光纤通信课程设计课件class1

1、Fiber Optic Network DesignX. Wu, M. J. Li, H. M. YanDept. of Opt. Engr., ZJU2011TypesHot SpotsFactorsLayoutNetworkHot SpotsTypesFactorsLayoutHot Spots in Design ConsiderationsMaximize the Profit (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）Optical

2、Cross-connectionElectronic Cross-connectionG.709GMPLSUltra long haul and super bandwidth10G, 25G, 40GTypesLayoutHot SpotsFactorsNetwork ClassificationClassified by Channel SpacingWide : WWDM Coarse: CWDM 20nmNarrow: NWDMDense: DWDM 100MHz, 0.2-1.2nmClassified by InterfacesOpenHalf-OpenIntegratedClas

3、sified by Channel NumbersChannel SpeedLayoutTypesHot SpotsFactorsA Typical WDM LayoutOSC/ESC: Optical/electrical Supervisory ChannelOTU: Optical Transport Unit (光转发单元)AttenuationAbsorption and ScatteringDispersionModalWaveguideMaterialPMDSignal-to-Noise ratioASE in EDFAAccumulated NoiseNonlinear Eff

4、ectsSPM, XPM, FWM, SBS,.FactorsLayoutHot SpotsTypesEffects on WDM by A number of FactorsLearning Network Design by Gaining a understanding of building blocksDesign idea- setup- performance testingRight tool for right job: OptisystemsPractice: In-class design 40%Homework 30%Final 30%WhatWhenHowGradeW

5、hat are we going to do in this courseCoverageSimpleAdd-onModifiedWhat are we going coverLinear DistortionAttenuation-BERDCFPMDWDM, DWDM, PONEDFA, RamanNonlinear DistortionFWM, SBSNetworkOCDMA, OFDM40G, 100G,CoverageSimpleAdd-onModifiedWhat for today? Basic P-to-PFamiliarity with OptisystemsParameter

6、 selectionHow to evaluate your resultBERSimplicityTotal cost: using BOMDesign processAnalyze your taskDefine your need: capacity, BER, cost,CoverageSimpleAdd-onModifiedA look at BER again Definition: The number of Bit errors that occur within the space of one second. Range: 10-9 to 10-12 The higher

7、the Data Transmission 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. CoverageSimpleAdd-onModifiedA look at BER again Test equipment: BERT BER tester two fundamental parts: signal

8、 pattern generator 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. BE

9、R = number of incorrectly received bits / total number of bits transmittedCoverageSimpleAdd-onModifiedQ factor and BER Why is BER difficult to simulate or calculate? For a given design BER estimate BER dynamically calculate Q from OSNR, ROP, eye-diagramCoverageSimpleAdd-onModifiedQ factor and BER Q

10、is a measure 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!CoverageSimpleAdd-onModifiedOSNR, Q factor and BER Optical signal to noise ratio (OSNR) Bit Error Rate The Eye diagram Q-factorCoverageSimpleAdd-onModifiedMo

11、re about OSNR 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-matte

12、r, 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 BERCoverageSimpleAdd-onModifiedCorrelation between OSNR and BER

13、Given 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 QdB=OSNR+10lo

14、g(BWo/Bwe), 1/OSNR=1/OSNR1+1/OSNR2+CoverageSimpleAdd-onModifiedEye DiagramIn transmission, a quick and qualitative measure of the quality and integrity of the electronic signal (since optical has been converted to electrical) is a superposition of bit periods on an oscilloscope. This superposition i

15、s known 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”CoverageSimpleAdd-onModifiedEye DiagramMinimum current threshold for

16、 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,maxCoverageSimpleAdd-onModifiedEye DiagramJitter: tEeye，EmaxCoverageSimpleAdd-onModifiedEye DiagramCoverageSimpleAdd-onModifiedEye Diagram and Q-factorCoverageSimpleAdd-onModifiedHomework: Power penalty Measure BER as a funct