Eguchi Masashi, Horinouchi Suguru
Chitose Institute of Science and Technology, Chitose, Hokkaido 066-8655, Japan.
Appl Opt. 2004 Apr 1;43(10):2163-7. doi: 10.1364/ao.43.002163.
Plastic optical fibers that are a typical large-core multimode optical fiber support a great number of modes compared with conventional silica-glass multimode optical fibers. So far the WKB method hasbeen used for most of the modal analyses of these fibers because of a great number of guided modes. We describe the accurate eigenmodal analysis of large-core multimode optical fibers with the finite-element method (FEM) and compute the propagation constants of all LP modes. In addition, the FEM has a strong advantage for arbitrary core profiles whereas the WKB method is not suitable fornonmonotonic profiles. To demonstrate the advantage, we apply the FEM to the fiber having sinusoidal fluctuations.
塑料光纤作为一种典型的大芯径多模光纤，与传统的石英玻璃多模光纤相比，支持大量的模式。到目前为止，由于存在大量的导模，WKB方法已被用于这些光纤的大多数模态分析。我们用有限元法（FEM）描述了大芯径多模光纤的精确本征模态分析，并计算了所有LP模式的传播常数。此外，有限元法对于任意纤芯轮廓具有很大优势，而WKB方法不适用于非单调轮廓。为了证明这一优势，我们将有限元法应用于具有正弦波动的光纤。
