Frequency transfer through long-distance optical fibre links for relativistic geodesy (A04)

正如爱因斯坦的广义相对论所预言的那样，电磁辐射在通过引力场时会经历频率漂移，这就是所谓的引力性红移。正如Vermeer在1983年和BJerhammar在1985年提出的那样，测量时钟之间的表观频率差从而使我们能够确定偏远地点之间的潜在(或高度)差异。该项目的目标是通过光纤远距离传输光学频率，在不同位置的时钟之间实现“计时均衡”。这一努力可能会支持未来全球高度参考网格的统一。

As predicted by Einstein’s general theory of relativity, electromagnetic radiation experiences a frequency shift when travelling through a gravitational field, known as gravitational red shift. As proposed by Vermeer in 1983, and Bjerhammar in 1985, measuring this apparent frequency difference between clocks thus allows us to determine potential (or height) differences between remote sites. The goal of this project is to realise “chronometric levelling” by transferring optical frequencies via optical fibre over large distances, between clocks at different locations. This effort may support future unification of worldwide height reference grids.