提出采用凸形色散平坦光纤(DFF-CVDP)传输亚皮秒啁啾孤子,利用分步傅里叶方法数值研究了亚皮秒啁啾孤子在DFF-CVDP中的传输特性,并与在线性色散平坦光纤(DFF-LDP)中的传输特性做了比较。结果表明,孤子脉冲在上述两种光纤中传输时,光纤损耗导致了孤子脉冲宽度随传输距离增加稍有展宽,脉冲方均根谱宽随传输距离增加逐渐减小。在DFF-LDP中,脉冲展宽更快,正啁啾对脉冲展宽的影响比负啁啾的影响更大,正啁啾对应的方均根光谱比其他情况下的宽得多。啁啾脉冲时域宽度随传输距离增加出现了衰减振荡,振荡周期和振幅随啁啾参量|C|的增加而增大。光孤子脉冲在两种光纤中传输时域波形保持不变,仍具有孤子特性。在DFF-LDP中,β3使得脉冲光谱红移从而诱导了脉冲时延,负啁啾减弱了β3的作用,正啁啾加强了β3的影响。在DFF-CVDP中传输可以忽略β3的影响。

The sub-picosecond chirped soliton propagation is proposed in the dispersion-flatted fiber with convex dispersion profile (DFF-CVDP). Propagation characteristics of the soliton in the DFF-CVDP are numerically investigated by use of the split-step Fourier method, are compared with those in the DFF with linear dispersion profile (DFF-LDP). It is induced by fiber loss that the temporal width of the chirped soliton slightly increases with the increase of propagation distance, the Root-Mean-Square(RMS)spectral width gradually decreases. When the soliton propagates in the DFF-LDP, the soliton broadens faster than that in the DFF-CVDP, effect of positive chirp on pulse broadening is greater than that of negative chirp, the RMS spectrum for positive chirp is wider than those for other cases. The temporal width of the chirped soliton performs a damped oscillation with the increase of propagation distance. The period and amplitude of the oscillation increase with the increase of the chirp parameter |C|. The soliton still maintains soliton characteristics with the hyperbolic secant curve in the two fibers. The time-delay and red-shift of the soliton is induced by the third-order dispersion (β3) in the DFF-LDP. The effect of β3 is weakened by the negative chirp, is enhanced by the positive chirp. The effect of β3 can be neglected in the DFF-CVDP.