There are a host of applications in communications, sensing, and science, in which analogue signal transmission is preferred over today’s dominant digital transmission. In some of these applications, the advantage is in lower cost, while in others, it lies in superior performance. However, especially for longer analogue photonics links (up to 10 s of km), the performance is strongly limited by the impairments arising from using standard single-mode fibres (SSMF). Firstly, the three key metrics of analogue links (loss, noise figure, and dynamic range) tend to improve with received power, but this is limited by stimulated Brillouin scattering in SSMF. Further degradation is due to the chromatic dispersion of SSMF, which induces radio-frequency (RF) signal fading, increases even-order distortions, and causes phase-to-intensity-noise conversion. Further distortions still, are caused by the Kerr nonlinearity of SSMF. We propose to address all of these shortcomings by replacing SSMFs with hollow-core optical fibres, which have simultaneously six times lower chromatic dispersion and several orders of magnitude lower nonlinearity (Brillouin, Kerr). We demonstrate the advantages in this application using a 7.7 km long hollow-core fibre sample, significantly surpassing the performance of an SSMF link in virtually every metric, including 15 dB higher link gain and 6 dB lower noise figure.

在通信、传感和科学领域有许多应用，其中模拟信号传输优于当今占主导地位的数字传输。在其中一些应用中，优势在于成本较低，而在其他应用中，优势在于卓越的性能。然而，特别是对于更长的模拟光子链路（高达 10 s km），性能受到使用标准单模光纤 (SSMF) 产生的损伤的强烈限制。首先，模拟链路的三个关键指标（损耗、噪声系数和动态范围）往往会随着接收功率而提高，但这受到 SSMF 中受激布里渊散射的限制。进一步的退化是由于 SSMF 的色散引起的，它会导致射频 (RF) 信号衰落，增加偶次失真，并导致相位到强度的噪声转换。进一步的失真仍然是由 SSMF 的克尔非线性引起的。我们建议通过用空芯光纤替换 SSMF 来解决所有这些缺点，空芯光纤同时具有低六倍的色散和低几个数量级的非线性（布里渊，克尔）。我们使用 7.7 公里长的空芯光纤样品展示了此应用中的优势，在几乎所有指标上都显着超过了 SSMF 链路的性能，包括链路增益提高 15 dB 和噪声系数降低 6 dB。