阶跃折射率光纤TE_(01)模衍射场的光束传输因子

The Beam Propagation Factor in Diffracted Field of TE_(01) Mode in Step Index Fiber

根据阶跃折射率光纤TE01模的模场分布及模场径向空间频谱分布与模场分布的关系,给出了阶跃折射率光纤TE01模的二阶矩模场半径和径向空间频率半径以及衍射场光束传输因子的解析函数表达式.计算表明,当光纤归一化频率大于2.797 4时,阶跃折射率光纤TE01模衍射场的光束传输因子较接近于2.采用多项式拟合光束传输因子与光纤归一化频率的关系,给出了光束传输因子与光纤归一化频率关系的函数表达式,并基于拟合值和计算值之间的相对误差阐明了拟合函数表达式的精确性.

Based on the mode field distributions and the relationship between the radial spatial spectrum and the mode field distributions of the TE01 mode in step index fiber, the expressions of the mode field radius and the radial spatial frequency radius by second moment algorithm and the beam propagation factor of diffracted field are derived. Numerical calculation shows that the beam propagation factor of the TE01 mode is close to 2 when the normalized frequency is greater than 2. 797 4. The fitting expression between the beam propagation factor and the normalized frequency is given by curve fitting, the accuracy of fitting expression is show by the relative error between the fitted value and the calculated value.