分类号：UDC：密级：公开编号：成都信息工程学院学位论文数值研究光纤中啁啾高斯光脉冲的频谱演化论文作者姓名：申请学位专业：光信息科学与技术申请学位类别：理学学士指导教师姓名(职称)：论文提交日期：2009年06月01日数值研究光纤中啁啾高斯光脉的冲频谱演化摘要本文从光纤中的非线性薛定谔方程出发，采用分步傅立叶算法，分光纤的正色散区和负色散区两情况，数值模拟了啁啾高斯光脉冲频谱随传输距离、脉冲初始啁啾参数的变化规律。结果表明：在正色散区，初始啁啾为负时脉冲频谱会经历一个初始窄化过程，即先窄化再展宽，初始啁啾绝对值越大，脉冲窄化程度越大，达到最佳窄化时所需光纤长度越短。无初始啁啾时脉冲频谱是随着传输距离的增加慢慢展宽的，而正的初始啁啾对频谱影响不大。在负色散区，当初始啁啾为正时，脉冲频谱会经历一个初始展宽过程，即先展宽后窄化，正初始啁啾越大，脉冲频谱展宽越大，达到最佳展宽所需光纤长度越短。而负的初始啁啾将加速频谱窄化，负的啁啾参量越大，窄化速度越快。当无啁啾时，脉冲频谱也是随着传输距离的增加而压缩，这点与正色散区时不同的。关键词：非线性光学；啁啾高斯光脉冲；非线性薛定谔方程；分步傅立叶算法NumericalstudyonspectrumevolutionofchirpedpulseGaussianinanopticalfiberAbstractStartingfromthenonlinearSchrödingerequationandadoptingthesplit-stepFouriermethod,thevariationoffrequencyspectrumofGaussianopticalpulsewiththepropagationdistanceandtheinitialfrequencychirpisnumericallysimulatedinboththenormalandanomalousdispersionregimesintheopticalfiber.Theresultsindicatethat,inthenormaldispersionregime,whentheinitialchirpisnegative,thepulsefrequencyspectrumwillexperienceaninitialnarrowingprocess.Thatistosay,thespectrumwillbecomenarrowafterbroadening.Thegreatertheabsolutevalueoftheinitialchirp,thegreaterthedegreeofspectrumnarrowingandtheshorterthefiberlengthrequiredtoachievethebestcompression.Whenthepulseischirp-free,itsspectrumwillbroadenwithincreaseofthepropagationdistance.Whilethepositivechirphardlyinfluencethespectrum.Whileintheanomalousdispersionregime,thepulsefrequencyspectrumwillexperienceaninitialbroadeningprocess.Thatistosay,thespectrumwillbroadenafternarrow.Thegreatertheabsolutevalueoftheinitialchirp,thegreaterthedegreeofspectrumbroadeningandtheshorterthefiberlengthrequiredtoachievethebestbroadening.Andthenegativeinitialchirpmayspeedupthespectrumnarrowing.Whenthepulseischirp-free,itsspectrumwillnarrowwiththedistancealltheway,whichisdifferentfromthecaseinthenormaldispersionregime.Keywords:nonlinearoptics;chirpedGaussianopticalpulse;nonlinearSchrödingerequation;thesplit-stepFouriermethod目录论文总页数：21页TOC\o"1-3"\h\z\uHYPERLINK\l"_Toc137462423"1