简介:TheanalysisofcelllossratesinanATMMuxwithlossprioritiesisanimportantprobleminthe-studyoftrafficcontrolinATMnetworks.Inthispaper,thelossratesofthecellswithdifferentprioritiesinanATMMuxareanalyzedbyapproximatingtheactualinputprocesswithtwo-stateMMDPandfluidflowtechnique,andtheanalyticalexpressionsoftherelationbetweenthelossratesandthebuffersizeareobtained.Simulationshowsthattheapproachissullicientlyaccurateforapplications.
简介:Themechanismofγ-rayradiationinducedabsorptionlossoftheopticalfiberinvisiblerangeisanalyzed.Accordingtothemechanism,thequantitativerelationbetweenlossinopticalfiberandγ-raycumulationdoseisfoundbyuseofmethodsofsolidphysicsandstatisticphysics.Thisquantitatierelationiscertifiedintermsoftheresultsofradiationexperiment.
简介:Weproposeafullydistributedfusionsystemcombiningphase-sensitiveopticaltime-domainreflectometry(Φ-OTDR)andOTDRforsynchronousvibrationandlossmeasurementbysettinganingeniousfrequencysweeprate(FSR)oftheopticalsource.TherelationshipsbetweenFSR,probepulsewidthandrepeatperiodaregiventobalancetheamplitudefluctuationofOTDRtraces,thedeadzoneprobabilityandthemeasurablefrequencyrangeofvibrationevents.Intheexperiment,weachievesynchronousvibrationandlossmeasurementwithFSRof40MHz/s,theproblepulsewidthof100nsandrepeatrateof0.4ms.ThefluctuationofOTDRtraceislessthan0.45dBwhenthesignalto-noiseratio(SNR)isover12dBforacapturedvibrationeventlocatedat9.1km.Theproposedmethodcanbeusedfornotonlydetectionbutalsoearlywarningofdamageeventsinopticalcommunicationnetworks.
简介:Toreducethecomputationburdenofalarge-aperturemultiple-inputmultiple-output(MIMO)sonarimagingsystem,thephase-shiftbeamformer(PSBF)isusedatthecostofbringingtheintensityloss(IL).ThecauseoftheILisanalyzedindetailandavariabletermedasILfactorisdefinedtoquantifythelossamount.TocompensatefortheIL,twomethodstermedasintensitycompensationforthePSBF(IC-PSBF)andthehybridbeamforming(HBF),respectively,areproposed.TheIC-PSBFusespreviouslyestimatedILfactorstocompensateforoutputintensitiesofallPSBFs;andtheHBFappliestheIC-PSBFtothecenterbeamregionandtheshifted-sidebandbeamformer(SSBF)tothesidebeamregion,respectively.Numericalsimulationsdemonstratetheeffectivenessofthetwoproposedmethods.
简介:TheISMbandat2.4GHzhasmostlybeenusedorplannedforindoorsystems.Thisbandisalsoattractiveforoutdoorsystemsowingtotheeaseofthesystemdeployment,asnofrequencylicensesarerequired.Inthispaper,amultiplesuccessiveinternalmultireflectionmodelisusedtoestimatethecomplexelectricpermittivityat2.4GHzband.Toobtainthedata,measurementsareperformedat160MHzbandwidthcenteredabout2.4GHzusingavectornetworkanalyzer,whichprovidesinformationabouttheamplitudeandphaseoftransmissioncoefficient.Severalsamplesofeachmaterialaremeasuredandtheresultsvaryfromsampletosample.Ithasalsobeenfoundthatsomeobstacleshavepolarizationbehaviour.
简介:ExistingEthernetPassiveOpticalNetwork(EPON)DynamicBandwidthAllocation(DBA)algorithmssufferfromthedisadvantageofidletimeloss,whichlowertheupstreambandwidthutili-zation.Thisletterproposesanimprovedupstreamtransmissionschemewithidle-timeeliminatingmechanism.Theoreticalanalysisandnumericalcalculationprovethattheimprovedschemecanef-fectivelyeliminatetheidletimeandenhancetheefficiencyofupstreamlinkutilization.Simulationresultshaveshownthatthebandwidthutilizationcanberaisedupto15%inheavy-loadscenarioswhilethetimedelayperformanceofAssuredForwarding(AF)andBestEffort(BE)servicesareimprovedsimultaneously.
