余弦-超高斯脉冲的演化特性研究

本文研究了余弦-超高斯(CSG)脉冲在光纤中的演化特性并对CSG脉冲在光纤中的传输过程进行了数值研究。得到了脉冲的初始相位φ0和脉冲阶数m对脉冲传输过程及其演化规律的影响。结果表明，增大φ0值到80 rad时的一阶余弦-超高斯脉冲可以在相对较长的光纤中实现脉冲压缩；而高阶余弦-超高斯脉冲在经历较短的脉冲压缩后，随即展宽。脉冲阶数越高，其脉冲压缩所经历光纤长度越短。本文还将余弦-超高斯脉冲、简单高斯脉冲和双曲正割脉冲进行对比，对比结果表明双曲正割脉冲展宽速度最快，简单高斯脉冲次之，而余弦-超高斯脉冲的展宽速度最慢。所提出的余弦-超高斯脉冲对光纤色散不敏感，该研究对于实际中要得到大容量，长距离通讯用的特殊脉冲的研究提供了一定的理论依据。

Investigation of the cosine-super Gaussian pulses evolution

The evolution of cosine-super Gaussian (CSG) pulses propagating in a conventional single mode fiber (SMF) has been proposed. The propagation properties of CSG pulses are numerically studied by using split-step Fourier method, and the effects of initial phase φ0 and order of the pulse m are analyzed. Results show that when φ0 is increased to 80 rad, the first order CSG pulse will be compressed in a relatively long fiber, and then broaden monotonically; the higher order CSG pulses will experience a short compression first, and then broaden monotonically. In addition, the CSG pulses are compared with simple Gaussian pulses and Hyperbolic secant pulses. The results indicate that the Hyperbolic secant pulse broaden fastest; the simple Gaussian pulse broaden secondly; CSG pulses broaden slowest, which is most insensitive to the dispersion of fiber. The research work will pave a way to realize a special pulse in large-capacity, and long-range communications.