一种金填充高双折射光子晶体光纤偏振滤波器

摘要

为了获得具有对称性结构的金填充高双折射光子晶体光纤,采用有限元方法对光纤的纤芯基模、金属表面等离子体激元的色散和损耗特性进行了分析. 改变包层晶格节距、纤芯周围气孔直径以及填充金丝直径能够灵活地调节纤芯基模与等离子体激元之间共振响应波长点的位置和耦合强度. 通过对光纤结构参量的优化,获得了一种基于通信波段的偏振滤波器. 当特定空气孔数值孔径确定后,在1.55μm处, x方向基模损耗可以达到473dB/cm,而y方向基模几乎不会受到等离子体激元的干扰. 结果表明,与单偏振单模光子晶体光纤相比,新设计的光纤结构可以通过调节金丝直径大小,选择性地滤掉某一偏振方向的光,从而达到在通信波段滤波的效果. 该研究对研制基于通信波段的偏振滤波器具有一定的参考意义.%In order to obtain symmetrical high birefringence photonic crystal fiber filled with Au .The fundamental mode of the fiber core, dispersion and loss characteristics of plasma polaritons of metal surface were analyzed by means of finite element method.The resonance positions and the resonance strength between fundamental mode and plasma polaritons could be well adjusted by changing the distances between the cladding air holes , the diameters of air holes around the core and the diameter of metal wire.By optimizing the parameters of fiber structure , a polarization filter at the communication band was designed .After numerical aperture of air hole was determined , fundamental mode loss in x-position could reach 473dB/cm and fundamental mode loss of y-position was almost not affected by surface plasma polariton (SPP) mode at the wavelength of 1.55μm.The results show that compared with ordinary single-polarization and single-mode photonic crystal fibers , the polarized light in one direction can be filtered out selectively by adjusting the wire diameter and achieve filtering effect in the communication band .It is meaningful for the development of polarization filters in the communication band .