Opt Lett. 2020 Nov 1;45(21):6074-6077. doi: 10.1364/OL.404866.
High-quality frequency transfer based on existing telecommunication fiber links allows state-of-the-art microwave and optical clocks to be compared on a continental and potentially even intercontinental scale. We present a half-a-year-long data set of unidirectional optical frequency transfer over a 2×43 urban fiber link. We observe a relative frequency instability of 8.0×10 at 1 s and at best 6.0×10 at 10 integration time. Our results show that the unidirectional two-way method gives the possibility to perform comparisons of international primary standards over fiber links faster than over satellite links. Moreover, we investigate the major limiting factors of such a unidirectional setup.
基于现有电信光纤链路的高质量频率传递使得最先进的微波和光学时钟能够在大陆甚至洲际范围内进行比较。我们提出了一个长达半年的单向光频传递数据集，跨越了 2×43 公里的城市光纤链路。我们观察到在 1 秒时的相对频率不稳定度为 8.0×10 ，在 10 次积分时间时最佳为 6.0×10 。我们的结果表明，单向双向方法使得在光纤链路而不是卫星链路中进行国际基准的比较成为可能，速度比卫星链路更快。此外，我们还研究了这种单向设置的主要限制因素。
