分类号：O437UDC：密级：公开编号：成都信息工程学院学位论文光纤中脉冲时延对超高斯双脉冲频谱的影响论文作者姓名：申请学位专业：申请学位类别：指导教师姓名（职称）：论文提交日期：光纤中脉冲时延对超高斯双脉冲频谱的影响摘要本文从忽略光纤色散和脉冲间走离效应的的耦合非线性薛定谔方程出发，解析推导了二阶超高斯双光脉冲对的非线性相移，利用傅立叶变换，计算模拟和讨论了不同时延参数下一强一弱的两二阶超高斯脉冲在由于交叉相位调制效应所致的频谱展宽和频谱移动特性随传输距离的变化规律，并与同步输入以及高斯双脉冲的情形作了比较。结果表明：与同步耦合时两束二阶高斯光脉冲对称的频谱特性相比，异步耦合时，两脉冲的频谱是不对称的，要出现频谱移动。时延参数不同，频谱移动的程度及形式也不同；当脉冲1超前于脉冲2时，脉冲1的频谱出现红移，脉冲2出现蓝移；当脉冲1落后于脉冲2时，脉冲1的频谱出现蓝移，脉冲2出现红移。与时延参数为零时相同的是，随着传输距离的增加，频谱宽度变宽，谱峰数目增多。与高斯脉冲的情形相比，在时延参数为零时，超高斯双脉冲能量主要集中频谱中心而不是频谱边缘，在时延参数不为零且其它参数相同时，超高斯双脉冲的频谱比高斯的展得更宽。关键词：交叉相位调制；脉冲时延；超高斯双脉冲，频谱移动Effectsofinitialtimedelayonthefrequencyspectraofthesuper-GaussianopticalpulsepairsinopticalFibersAbstractStartingfromthecouplednonlinearSchrödingerequationwheretheeffectofwalk-offbetweenpulsesanddispersioneffectareneglected,thenonlinearphaseshiftsofthesecond-ordersuper-Gaussianpulsepairareanalyticallydeduced.AndutilizingtheFouriertransformation,thevariationsofpowerfrequencyspectraoftwosecond-ordersuper-Gaussianpulses(oneisstrongandanotherisweak)withthedistancefordifferentinitialtimedelayparametersarecomputersimulatedanddiscussed.AndcomparisonsarealsomadewiththecaseofsynchronousinputtingandGaussianpulsepairs.Theresultshowthat,comparingwiththecaseofsynchronouscouplingwherethepowerspectraofthetwopulsesaresymmetric,thepowerspectrabecomeunsymmetricalincaseofasynchronouscouplingandthespectralshiftingwilloccur.Dependingondifferenttimedelayparameter,thespectrawillshifttodifferentdegreeandindifferentways.Whenthefirstpulseisinputbeforethesecondone,theredspectralshiftandblueshiftwillappearforthefirstandsecondpulse,respectively.Otherwise,theoppositewilloccur.Withincreaseofthedistance,thespectrawillbecomewideandappearmorespectralpeaks.IncomparisonwiththecaseofGaussianpulsepairs,whenthetimedelayparameteriszero,super-Gaussianpulsesmainlydistributetheirenergyinthecentreinsteadofintheedgyofthespectra.Whilewhenthetimedelayparameterisnotzeroandtheotherparametersarethesame,thespectraofsuper-GaussianpulseswillbewiderthanthoseofGaussi