简介:AslowlightstructureMach-Zehnderfiberinterferometeristheoreticallydemonstrated.Thesensitivityoftheinterferometerissignificantlyenhancedbythedispersionoftheslowlightstructure.Thenumericalresultsshowthatthesensitivityenhancementfactorvarieswiththecouplingcoefficientandreachesitsmaximumundercriticalcouplingconditions.
简介:ThisworkpresentsanopticalmethodusingtheMach–Zehnderinterferometer.Weespeciallydiagnoseapurenitrogengassubjectedtoapointtoplanecoronadischarge,andvisualizethedensityspatialmap.Theinterelectrodedistanceequals6mmandthevariationoftheopticalpathhasbeenmeasuredatdifferentpressures:220Torr,400Torr,and760Torr.TheinterferogramsarerecordedwithaCCDcamera,andthenumericalanalysisoftheseinterferogramsisassuredbytheinverseAbeltransformation.ThenitrogendensityisextractedthroughtheGladstone–Dalerelation.Theobtainedresultsareincloseagreementwithvaluesavailableintheliterature.
简介:聚合Mach-Zehnder肋骨波导的系统的分析基于计算和优化被介绍。模拟与有效索引方法(EIM)被执行并且二维(2-D)有限差别横梁繁殖方法(FD-BPM)。在连续聚合物层之间的大折射索引步被使用EIM减少,因此,计算的精确被保证。象Y连接角度和分离差距那样的波导的重要参数被讨论,他们与光力量繁殖和损失特征的关系在这篇论文被调查。优化结构的全部的损失是0.258dB。CLC数字TN252这个工程被基础为武器设备的进展研究节目支持,中国(资助No.02040105DZ02)。
简介:AnartificialdisturbanceisintroducedintotheboundarylayeroveraflatplatetoinvestigatetheeffectonthetransitionprocessintheMach6.5windtunnelatPekingUniversity.Alinearstabilitytheory(LST)isutilizedtopredicttheevolutionoftheeigenmodes,andthefrequencyoftheartificialdisturbanceischosenaccordingtotheLSTresults.Theartificialdisturbanceisgeneratedbyglowingdischargeonthesurfaceoftheplateclosetotheleadingedge.TheRayleigh-scatteringvisualizationandparticleimagevelocimetry(PIV)measurementsareperformed.Bycomparingtheexperimentalresultswithartificialdisturbanceswiththoseunderthenaturalcondition(withoutartificialdisturbances),thepresentpapershowsthatthesecond-modeinstabilitywavesaresignificantlystimulatedbytheartificialdisturbances,andtheboundarylayertransitioniseffectivelytriggered.
简介:Weexperimentallydemonstratea16×16reconfigurablynonblockingopticalswitchfabricusingaBenesarchitecture.Theswitchfabricconsistsof562×2Mach–Zehnderinterferometerbasedelementaryswitches,witheachintegratedwithapairofwaveguidemicroheaters.Theaverageon-chipinsertionlossis~5.2dBforbothofthe'all-cross'andthe'all-bar'states,withalossvariationof1dBoverallroutingpaths.Thecrosstalkforallswitchingstatesisbetterthan-30dB.Theswitchingtimeoftheswitchelementisabout22μs.Theswitchingfunctionalityisverifiedbytransmissionofa40Gb∕squadraturephase-shiftkeyingopticalsignal.
简介:Whenthehigh-pressuregasisexhaustedtothevacuumchamberfromthenozzle,theunderexpandedsupersonicjetcontainedwiththeMachdiskisgenerallyformed.Theeventualpurposeofthisstudyistoclarifytheunsteadyphenomenonoftheunderexpandedfreejetwhenthebackpressurecontinuouslychangeswithtime.ThecharacteristicoftheMachdiskhasbeenclarifiedinconsiderationofthediameterandpositionofitbythenumericalanalysisinthispaper.ThesonicjetoftheexitMachnumberMe=1isassumedandtheaxisymmetricconservationalequationissolvedbytheTVDmethodinthenumericalcalculation.ThediameterandpositionoftheMachdiskdifferswiththeresultsofasteadyjetandtheinfluenceonthecontinuouslychangingofthebackpressureisevidencedfromthecomparisonwiththecaseofsteadysupersonicjet.
简介:阐述了一种由2×2耦合器和3×3耦合器构成的光纤Mach—Zehnder干涉仪(MZI),推导了干涉仪三个输出端光功率的表达式。由于光纤本身的特性,光纤构成的MZI容易受到外界环境的影响,针对这一问题,采用了一种平衡检测相位补偿方法。该方法是通过两个PIN分别对3×3耦合器两路光信号进行接收,并对两路光信号进行差动放大。实验表明该方法可以很好地消除外界环境对MZI干涉效果的影响。
简介:Wepresentanequivalentcircuitmodelforasiliconcarrier-depletionsingle-drivepush–pullMach–Zehndermodulator(MZM)withitstravelingwaveelectrodemadeofcoplanarstriplines.Inparticular,thepartialcapacitancetechniqueandconformalmappingareusedtoderivethecapacitanceassociatedwitheachlayer.ThePNjunctionisaccuratelymodeledwiththefringecapacitancestakenintoconsideration.Thecircuitmodelisvalidatedbycomparingthecalculationswiththesimulationresults.Usingthismodel,weanalyzetheeffectofseveralkeyparametersonthemodulatorperformancetooptimizethedesign.ExperimentalresultsofMZMsconfirmthetheoreticalanalysis.A56Gb/son–offkeyingmodulationanda40Gb/sbinaryphase-shiftkeyingmodulationareachievedusingtheoptimizedmodulator.
简介:Anup-taperedMach-Zehnderinterferometer(MZI)isproposedanddemonstrated.Byapplyingamodificationsettingofanexistingprogramofthefusionsplicer,twoup-tapersarefabricatedbypushingbothsidesofthefibertothemiddle.Itisfoundthatthemaximumextinctionratioreachesupto20dB.Withthefiberlengthof6.3-49cmbetweenthetwoup-tapers,thefreespectralrange(FSR)changesfrom10.7nmto1.3nm.Besides,thewavelengthofmaximumextinctionratioshiftstotheshorterwavelengthinthescopeoftensofnanometers,whiletheelongationchangesfrom0%to0.23%.