这个极限。2012年2月27418分Chapter1ByQianSheng,HDUPage57High high SpeedLong lengthOpticalnet

35、workintegrateddeviceFifth Generation-Solitoncommunication2012年2月27418分Chapter1ByQianSheng,HDUPage58Advantages of Glass FibersCost: The cost of fiber is very low, because glass is plentiful and cheap. Silica fibers have abundant raw material .Weight:Fiber cables are smaller than cables and weigh much

36、less.Strength:Fibers are strong and flexible, enabling them to goaroundcorners.Glass fibers have a high tensilestrength.2012年2月27418分Chapter1ByQianSheng,HDUPage59Highinformationcapacity:Glass fiber can carry signals then a conducting cable. 1.3 mm . 1.55 mm allocates bandwidth of 37THz!Shannon:C=BWl

37、og2(1+SNR）LowLoss:As the modulation frequency increases, coaxial cable losses increase at a faster rate thanfiber losses.Optical fiber loss can be as low as 0.2 dB/km. Compare to loss ofcoaxial cables: 10 300 dB/km !2012年2月27418分Chapter1ByQianSheng,HDUPage60Applications of Fiber SystemsCableFrequenc

38、y-division-multiplexing (FDM) is used to transmit television signalsover fiber systems. Each television channel has a bandwidth of 6MHz.PowerTV Baseband SignalPower06MHzf (Hz)2012年2月27418分Chapter1ByQianSheng,HDUPage61The television signal can be modulated onto a sub- carrier frequency fo. The baseba

39、nd signal has been shifted upwards in frequency.6 MHzPowerTV Channel6 MHzPower0fosub-carrierf (Hz)2012年2月27418分Chapter1ByQianSheng,HDUPage62Several television channels can be multiplexed onto different sub-carrier frequencies and the result used to modulate a light source.Electrical1Electrical6 MHzC

40、hannels2346 MHz6 MHz6 MHz0f1f3f (Hz)Sub-Carrier Frequencies2012年2月27418分Chapter1ByQianSheng,HDUPage63At the receiver the television signals are demultiplexedby filters.Several tens of television channels can be transmitted by division-multiplexing (FDM) on a single2012年2月27418分Chapter1ByQianSheng,HD

41、UPage64trunk lines :In1976-77large-scale fiber lines were first deployed to connecttelephone exchanges at45Mb/s.Fiber data rates are now beyond 10 Gb/s. cables:In1989transatlantic cableswhere introduced that could handle 40,000 voice calls. Now all the major oceans and seas have fiber cables lying b

42、eneath them.2012年2月27418分Chapter1ByQianSheng,HDUPage652012年2月27418分Chapter1ByQianSheng,HDUPage662012年2月27418分Chapter1ByQianSheng,HDUPage672012年2月27418分Chapter1ByQianSheng,HDUPage68Wiredcity（有线化城市）:Due to increased demand, fiber-to-the-home and fiber-to-the-curb systems are available to bring higher

43、data rates for video and internet applications to and to thehome.Communications along electric railways: are not affected by electrical interference from the railways.2012年2月27418分Chapter1ByQianSheng,HDUPage6940,00035,00030,00025,00020,00015,00010,0005,0000Homes (United States and Canada)22,50010,35

44、05,50038,000Sep 01Mar02Sep Mar Source: Render, Vanderslice & Associates2012年2月27418分Chapter1ByQianSheng,HDUPage70OPGWOPGWADSSWRAPAROUNDCommunications along highvoltagelines:are not affected by interference from theselines.2012年2月27418分Chapter1ByQianSheng,HDUPage712012年2月27418分Chapter1ByQianSheng,HDU

45、Page722012年2月27418分Chapter1ByQianSheng,HDUPage73Other video applications such as remotemonitoring andsurveillance.Local area networks (LANs), computers, file e.g.,Ethernet.Military applications such as tactical command telecommunications and fiber-guidedmissiles.2012年2月27418分Chapter1ByQianSheng,HDUP

46、age74Sensors:Measurements of temperature, pressure,motion and more.The following is an example for a hydrophone sound sensor.Free FiberFixed MonitorLight SourceFluidDetectorsound waveThe hydrophone works on the principle of externalmodulation.The light is modulated by motion of the fibers, causingmi

47、salignments in the transmission system, resulting in a change in powerreceived.2012年2月27418分Chapter1ByQianSheng,HDUPage75FiberOpticGyro(cont.)The fiber coils may comprise several hundred turns and have a diameter of 0.1-0.2 me.g. 200 turns, 0.1m:=corresponds to738800deg/hrNorthrop Grumman IMU 600 Pa

48、rticularly well suited for tactical missile and torpedo guidance/navigationThe IMU 200incorporates three FOG 200s and three accelerometers for highly accurate inertial sensing, achieving 0.1 deg/hr in-run drift stability. A version of this IMU is used as part of the National Missile Defense System.2

49、012年2月27Northrop Grumman IMU 600 Particularly well suited for tactical missile and torpedo guidance/navigationThe IMU 200incorporates three FOG 200s and three accelerometers for highly accurate inertial sensing, achieving 0.1 deg/hr in-run drift stability. A version of this IMU is used as part of th

50、e National Missile Defense System.Whats inside?2012年2月27日4时18分77Fiberopticchemicalsensors (FOCS)Many of commercial FOCS arecoating-based sensors.A portion of the cladding isreplaced by a proprietary coating, which selectively and reversibly adsorbs the organic target analytes.The coating adsorbs org

51、anics while repelling water.the coating.hydrophobic/organophilicThe interaction between the organic target analytes and the coating the coating.hydrophobic/organophilicchemical coating.The change in the index decreases the amount of light generated by an LED transmitting to the detector. The resulta

52、nt loss of light is measured in proportion to the concentration of organics2012年2月7r1entinthesampe. 78Chemresistor(cont.)2012年2月27日4时18分79Photosensor for NightvisionInSb does not offer sensitivity in the 10-20 um region, but is more easily made,electronics compatible, can be operated near Research to extend the operation to higher temperatures is underway throughout academia and industry2012年2月27日4时18分80Sample Images2012年2月27日4时18分81Some numbers and unitsPREFIXESPrefixSymbolMultiplication teraT1012gigaG109m