简介:Theconfinementlossandbendlosspropertiesofall-solidphotonicbandgapfiberswithanarrayofringsdopedwithhighindexmaterialareinvestigated.Thecalculatedresultsshowthatforaspecificstructure,theconfinementlossandthecriticalbendradiusarereducedsimultaneouslyinsomebandgapsbyincreasingtheinnerdiameterofring,whichprovidesausefulguideandatheoreticalbasisfordesigninglargemodeareafiberswithlowloss.
简介:Thehighpowerholeyfiberisanefficientsupercontinuumlightsourcebyusingpicosecondpulse,whichisalessexpensivelasersourcecomparedwithlowpowerandexpensivefemtosecondlasersources.Inthispaper,ahighpowerhighlynonlinearholeyfiber(HN-HF)withalowconfinementlossisproposedforsupercontinuumlightsources.ThefinitedifferencemethodisusedtocalculatethedifferentpropertiesoftheproposedHN-HF.Highnonlinearcoefficientsareobtainedat1.06μm,1.31μm,and1.55μmwavelengthswithflattenedchromaticdispersionandlowconfinementlossessimultaneously.Moreover,numericalsimulationresultsshowthathighpowerbroadsupercontinuumspectrawithveryshortlengthoftheproposedphotoniccrystalfiberareachieved.
简介:Alow-lossfiberopticrotaryjoint(FORJ)hasbeendesignedbyusingtwokindsofC-lenscollimators.Itsinsertionlossandinsertionlossvariationduetorotationwithsingle-modefibercollimatorislessthan1.76dBand0.43dBrespectively.Themaximuminsertionlossandcouplingvariationduetorotationwithmulti-modefibercollimatoris1.71dBand0.29dB,respectively.ThiskindofFORJfeatureslowinsertionloss,smallcouplingvariationduetorotationandlowcost.
简介:WereportthedepositionofNb2O5filmsonunheatedBK-7glasssubstratesusingremoteplasmasputteringsystem.Theremoteplasmageometryallowspseudoseparationofplasmaandtargetbiasparameters,whichofferscompletedepositionratecontrol.Usingappropriateoxygenflowrates,high-densityandlow-lossNb2O5filmsaredepositedwithratesupto0.49nm/s.Lowerdepositionrates(~0.026nm/s)canalsobeobtainedbyworkingatlowtargetcurrentandvoltageandatlowpressure.Nb2O5filmsdepositedatdifferentrateshavetherefractiveindexofabout2.3andtheextinctioncoefficientaslowas6.9×10-5.
简介:Thestructureoftheopticalwaveguideof2-bitelectroopticA/Dconverterwithproton-exchangemicroprismsisoptimizedbythefinite-differencebeampropagationmethod(FD-BPM).Theelectrodeparametersoftheconverterareoptimizedbyconformalmapping.Theoptimalparametersareahalf-wavevoltageofVπ=4.5VandabandwidthofΔf=1.4GHz.Anormalizedtransmittedpowerof69.75%isobtainedbyFD-BMPandtheoutputwaveguidegapis300μm.
简介:Gradient-indexrodlens(GRIN-lens)whosepitchisordinaryvaluewithbevelferrulecouplingsystemisanalyzed,anequivalentmethodwhichcanbeusedtoanalyzethissystemisputforward,andageneralformulafordeterminingthecouplinglosswithaxesmismatch,radialmismatch,andangularmismatchisderivedbyuseoftheGaussianfieldapproximationandmode-fieldcouplingtheory.Theexperimentalresultsareingoodagreementwiththetheoryprediction.Itindicatesthattheseformulasaresuitabletoanalyzethegradient-indexrodlenscouplingsystemwithpigtailfiber.
简介:新奇biopolymer,脱氧核糖核酸acid-hexadecyltrimethylammonium氯化物(DNA-HCTAC),当在光波导的核心层材料,和cleanroom技术成功地被使用与低繁殖损失制作单个模式的隧道波导,被使用。准备DNA-HCTAC材料在光电信波长显示出高光的质量,例如高透明性,相对高的折射索引和低birefringence。在制造途径,polymethylmethacrylate(PMMA)被用作障碍层保护DNA-HCTAC材料免受光致抗蚀剂开发者的腐蚀剂的伤害,并且蚀刻的条件被优化形成光滑的墙和波导的锋利的剖面图。最后,DNA-HCTAC隧道波导的光特征被测量。结果证明DNA-HCTAC波导与单个模式的繁殖操作并且有低光损失。