【摘要】 本文应用有限元方法 ,求解了任意径向非均匀折射率分布圆柱对称介质波导中纵向场耦合波动方程定解问题所对应的变分问题 ,计算了任意径向非均匀折射率分布介质波导的截止波长。阶跃光纤与幂指数折射率分布光纤计算结果与文献结果的比较表明 ,该方法计算结果精度高且不需要弱导或高斯模场分布等限制要求。然后本文研究了带阶跃环的三角型分段折射率分布光纤归一化截止频率随结构参数变化的规律。更多还原

【Abstract】 The variational problem related to the coupled vector wave equations and boundary conditions of circular dielectric wave guide with arbitrary refractive index profile is solved by using the finite element method(FEM) The cutoff wavelengths for step index and power law refractive index profile optical fiber are calculated and compared with the results of former studies with different methods The comparison shows that without any limitation of weakly guiding or Guass Mode field distribution to the dielectric waveguide we can easily calculate the cut off wavelengths for different refractive index profile optical fiber with high precision Then the cutoff properties of triangular segmented core with step ring optical fiber have also been studied更多还原