提出了一种具有中心缺陷孔的新型非对称椭圆光子晶体光纤，采用全矢量有限元法研究了其双折射、色散和非线性等特性。通过改变第一层椭圆孔的角度，加强了结构的双折射性能，同时还能改善结构的色散表现。分析计算结果得出，设计合适的结构参数可在波长1.55 μm处获得3.05×10-2的高双折射，同时在X和Y偏振方向获得较高非线性系数。此外，在保持高双折射的同时，此PCF也可获得1 000~1 550 nm近550 nm的负色散平坦区。该新型近红外波段的高双折射高非线性负平坦色散的光子晶体光纤在偏振控制、非线性光学及光纤通信等领域具有广泛的应用前景。

A novel type of asymmetric elliptical-hole photonic crystal fiber (PCF) with a central defect hole was proposed. The full vector finite element method was adopted to investigate its birefringence, dispersion and non-linear characteristics. By changing angle of the first layer of the elliptic hole, birefringence properties of the structure are strengthened, which also can improve the dispersion performance of the structure at the same time. The analysis results demonstrated that fibers with a value of 305×10-2 for birefringence at the wavelength of 1.55 μm can be obtained by setting suitable structure parameters, meanwhile with high nonlinear coefficients in both X and Y polarization directions. Furthermore, while maintaining the high birefringence, the proposed PCF also has negative flat dispersion of nearly 550 nm from 1 000 nm to 1 550 nm. The photonic crystal fiber with the new structure has wide applications for the polarization control, nonlinear optics and optical fiber communication.