光纤通信课程设计课件Class1-03.pptx

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1、TypesTypesHot Hot SpotsSpotsFactorsFactorsLayoutLayoutHot Hot SpotsSpotsTypesTypesFactorsFactorsLayoutLayoutMaximize the Profit(利益最大化）利益最大化）IP over WDMInstead of using IP over SDH over WDM,direct IP over WDM is employedOTN(光传送网）光传送网）Optical Cross-connectionElectronic Cross-connectionG.709GMPLSUltra

2、long haul and super bandwidth10G,25G,40GTypesTypesLayoutLayoutHot Hot SpotsSpotsFactorsFactorsClassified by Channel SpacingWide:WWDM Coarse:CWDM 20nmNarrow:NWDMDense:DWDM 100MHz,0.2-1.2nmClassified by InterfacesOpenHalf-OpenIntegratedClassified by Channel NumbersChannel SpeedLayoutLayoutTypesTypesHo

3、t Hot SpotsSpotsFactorsFactorsOSC/ESC:Optical/electrical Supervisory ChannelOTU:Optical Transport Unit(光转发单元光转发单元)AttenuationAttenuation Absorption and ScatteringAbsorption and Scattering DispersionDispersion ModalModal WaveguideWaveguide MaterialMaterial PMDPMD Signal-to-Noise ratioSignal-to-Noise

4、ratio ASE in EDFAASE in EDFA Accumulated NoiseAccumulated Noise Nonlinear EffectsNonlinear Effects SPM,XPM,FWM,SBS,.SPM,XPM,FWM,SBS,.FactorsFactorsLayoutLayoutHot Hot SpotsSpotsTypesTypesLearning Network Design by Learning Network Design by Gaining a understanding of building blocksGaining a underst

5、anding of building blocksDesign idea-setup-performance testingDesign idea-setup-performance testingRight tool for right job:OptisystemsRight tool for right job:OptisystemsPractice:Practice:In-class design 40%In-class design 40%Homework 30%Homework 30%Final 30%Final 30%WhatWhatWhenWhenHowHowGradeGrad

6、eCoverageCoverageSimpleSimpleAdd-onAdd-onModifiedModifiedLinear DistortionAttenuation-BERDCFPMDWDM,DWDM,PONEDFA,RamanNonlinear DistortionFWM,SBSNetworkOCDMA,OFDM40G,100G,CoverageCoverageSimpleSimpleAdd-onAdd-onModifiedModified Basic P-to-PFamiliarity with OptisystemsParameter selectionHow to evaluat

7、e your resultBERSimplicityTotal cost:using BOMDesign processAnalyze your taskDefine your need:capacity,BER,cost,CoverageCoverageSimpleSimpleAdd-onAdd-onModifiedModified Definition:The number of Bit errors that occur within the space of one second.Range:10-9 to 10-12 The higher the Data Transmission

8、rate the greater the standard.DS-1(1.544 Mbit/s)signal is considered acceptable with a BER of 10-6,OC-3(155.52 Mbit/s)signal requires a BER of no more than 10-12.CoverageCoverageSimpleSimpleAdd-onAdd-onModifiedModified Test equipment:BERT BER tester two fundamental parts:1.signal pattern generator 2

9、.error detector Signal pattern generator Producing a known data sequence,intentionally stress some aspect,like difficult for the clock recovery system to synchronize.Most common pattern:pseudo-random binary sequence(PRBS)Error detectorcompared bit by bit between two signals.BER=number of incorrectly

10、 received bits/total number of bits transmittedCoverageCoverageSimpleSimpleAdd-onAdd-onModifiedModified Why is BER difficult to simulate or calculate?For a given design BER estimate BER dynamically calculate Q from OSNR,ROP,eye-diagramCoverageCoverageSimpleSimpleAdd-onAdd-onModifiedModified Q is a m

11、easure of the quality of any signal If the noise is known to be Gaussian,Q fully determines BER In many cases,Q(10)Q6:A rule of thumb!CoverageCoverageSimpleSimpleAdd-onAdd-onModifiedModified Optical signal to noise ratio(OSNR)Bit Error Rate The Eye diagram Q-factorCoverageCoverageSimpleSimpleAdd-onA

12、dd-onModifiedModified OSNR is important because it suggests a degree of impairment when the optical signal is carried by an optical transmission system that includes optical amplifiers.Optical signal suffers more than only attenuation.In amplitude,spectrally,temporally signal interaction with light-

13、matter,light-light,light-matter-light Leading to Signal disturbances such as:Power reductionDispersionPolarizationUnbalanced amplificationThus leading to random noise,which causes misalignments,jitter and other disturbances resulting in BERCoverageCoverageSimpleSimpleAdd-onAdd-onModifiedModifiedGive

14、n the OSNR,the empirical formula to calculate BER for single fiber is Log10(BER)=10.7-1.45(OSNR)Example:Assume that OSNR=14.5 dB Then Log10(BER)=10.7-1.45(14.5)=-10.30 Therefore BER=10-10.30 BER is approx 10-10More complicated calculations may refer to CISCO webpage http:/ QdB=OSNR+10log(BWo/Bwe),1/

15、OSNR=1/OSNR1+1/OSNR2+CoverageCoverageSimpleSimpleAdd-onAdd-onModifiedModifiedIn transmission,a quick and qualitative measure of the quality and integrity of the electronic signal(since optical has been converted to electrical)is a superpositionofbitperiodsonanoscilloscope.This superposition is known

16、 as the“eye diagram”If the signal has little noise and the amplitude is sufficient to be clearly recognized as“one”(marks)or“zero”(spaces)the superposition provides an“open eye”,otherwise eye is corrupted and“fuzzy”CoverageCoverageSimpleSimpleAdd-onAdd-onModifiedModifiedMinimum current threshold for

17、 logic 1 is set to I 1,min Maximum current threshold for logic 0 is set to I0,maxOpening of the Eye,E Eye=I 1,min-I 0,maxCoverageCoverageSimpleSimpleAdd-onAdd-onModifiedModifiedJitter:tEeye，EmaxCoverageCoverageSimpleSimpleAdd-onAdd-onModifiedModifiedCoverageCoverageSimpleSimpleAdd-onAdd-onModifiedMo

18、difiedCoverageCoverageSimpleSimpleAdd-onAdd-onModifiedModified Measure BER as a function of mean receivedopticalpower(ROP)for each ROP,decision threshold is optimized,and the BER measured Receiver sensitivity is the ROP required to achieve a specific BER(10-9,10-12)Find power penalty for with and without“optically amplified link”