在空心布拉格光纤拉制过程中引入的光纤外径波动会造成不同位置光纤包层一维光子晶体结构的光子带隙不完全重叠，极大地影响光纤的传输特性。研究了外径慢变正弦波动下，空心布拉格光纤中各类模式的传输特性。理论计算表明，尽管各模式类传输特性不尽相同，同一类模式中，不同阶的模式损耗情况也不一样，但是，各模式的外径波动容限相差不大。在计算例中，TE0n模的外径波动容限大约为9％，TM0n，HE和EH模式的外径波动容限在6％～7％。采用的理论分析方法可以拓展到其他光纤结构参数组合和任意光纤波动情况。

During the fabrication process of hollow-core Bragg fibers, outer diameter variations would be induced unavoidably, which lead to band gap shifts of the one dimensional photonic crystal structures in the fiber claddings, impacting their transmission characteristics severely. The mode transmission characteristics of hollow-core Bragg fibers with slowly sine variation in outer diameter have been investigated. The simulation results show that, despite the transmission characteristics are different between different mode classes and the mode losses are different between modes in the same mode class with different orders, the diameter variation tolerances are almost the same. In the case calculated, the diameter variation tolerances of the TE0n mode are about 9%, and 6%～7% for the TM0n, HE and EH modes. The method deployed can be used for any diameter variations and structure parameters.