We propose a new method to achieve single-polarization guidance in a hollow-core negative-curvature fiber. Simulation results show that coating a layer of high-index material with a suitable thickness on the inner surface of one vertical cladding tube in a hollow-core negative-curvature fiber can effectively suppress $y$ -polarized fundamental mode. Silicon is chosen as the high-index material in this paper. In the five-nested-tube silicon-coated negative-curvature fiber, the single-polarization region is located in the wavelength range of 1512–1587 nm with a broad bandwidth of 75 nm. The polarization extinction ratio is up to 1732 at the wavelength of 1550 nm. Moreover, the mode evolutions of $x$ - and $y$ -polarized fundamental modes in the five-nested-tube silicon-coated negative-curvature fiber are investigated to explain why $y$ -polarized fundamental mode is suppressed. Compared with the traditional method of using different tube thicknesses to achieve single-polarization guidance in a negative-curvature fiber, this method possesses the advantages of broad single-polarization bandwidth and high error tolerance.

中文翻译：

---

一种在空心负曲率光纤中实现单极化制导的新方法

我们提出了一种在空芯负曲率光纤中实现单极化引导的新方法。仿真结果表明，在空芯负曲率光纤的一根垂直包层管内表面涂覆一层合适厚度的高折射率材料可以有效抑制 $y$ -极化基模。本文选择硅作为高折射率材料。在五嵌套管涂硅负曲率光纤中，单偏振区位于 1512-1587 nm 的波长范围内，带宽为 75 nm。在1550nm波长处偏振消光比高达1732。此外，模式的演变 $x$ - 和 $y$ - 研究了五嵌套管涂硅负曲率光纤中的偏振基模以解释原因 $y$ -极化基模被抑制。与传统的在负曲率光纤中采用不同管厚实现单极化引导的方法相比，该方法具有单极化带宽宽、容错率高等优点。