基于椭圆孔包层和微型双孔纤芯的新型高双折射光子晶体光纤

Novel Highly Bireferingent Photonic Crystal Fiber Based on an Elliptical Hole Fiber Cladding and a Fiber Core of Double-micro-hole Units

设计了一种新型高双折射光子晶体光纤,即其包层引入椭圆形空气孔,且以三角晶格方式周期排列,纤芯引入亚波长尺寸(～0.16μm)的微型双孔结构阵列.采用全矢量有限元法和各向异性完美匹配层边界条件分析了该型光子晶体光纤的双折射特性和色散特性,详细介绍了该光子晶体光纤在不同的椭圆率、椭圆归一化面积、微型双孔孔径、两小孔之间间距的情况下双折射和限制损耗随波长的变化曲线.模拟结果表明,通过同时在包层和纤芯引入非对称性,获得了较高的双折射(～10-3量级)和极低(～10-4 dB/km)的限制损耗.提供了一种新的光子晶体光纤设计方法,即通过同时在包层和纤芯引入新结构来同时获得高双折射和低损耗.

A novel highly birefringent photonic crystal fiber（PCF） with elliptical air holes in the fiber cladding and arrays of subwavelength double-hole units with size of about 0.16 μm in the fiber core was proposed.Dispersion and birefringence property of the proposed PCFs was investigated by using a full-vector finite-element method（FEM） and anisotropic perfectly matched layers.Curves between modal birefringence（confinement loss） of the proposed PCFs and the wavelength of the input light for PCFs with different parameters of ellipticity,normalized area,diameter of the two microholes,distance between the two microholes are reported in details.Simulation results showed that high birefringence（larger than 0.001） and ultralow confinement loss（less than 0.000 2 dB/km） are achieved.The proposed design of the PCF is an approach to achieve both the high birefringence and the low confinement loss by introducing asymmetric microstructure both in the fiber cladding and in the fiber core.