Abstract We propose a solid-core Bragg few-mode fiber with alternating layers of high/low refractive indices. The refractive index of the low-index layer in the cladding is the same as that of the fiber core. The influences of filling ratio, periodic structure width and core size on n eff , Δ n eff and A eff are investigated. Bending loss of each guided mode and differential mode delay (DMD) between adjacent spatial modes are also studied at 1550 nm. With appropriate geometrical parameters, the minimum effective refractive index difference (min Δ n eff ) between adjacent modes is 2 × 10−3 at 1550 nm. Wavelength-dependent performance is analyzed subsequently ranging from 1180 nm to 1630 nm. Numerical simulations indicate that such fiber could support 7 linearly polarized (LP) modes and have good bending insensibility performance. These results illustrate that the proposed fiber could be a promising candidate for mode division multiplexing to enhance optical transmission capacity.

中文翻译：

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O+C+L波段短距离MDM网络实芯布拉格少模光纤设计

摘要 我们提出了一种具有高/低折射率交替层的实芯布拉格少模光纤。包层中低折射率层的折射率与纤芯的折射率相同。研究了填充率、周期结构宽度和纤芯尺寸对n eff 、Δ n eff 和A eff 的影响。还在 1550 nm 处研究了每个导模的弯曲损耗和相邻空间模式之间的差模延迟 (DMD)。在适当的几何参数下，相邻模式之间的最小有效折射率差 (min Δ n eff ) 在 1550 nm 处为 2 × 10-3。随后分析了波长相关的性能，范围从 1180 nm 到 1630 nm。数值模拟表明，这种光纤可以支持7种线偏振（LP）模式，并具有良好的弯曲不敏感性能。