C6v对称六角与圆形空气柱TIR-PCF基模色散比较

摘要

设计了一种由六角形空气柱包层组成的C6v (六重旋转对称)全内反射型 PCF(光子晶体光纤)，采用全矢量有限元法研究其基模色散，数值研究结果表明，在其他参数不变的情况下，包层空气柱由圆形变成六角形后两基模偏振态会出现分离现象，存在较大的模式双折射与较高的PMD(偏振模色散)，基模的波长色散在X偏振时与包层圆形空气柱时有相同的变化曲线，说明包层空气柱形状对基模色散特性有较大影响。%A C6v TIR-PCF (the six-fold rotation symmetry total internal reflection photonic crystal fiber)of cladding with hexa-gonal air column is designed in this paper.The fundamental mode dispersion characteristics are investigated numerically by full vector finite element method.The numerical results show that when other parameters are unchanged,original two fundamental mode polarization are separated if the shape of the cladding air column changes from circular to hexagonal.We can also observe a large mode birefringence and high degree of polarization mode dispersion.The results also show that the wavelength disper-sion of the fundamental mode in X polarization have the same variation curve with cladding circular air column.It means that the fundamental mode dispersion characteristic has a great influence on the shape of cladding air column.