提出了一种新型压缩六边形空气孔阵列的SPSM-PCF（单偏振单模光子晶体光纤）结构，并采用全矢量有限元方法以完美匹配层为边界条件研究了该光纤的限制损耗特性随结构参量变化的规律。数值模拟结果表明，在入射波长为1.550 μm时，快轴模的限制损耗很大，而慢轴模的限制损耗随包层层数的增加而减小，当包层层数Nr分别为6、8和10时，限制损耗分别为4.534×10-4、2.236×10-5和9.597×10-6 dB/m。因此，快轴模在极短的光纤长度内快速衰减，从而实现仅有慢轴模且限制损耗低于0.1 dB/km的低损耗单模单偏振运转。

A novel Single-Polarization Single-Mode Photonic Crystal Fiber (SPSM-PCF) with squeezed hexagonal air holes array is proposed and the regular pattern of its confinement loss characteristics changes with the structural parameters is investigated by using a full-vector Finite Element Method (FEM) with a Perfect Matched Layer (PML) as the boundary condition. Numerical simulation results indicate that the confinement loss of the fast-axis mode is large whereas that of the slow-axis mode decreases with the increase of the number of the air-hole rings Nr, e.g. they are 4.534×10-4,2.236×10-5, 9.597×10-6 dB/m at 1.550 μm when Nr=6,8,10 respectively. As the fast-axis mode is fast attenuated within a short length of fiber, a SPSM-PCF with the slow-axis mode only and the confinement loss less than 0.1 dB/km is obtained.