Hollow-core fibers (HCFs) are a potentially transformative fiber technology, where light is confined within a hollow core surrounded by a cladding composed of air holes defined by glass membranes. Dramatic reductions in the minimum losses achieved in a HCF are driving forward their application in low-latency data transmission and ultra-high-power delivery, and maximizing their performance is of increasing interest. Here, we demonstrate that introducing an extremely small gas-induced differential refractive index (GDRI) between the gas within the core and cladding regions of a HCF enables dramatic changes to a HCF’s optical properties, including loss, bend loss, and modality. Within this work, we focus on a tubular HCF and demonstrate through experiment and simulations that the confinement loss of this fiber can be reduced by a factor of 5 using a differential pressure of only 6.7 bar. Understanding GDRI is critical for applications where the gas content within the fiber is actively controlled. Moreover, GDRI provides a new means to control the optical properties of a HCF post-fabrication, opening up new areas of design space and providing a tool to tailor and enhance the optical performance of even state-of-the-art HCFs.

中文翻译：

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空芯光纤中气体诱导的微分折射率增强导引

空心光纤 (HCF) 是一种潜在的变革性光纤技术，其中光被限制在空心内，空心被包层包围，包层由玻璃膜限定的气孔组成。在 HCF 中实现的最小损耗的显着降低正在推动它们在低延迟数据传输和超高功率传输中的应用，并且最大化它们的性能越来越受到关注。在这里，我们证明了在 HCF 的纤芯和包层区域内的气体之间引入极小的气体诱导微分折射率 (GDRI) 可以显着改变 HCF 的光学特性，包括损耗、弯曲损耗和模态。在这项工作中，我们专注于管状 HCF，并通过实验和模拟证明，使用仅 6.7 bar 的压差，这种纤维的约束损失可以减少 5 倍。了解 GDRI 对于主动控制纤维内气体含量的应用至关重要。此外，GDRI 提供了一种控制 HCF 后加工光学特性的新方法，开辟了新的设计空间领域，并提供了一种工具来定制和增强即使是最先进的 HCF 的光学性能。