折射率导模高双折射光子晶体光纤的偏振特性

本文应用全矢量模型,研究一种折射率导模高双折射光子晶体光纤的特性.重点研究了该种光纤的偏振特性,包括基模场的线偏振特性,模式的双折射及偏振模色散.研究表明,由于在包层中采用两种不同尺寸的空气孔,基模中两个正交偏振模简并被打破,呈现出较高的模式双折射,模式双折射比普通的保偏光纤高至少一个量级,在波长1540nm,其拍长可达0.4067mm.改变光子晶体光纤的结构参数,将获得更高的双折射和更大的群时延差.分析结果与实验测量结果相吻合.

Polarization Properties of Indexing-Guiding Highly Birefringence Photonic Crystal Fibers

Using a full-vector model,we investigate the properties of a kind of high biref ringence index guiding photonic crystal fibers.We concentrate on the polarizatio n properties including linear polarization of fundamental modal field,modal bire fringence and polarization mode dispersion.Two-fold rotational symmetry was int roduced into the fiber structure by creating a regular array of air hole of t wo different sizes disposed about a pure silica core.The degeneracy of two ortho normal polarized-modes of the fundamental mode was removed.This creates a possi bility to attain a modal birefringence of at least one order of magnitude higher than that of conventional high birefringence fibers.A beat length of 0.4067mm i s obtained at the wavelength 1540nm.We can obtain much higher birefringence and larger difference of group time delay by choosing different structure parameter of fibers.The numerical results are in very good agreement with the results of e xperiment.