
8 November 2022
The diffusion of signals from the latest generation of atomic clocks, operating at very high frequencies of nearly 400 THz, poses new challenges for their comparison over continental distances and beyond. The means of transferring these signals by optical fiber allows a real technological breakthrough, and finds applications in the fields of metrology, fundamental physics, navigation and spectroscopy. A challenge remains to operate these revolutionary means reliably over time while maintaining a very high level of performance.
The journal Physical Review Applied has just published an article from the French-Italian collaboration that addresses this challenge. This article shows the realization of a 1023 km long fiber optic link between the national metrology institutes in Italy and France, largely based on the national infrastructures, REFIMEVE in France and IQB in Italy. These infrastructures are sustainable because they rely on the mutualization of the fiber network operated for education and research. In France, it is RENATER that allows this access to its network. It is the first time that two large national networks are interconnected, allowing subsequently to connect all the users connected by these fiber networks.
But for these users to be able to rely on these new infrastructures, the service must be available in the long term. Here, the Franco-Italian team shows a record duration of quasi-continuous operation of 4 months, during which the collaboration compared the atomic clocks at Cs, Rb and Yb of the metrology institutes. This record duration of comparison between atomic clocks further underlines the potential of this new infrastructure to evaluate the uncertainty budgets of clocks, characterize advanced satellite techniques, and develop optical time scales.
This first integration of the fiber optic metrology infrastructures of the two countries, France and Italy, which also link more than twenty research laboratories and observatories of the IVS and IGS network, provides a new impetus to the European research community with a physical layer on which new research can be built.
More:
Read the research article: https://journals.aps.org/prapplied/abstract/10.1103/PhysRevApplied.18.054009
Visit refimeve web site
Visit IQB at Inrim:
Visit the webpages for the team Optical Frequency at SYRTE
Contact : Paul-Eric Pottie
paul-eric(dot)pottie(at)obspm.fr