初始啁啾对单模光纤中超高斯脉冲传输特性的影响

Influence of initial chirp on the propagation properties of super-Gaussian pulses in the single-mode optical fibers

从非线性Schr(o|¨)dinger(NLS)方程出发,采用变分法,导出了单模光纤中超高斯脉冲参数随传输距离的演化方程组,求出了振幅与脉宽、频率与啁啾、脉宽与啁啾之间的三个解析约束关系,得出了脉宽随传输距离演化的解析解,用龙格-库塔法进行数值求解描绘了初始啁啾和脉冲前后沿锐度对单模光纤中超高斯脉冲脉宽的影响。结果表明:初始啁啾和脉冲前后沿锐度对超高斯脉冲的振幅、脉宽、啁啾和相位有直接影响,超高斯脉冲传输过程中会产生啁啾,但脉冲中心的等效频率保持为常数。

Based on the NLS equation and variational method, the evolution equations for the parameters of the super-Gaussian pulse in single-mode optical fibers are deduced. Then three restricted relations between amplitude and width, frequency and chirp, width and chirp are derived. Analytical solution about the width of pulse evolves on the propagation distance is obtained. By using Runge-Kutta algorithm, the influences of the initial chirps and the degree of the pulse＇s edge sharpness on the pulse width are described. The result indicates that initial chirps and the degree of the pulse＇s edge sharpness have effect on amplitude, width, chirp and phase, and super-pulse has a chirp in the process of transmission, but the pulse centre equivalent frequency maintains a constant.