等效电流方法计算单模光纤的辐射损耗

本文将无源的不规则波导看作有源的理想波导,求等效极化电流电场,直接得到单一光波导模间耦合和辐射损耗问题的解。用这个方法计算了阶跃单模光纤折射率轴向不均匀变化的损耗。这种方法完全脱离了耦合波的概念,它不但物理意义明确,而且求解问题的方法简洁。最后以单模光纤弯曲和微弯损耗为例,说明等效电流方法还适用于广义耦合波理论才能求解的问题。

Calculation of radiation loss in single mode fibers by equivalent current method

Taking a non-ideal waveguide as an ideal waveguide in the presence of polarization currents giving rise to electric and magnetic fields, we can directly solve the problems of mode coupling and radiation loss of an optical waveguide. By using this method, we have calculated the radiation loss of single mode fibers caused by periodical and random non-uniformities of the core index. It is an alternative method of coupled mode theory, but is mathematically impler and physically more intuitive than the coupled mode theory. At last, taking bending and microbending loss for single mode fibers as an example, we see that this method also applied to problems which can be solved by generalized coupled mode theory.