光纤波导传光模式及其特性

Optical Fiber Waveguide Transmission Modes and Their Characteristics

将光纤波导内矢量场经简并处理后转化为波导内的线偏振模式,求解柱面坐标系下标量场的波动方程,得到线偏振模式的贝塞尔特征方程;利用线偏振模式的贝塞尔函数解,模拟光纤波导横截面场强分布,分析场强分布特征。结果表明:线偏振模式的贝塞尔特征方程决定了线偏振模式的截止、远离截止条件,特征方程还包含传播系数,特征方程的这些属性显示在各自的曲线图中,进一步确定光纤波导内的传播模式及其基本特征、单模传输条件,所得结果与波导内矢量精确场相匹配;线偏振模式的场强分布模拟结果与贝塞尔函数曲线的截止、远离截止,与传播系数曲线分析的传播模式特征完全吻合,结果更直观,特征更明显。

Vector fields in optical fiber waveguide were transformed into linearly polarized modes after degeneracy.By solving the wave equation of scalar fields in cylindrical coordinate,Bessel characteristic equation of linearly polarized modes was obtained.By using Bessel function solutions of linearly polarized modes,cross section field intensity distribution of the fiber waveguide was simulated,and field intensity distribution characteristics were analyzed.The results show that Bessel characteristic equation of linearly polarized modes determines conditions of cutoff and far away from cutoff of linearly polarized modes,and the characteristic equation also contains propagation coefficients.All these properties of the characteristic equation display in their respective graphs.The wave propagation modes and their basic characteristics,as well as single-mode transmission conditions in the optical fiber waveguide can be further determined,and the results match with precise fields in the waveguide.Field intensity distribution simulation results of the linearly polarized modes are well consistent with the cutoff and far away from cutoff properties of Bessel function curves,and also with propagation mode characteristics of propagation coefficient curve analysis.The simulation results are more intuitive,and the characteristics are more obvious.