级联单模光纤中初始啁啾对高阶孤子脉冲压缩的影响

采用两段级联单模光纤对高阶孤子脉冲进行压缩。两段光纤具有不同的反常色散值,当高阶孤子脉冲在第一段光纤中获得最大程度压缩时,通过转换色散值不同的光纤,使压缩脉冲继续以高阶孤子的形式在第二段光纤中再次被压缩。每段光纤的长度都进行了优化,使得脉冲在每段光纤中都获得最大程度的压缩。基于非线性薛定谔方程,数值研究了初始啁啾对高阶孤子脉冲压缩的影响。研究结果表明,初始啁啾对高阶孤子脉冲的压缩有重要影响。与无初始啁啾时的情形相比,正的初始啁啾能增强每段光纤中脉冲的压缩效果,降低压缩脉冲的基座能量,而负初始啁啾的影响则相反。随着初始啁啾参量Cp的增大,脉冲在每段光纤中的压缩因子均增加,而基座能量、最优光纤长度均减小。

Effect of Initial Frequency Chirp on Pulse Compression of Higher-order Solitons in Cascaded Single-mode Fibers

We consider the pulse compression of higher-order solitons in two cascaded single-mode fibers. The two single-mode fibers have different anomalous dispersion value. When the higher-order soliton pulse achieves maximal compression in the first fiber, by switching the fiber with different dispersion, the pulse is compressed again as a new higher-order soliton in the second fiber. Each fi-ber length is optimized in order to achieve maximal compression inside each fiber segment. Based on the generalized nonlinear Schr?dinger equation, we numerically study the effect of initial frequency chirp on pulse compression of higher-order solitons. Our numerical results show that initial frequency chirp has significant influence on higher-order solitons pulse compression. In comparison with the case of without initial chirp, a positive chirp can enhance the pulse compression and can reduce the pedestal energy in each fiber segment, while a negative chirp does the opposite. In each fiber seg-ment, as the chirp parameter Cp increases, the compression factor increases, while pedestal energy and optimal fiber length decrease.