非均匀光纤中色散特性的研究

本文研究在非均匀光纤传输系统中,周期性材料色散扰动对光脉冲的影响,并且建立了正弦型均匀扰动模型．利用傅立叶变换法,分别推导了非均匀光纤传输系统中,二阶色散系数受周期性扰动时,无啁啾高斯型光脉冲受二阶色散;二阶和三阶色散共同决定群速度色散效应时,脉冲传输的解析表达式．并在理论上阐述了波形变化．波形显示:对于无啁啾的高斯光脉冲,当扰动程度和扰动周期很大时,二阶色散使脉冲在开始阶段有一个窄化过程,脉冲峰值变高,脉宽被明显压缩;对于二阶和三阶共同作用时,脉冲不仅产生拖尾震荡结构,而且脉冲的震荡沿上翘.当扰动程度和扰动周期很大时,在开始阶段脉冲被压缩,波形发生变化．本文的研究对光纤周期性色散材料对光脉冲的影响有重要的意义．

THE RESEARCH OF CHROMATIC DISPERSION CHARACTERISTIC IN INHOMOGENEOUS OPTICAL FIBER

In this article, the influence of the periodical perturbation of material chromatic dispersion to light pulse in inhomogeneous optical fiber transmission system was studied and the sine isotropic turbulence model was established. Using the method of Fourier transformation, we deduced the analytic expression of the pulse transmission respectively when the group velocity chromatic dispersion effect of non - twitter Gaussian light pulse are decided by two step chromatic dispersion, two step and three step chromatic dispersion together when two step dispersion coefficient is disturbed periodically in the inhomogeneous optical fiber transmission system. At the same time, we describe the change of wave shape theoretically. The wave shape shows that as for as non - twitter Gauss light pulse, when the perturbation degree and the perturbation cycle are very big, two step chromatic dispersion makes the pulse have a narrow process in the initial stage, the pulse peak value becomes high, and the pulse width is compressed obviously. When regarding two step and three step chromatic dispersion act together, not only the pulse produces the trailing shake structure but also the pulse shake curls upwards along on. When the perturbation degree and the perturbation cycle are very big, the pulse is compressed in the initial stage and the wave shape will change. The research in this paper has the vital significance to the optical fiber periodic chromatic dispersion material to affect the light pulse .