简介：WepresentthefirststepsofadesignoftheoptimalparametersforafullBraggX-Rayfreeelectronlaser(BX-FEL).AimingtowardsafuturesourceofcoherentX-rayradiation,operatinginthestrongComptonregime,weenvisagethesystemtobetheseedforanadvancedlightsourceorcompactmedicalX-raysource.Herewefocusonthedesignoftheacceleratorparameters:maximumgradient,optimalacceleratedcharge,maximumefficiency,and‘wakecoefficient’,whichrelatestothedeceleratingelectricfieldgeneratedduetothemotionofacharged-lineortrainofcharged-lines.Specifically,wedemonstratethatthemaximumefficiencyhasoptimalvalueandgiventhefluenceofthematerials,themaximumacceleratedchargeinthetrainisconstant.Thesetworesultsmightbeimportantinanyfuturedesign.

简介：Waveenergyhasdrawnmuchattentionasanachievablewaytoexploittherenewableenergy.Atpresent,inordertoenhancethewaveenergyextraction,mosteffortshavebeenconcentratedonoptimizingthewaveenergyconvertorandthepowertake-offsystemmechanicallyandelectrically.However,focusingthewavepowerinspecificwavefieldcouldalsobeanalternativetoimprovethewaveenergyextraction.Inthisexperimentalstudy,theBraggresonanceeffectisappliedtofocusthewaveenergy.BecausetheBraggresonanceeffectoftherippledbottomlargelyamplifiesthewavereflection,leadingtoasignificantincreaseofwavefocusing.Achievedwithanenergyconversionsystemconsistingofapointabsorberandapermanentmagnetsinglephaselinearmotor,thewaveenergyextractedinthewaveflumewithandwithoutBraggresonanceeffectwasmeasuredandcomparedquantitativelyinexperiment.ItshowsthatenergyextractionbyapointabsorberfromastandingwavefieldresultedfromBraggresonanceeffectcanberemarkablyincreasedcomparedwiththatfromapropagatingwavefield(withoutBraggresonanceeffect).

简介：ThecalculationprincipleofsampledFBG,whichiscalledtransfermatrixmethod,isanalyzedandthesimulationsoftwareisdesigned.ThesampledFBGissimulatedwiththesoftwarewedesignedandisfabricatedbyourselves.Theexperimentresultfitswellwiththesimulatedone.ItisconcludedthattoimprovetherefractivemodulationindexisaneffectivewaytofabricateasampledFBGwithhigh-reflectivity.

简介：我们建议一个硅石核心模式的减少分散的布拉格纤维(DDBF)象55渭m一样大的有效区域2为supercontinuum(SC)在1060nm的泵波长的产生。用到在DDBF的模型繁殖的一个快、简单的矩阵方法，我们介绍了一个一般标准获得将导致一个宽广SC系列的DDBF的最短的长度。建议DDBF设计应该为通过生产技术的开发得好的MCVD纤维的可再现的制造是顺从的，这个概念作为一台实际设备为实现有潜力。CLC数字TN818文件代码A

简介：ExperimentsareperformedinawaveflumetodemonstratetheBraggreflectionoflineargravitywavesbyartificialbars.Threedifferentartificialbarswithrectangular,triangularandrectifiedcosinoidalshapesareplaceddiscretelyontheseabedformeasurementoftheBraggreflection.Aseriesofexperimentalconditionsincludingthenumberofbars,thepe-riodicbarspacing,thewaterdepthandvariouswaveconditionsaretested.KeyparametersinfluencingtheBraggreso-nancesareinvestigated.Theexperimentaldataarecomparedwiththevaluesfromboththeoreticalandnumericalmodels.Somekeyparametershaveprovedtobeeffectiveindescribingtheprimaryresonances.Predictiveequationsofthecharac-teristicsfortheBraggreflectionareproposedinthispaper.

