【摘要】 非线性薛定谔方程是光脉冲在光纤中传播时所遵循的基本方程.本文利用分步傅里叶方法从数值结算的角度研究了具有线性啁啾的光脉冲在具有横向增益光纤中的自相似传播特性.研究表明:当群速度色散系数和光脉冲的啁啾系数符号相同时,由于在传播过程中自相位调制和群速度色散分别起主要作用,不论何种形式的光脉冲在传输过程中均会受到压缩,但随着传播距离的增加压缩的光脉冲会展宽;埃尔米特高斯输入和正弦输入在传播过程中的光强分布是对称的,拉盖尔高斯输入在传播过程中会发生能量交换而表现出明显的偏转;当群速度色散系数和光脉冲的啁啾系数符号不相同时,在传播过程中群速度色散始终起主要作用,脉冲一直展宽.这些研究结论可能为未来光纤压缩器、光纤放大器以及新型THz调制波源的制备提供新的理论基础和方法.更多还原

【Abstract】 Nonlinear Schrdinger Equation is a basic equation for investigating the propagation of optical pulses in fibers.By using the split-step Fourier method,self-similar propagation of linearly chirped pulses in fibers with longitudinal gain profile is studied.It is found that,because the self-phase modulation and group velocity dispersion respectively play the main roles at different propagation distances when the signs of the group velocity dispersion coefficient and the chirp coefficient are the same,no matter what the shapes of the input pulses are,the pulses will be compressed during propagation,and with the further increasing of the propagation distance,the compressed pulses will be broadened again.The intensity distributions of the Hermite-Gaussain input pulse as well as the sine input pulse are symmetric,while that of the Laguerre-Gaussian input pulses deflect during propagation obviously because of energy exchange.When the signs of the group velocity dispersion coefficient and the chirp coefficient are different,group velocity dispersion plays the main role,and the pulse is always broadened during propagation.The results may provide a new theoretical foundation and a new method for the fabrication of pulse compressors,amplifers and the development of a new source for THz modulated beams.更多还原