提出了一种新型的微结构纤芯的光子晶体光纤，在纤芯中引入10个呈矩形排列的小圆空气孔，包层空气孔呈阶梯渐增结构。采用全矢量有限元法，通过改变纤芯小圆空气孔的大小和二者之间的孔间距，研究了这种光纤的基模模场、双折射、限制损耗和色散特性。研究结果表明，当小圆半径r1=0.225 μm，孔间距Λ2=1.30 μm时，在波长1.55 μm处，双折射为3.22×10-2，限制损耗低至4.92×10-8 dB/m，且在0.6~2.0 μm之间可获得三个零色散点。另外，通过优化纤芯结构参数，在波长1.55 μm处，双折射最大值可达3.45×10-2,损耗最低达2.88×10-9 dB/m。该设计为在光纤通信、光纤传感方面的应用提供了理论基础。

A new kind of micro-structured core photonic crystal fiber with a rectangular array of ten air holes in the core region and the incremental cladding is proposed. Using the finite element method, the fundamental mode field, birefringence, confinement loss and dispersion characteristics are investigated simultaneously by changing the radii and pitches of the air holes in the core. Numerical results show that the birefringence and confinement loss are respectively about 3.22×10-2 and 4.92×10-8 dB/m at 1.55 μm when the small air hole radius is 0.225 μm and the cladding air hole pitch size is 1.30 μm, and three corresponding zero dispersion points can be obtained over the wavelength range from 0.6 μm to 2.0 μm. In addition, the largest birefringence can reach up to 3.45×10-2 and the confinement loss reduces down to 2.88×10-9 dB/m by optimizing the structural parameters. The proposed photonic crystal fiber has a broad prospect of applications in fiber-optic communications, fiber optic sensing and other fields.