简介：A2-cmlongBragggratingwithreflectivityof～99.95%inB/Gecodopedopticalfiberwithouthydrogenloadingwascreatedbyphase-maskmethodwithapulsedKrFexcimerlaserat248nm.DCandACcomponentsofrefractiveindexchangewereanalyzedbymonitoringtransmissionspectrumevolutionduringthewritingprocessoffiberBragggrating.Therelationsoftheevolutionofcenterwavelengthandreflectivitywithnumberofpulseswererespectivelyinvestigated.

简介：MultiwavelengthchirpedfiberBragggrating(MCFBG)isamorevaluableapproachtochromaticdispersioncompensation.AndadjustingthestructureofFBGwilloptimizetheperformanceofdispersioncompensatorin8×10Gb/sDWDMnetwork,whichisprovedbysimulatingcalculation.

简介：SpectralandstructuralcharacteristicsofdistributedBraggreflector(DBR)invertical-cavitysurface-emittinglaserswerestudiedwithphotoluminescenceanddouble-crystalX-raydiffractionmeasurement.TheexpectedhighqualityepitaxialDBRstructurewasverified.IntheX-raydouble-crystalrockingcurvesofDBRthezeroth-orderpeak,thefirstandsecondordersatellitepeaksweremeasured.Splittingofdiffractionpeakappearedintherockingcurveswasanalyzed.Theeffectsofintroduceddeepenergylevelsonthestructuralperfectionandopticalpropertieswerediscussed.

简介：Inthispaper,theangularspreadoftheSAWbeamdiffractedbyBragggrating,denotedbyδθ1,isana-lysedbasedontheequationsofthedeflectionangleandthedeflectioneffciency.AparameterδθBisde-finedtoreferto"Braggangularspectrumwidth"ofthegrating.Theimportanceofthisparameterindis-tinguishingtheangularspreadrangeofthedeflectedbeamfordifferentregimesisdiscussedaswell.Itisshowfromtheanalysisthatifthespreadangleoftheincidentbeamlabelledwithδθincislargethanthe"Braggwitdthoftheangularspectrum"ofthegrating,thespreadangleδθ1ofthedeflectedbeamwillequaltoδθB;butiftheangulardivergenceoftheincidentbeamislessthanδθB,thenδθ1=δθincExperimentally,fourkindsofsampleswithdifferentconfigurationsareinvestigatedbyopticalmethod,twoofwhichoperateintheregimeofδθinc<<δθBandtheotherscorrespondtothecaseintheregimeofδθinc>>δθB.Thewidthsoftheangularspreadoftheinciden

简介：这篇论文论述平面纤维布拉格栅栏(FBG)水中听音器探查察觉到原则，并且理论上并且试验性地研究探查结构敏感，收到的敏感频率反应特征和加速反应性质。平面表用不锈钢做的，它的厚度是0.15公羊，它的直径是空圆形的壳的15mm，和长度是20公羊。为结构的这种尺寸，探查结构敏感直到23fm/Pa，它是大约7300次赤裸的纤维的价值。回声频率是6.5kHz，和反应是的收到的敏感的振幅频率曲线相对在到5.5kHz的100Hz的频率范围以内的命令。一单位加速(1m/s2)产出的产量等价于(2.52～3.26Pa)声学的压力代理输出。这探查结构是容易的由multiplexingtechnique.The研究表演形成FBG水中听音器数组这平面结构能不仅形成FBG水中听音器探查，而且能组成光FBG激光水中听音器探查。结构能认识到不同带宽，不同范围由调整表的几何尺寸的声学的压力测量。

简介：Directcalculationsofabsorptionspectraformulti-quantumwellstructuresbyextractingfielddistributionsatwellpositionsareperformed.ResultsdemonstratethepreviouslyreportedBraggsuppression,andagreeexactlywiththeindirectcalculationbylineardispersiontheory.ThisrevealsthatBraggsuppressioneffectinfactoriginatesfromtheremarkablydecreasedintensitiesatwellpositionsbyBragginterferencecondition,ratherthanfromtheformationofsupperradiantmodes.

