设计了一种基于四孔单元的光子晶体光纤, 它可以满足光通信系统中高双折射率、负色散和低限制损耗的要求,比起通常的三角结构光纤有着更高的双折射率, 并且结构制作也较简单。采用全矢量有限元法和各项异性完美匹配层法对所设计的光纤进行了仿真研究。仿真结果表明: 该光纤在1.55μm波长处可获得10-2数量级的双折射率, 在较宽广的波段范围具有大的负色散, 限制损耗低于10-9dB/m；该光纤在保偏光纤、单极化单模光纤、色散补偿光纤等方面具有重要的应用。

A novel photonic crystal fiber (PCF) based on a four-hole unit is proposed in order to meet the requirements of high birefringence, negative dispersion and confinement loss in fiber-optic communication. Compared with the triangle structure fiber, it has higher birefringence and simpler structure. The proposed design has been simulated based on the full vector finite element method (FVFEM) and anisotropic perfectly matched layers (APML). Analysis results show that the proposed PCF can achieve a high birefringence to the order of 10-2 at the wavelength of 1.55μm, a large negative dispersion over a wide wavelength range and confinement losses lower than 10-9dB/m simultaneously, which has important applications in polarization maintaining (PM) fibers, single polarization single mode (SPSM) fibers, dispersion compensation fibers and so on.