具有啁啾的任意脉冲在弱非线性色散光纤中的演化  

The Evolution of Pulse of Arbitrary Initial Form with Chirp in Weakly Nonlinear Dispersive Fiber

作　　者：吴重庆[1] 赵宏静[1] 王智[1] 刘艺[1] 

机构地区：[1]北方交通大学

出　　处：《铁道学报》1997年第4期60-66,共7页Journal of the China Railway Society

基　　金：国家自然科学基金

摘　　要：随着线性色散补偿技术的成熟，光纤通信的另一个限制因素——非线性，将随着光纤链路的加长而积累起来。就每一段光纤而言，均属弱非线性的色散光纤，因此，有必要对光脉冲在这种光纤中的演化进行深入研究。本文首次得出非线性薛定谔方程（ＮＳＬ方程）的频域级数解，它适用于具有初始啁啾的任意脉冲。结果表明：频谱的演化由两部分组成，一部分是将非线性引起的频谱展宽集中于始端，并将这个频谱展宽了的信号在线性色散光纤中传输；另一部分是为保证始端脉冲频谱满足初始条件的补偿项。首次得出前述光纤中只考虑一阶初始非线性有啁啾的高斯脉冲的频谱与波形的演化情况，并得出无啁啾高斯脉冲的展宽因子的近似公式，结果表明非线性的贡献与β２的符号有关，反常色散光纤（β２＜０）可使脉冲展宽减弱。文中还给出了频谱、波形、展宽因子等随距离、色散。With the success in linear dispersion compensation technique in optical fiber communication,a new limitation with nonlinearity will be accumulated when the length of fiber link increases.Because the nonlinearity in every section of fibers is weak,it is necessary to deeply study the evolution of optical pulse in the weak nonlinearity dispersive fiber. In this paper,we firstly get the series solution in the frequency domain,suitable for pulses of arbitrary initial form with chirp.The result shows that the development of spectrum consists of two parts:one is the spectrum of a signal which propagates in a linear dispersive fiber from the origin with the broadening spectrum produced by nonlinearity,the other is the compensative term which is used to make the initial spectrum of pulse meeting the initial condition. We get the evolution of spectrum of Gauss pulse with chirp in this fiber when only consider the first order initial nonlinearity,and obtain the approximate formula of the broadening factor without chirp.It shows that the contribution of nonlinearity to it is related to the sign of β 2 and the positive dispersive fiber ( β 2<0) can make the broadening of pulse weak.Finally, the figures of spectrum,pulse form and broadening factor versus distance,dispersion, nonlinearity and chirp are given.

关 键 词：非线性色散光纤 啁啾 高斯脉冲 光纤通信 

分 类 号：TN929.11[电子电信—通信与信息系统]