简介：Few-modefiberBragggrating(FM-FBG)haswideapplicationsinthefieldofmulti-wavelengthfiberlasersandfiber-opticsensing.Inthisletter,FBGissuccessfullywritteninanoveltypeofFMfiber(FMF)basedon248-nmexcimerlaserandauniformphasemask.Alow-losscouplingbetweentheFMFtoasinglemodefiberisrealizedbyagraded-indexmulti-modefiberwithalengthofaboutaquarterpitch.ThesensingpropertiesoftheFMFgratingarefurtherinvestigated.TheexperimentalresultsindicatethatthenovelFM-FBGhassensitivitiesoftemperature,strain,andbendingof11.2pm/C,1.3pm/με,and636.9pm/m1,respectively.

简介：AnoveltunablechirpedfiberBragggratingtechnologyisproposedandsimulatednumericallybyMatlab.Ifweadhereauniformfibergratingwithsupermagnetostrictivefilmandexposetheminanon-uniformmagneticfield,theperiodofthegratingcanbechangedwiththestrainimposedonitbythemagnetostrictiveeffect.Thechirpedcharacteristicscanbetunedbychangingthemagneticfiledwhichisveryflexibleindesigning.

简介：AkindoffiberBragggratingpressuresensorbasedoncorrugateddiaphragmisproposed.TherelationshipbetweenthecentralwavelengthofreflectivewaveofFBGandpressureisgiven,andtheexpressionofthepressuresensitivitycoefficientisalsogiven.Withintherangefromresultsagreewiththetheoreticalanalysis.Itisindicatedthattheexpectedpressuresensitivityofthesensorcanbeobtainedbyoptimizingthesizeandmechanicalparametersofthecorrugateddiaphragm.

简介：当它在察觉到的fiberBragg栅栏(FBG)被使用时，波长部门multiplex有明显的优点因为各种各样的数量的同时的测量，而是传感器的数字被小橇和解调器的带宽通常限制。相同纤维Bragggrating为火报警系统被介绍，收集相同FBGsensors的信号的方法被描述。实验结果显示出那，相同FBG察觉到。传感器的数字极大地在一纤维增加联合了，精确能被保证为火报警系统满足要求。

简介：TheshearlagtheoryisusedtoanalyzethestresstransferfromconcretematrixtoFBGsensorsbasedonthattheFBGsensorandtheconcretematrixarecomposite.Thestresstransferformulaandthecoefficientareobtained.Theexperimentsprovethatthetheoreticalresultsofthestresstransferbythestresstransferformulaareinwellagreementwiththeexperimentaldata.

简介：

简介：Oneofthemostbasiccharacteristicsofphotoniccrystalisfrequencybandgap.Whendefectsareintroducedintotheperiodicphotoniccrystal,anumberofdefectmodesappearinthestopband.Inthispaper,weexploittransfermatrixmethodbasedonphotoniccrystaltheory,andassumethesampledfiberBragggratingasone-dimensionaldualphotoniccrystalwithalargesizedefect.CharacteristicsofthesampledfiberBragggratingareanalyzed.ExperimentalresultsshowthatthesampledfiberBragggratinghasmanyreflectivepeaks.Itsreflectivity,centerwavelength,reflectivepeakintervalsandbandwidthallchangewiththegratingparameters,includinggratinglength,dutyratioofthematerialwithhighdielectricconstant,andindexmodulationdepthandperiod.Resultsagreewiththeconventiona1couplemodetheorywhichcanbeusedwhenanalyzingothercharacteristicsofthesampledfiberBragggratingorapplyingitintopractice.

简介：TheshiftmechanismofBraggwavelengthwithstressvariationforafibergratingisinvestigatedindetail.Theinfluenceofstrainchangeonreflectionandbandpassistheoreticallyanalyzed.Byapplyingstress,thedynamicsingle/dual-channelfilterwithtunablefiberBragggratingsisachieved.

简介：ThemethodtopumptheFBGwrittenintoanEr3+-dopedopticalfiberisproposedtoincreasethegroupvelocityofaprobingpulsebasedonthefactsthatpump-inducedprocesschangestherefractiveindexanddispersionassociatedwiththe4I15/2-4I13/2transitioninEr3+-dopedopticalfiber.Thesystemequationsarederived.Theeffectsofpumppoweranddopingconcentrationonthegroupvelocityarediscussed.