Abstract The cylindrical vector beams (CVBs) as the spatially orthogonal modes in fiber provide additional degree of freedom for optical fiber communication. The ring-core fibers with a high refractive index area matching with the beam shape of CVBs are suitable for stable transmission of CVBs. We simulate and experimentally characterize the CVBs transmission in ring-core fibers with different geometric structure parameters. We demonstrated the transmission of CVBs from 2nd to 7th orders with mode purities higher than 80% and demonstrate the multiplexing communication of coaxial high order CVBs in ring-core fiber. The model we build to calculate the largest CVB mode number and order supported in the ring-core fiber are consistent with the experimental results of our three ring-core fibers. From the simulation results, the higher order CVB modes show larger effective refractive index differences and less crosstalk compared with the lower orders modes. According to the calculation, it is possible to transmit up to 4 mode groups of high order CVB modes in the ring-core fiber with optimized geometric parameters, given by the effective refractive index threshold of 2 × 10−3.

中文翻译：

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用于高阶柱面矢量光束模式传输的环芯光纤几何结构优化

摘要 作为光纤中空间正交模式的圆柱矢量光束（CVB）为光纤通信提供了额外的自由度。具有与CVBs光束形状匹配的高折射率区域的环芯光纤适用于CVBs的稳定传输。我们模拟并实验表征了具有不同几何结构参数的环芯光纤中的 CVBs 传输。我们演示了模式纯度高于 80% 的 2 阶到 7 阶 CVB 的传输，并演示了环芯光纤中同轴高阶 CVB 的复用通信。我们建立的用于计算环芯光纤中支持的最大 CVB 模式数和阶数的模型与我们的三种环芯光纤的实验结果一致。从模拟结果来看，与低阶模式相比，高阶 CVB 模式显示出更大的有效折射率差异和更少的串扰。根据计算，可以在具有优化几何参数的环芯光纤中传输多达 4 个模式组的高阶 CVB 模式，有效折射率阈值为 2 × 10-3。