说明：  画出光纤的色散曲线 首先对色散的拟合曲线做了一个循环，计算出误差最小的曲线拟合阶数，而后进行色散曲线拟合，画出拟合曲线
(Draw the fiber dispersion curve of the first curve fitted to the dispersion to make a loop, the error is calculated minimum order curve fitting, then, dispersion curve fitting, curve fitting draw)