In 2024, a new Special Interest Group for the Time & Frequency Network (SIG-TFN), was established to provide a forum for the community working around Time & Frequency (T&F) distribution across NRENs. We spoke with Domenico Vicinanza, SIG-TFN coordinator, and Guy Roberts, the SIG-TFN technical working group leader and member of the Steering Committee, to discover more about SIG-TFN’s activities and key developments since its formation.
Can you describe the vision and goals that guide SIG-TFN’s efforts?
SIG-TFN aims to establish a forum for sharing experiences, ideas, and expertise regarding the development, deployment, testing, and standardisation of T&F distribution across R&E networks, with a particular emphasis on interoperability. The key stakeholders in SIG-TFN are the metrology scientists, European National Metrology Institutes (NMIs) and NRENs who together have partnered to build national T&F distribution networks in their respective countries. How does the SIG help foster collaboration and knowledge sharing within the community? The SIG organises regular group meetings, online and face-to-face, and uses online collaborative tools, collating and disseminating information, and organising pilot projects. The SIG-TFN steering committee aims to have two face-to-face meetings annually as we continue to build new international T&F links.
What are some key topics and trends that SIG-TFN has been focusing on?
European national T&F networks are now being interconnected at the European level via the new Core-Time Frequency Network (C-TFN). The SIG is currently dedicated to facilitating the development of the C-TFN, which will serve as the first pan-European infrastructure for distributing T&F within Europe. A technical working group within the SIG-TFN has been formed to bring together technical experts from the metrology and networking communities to specify the design requirements for the C-TFN.
Can you share some key outcomes from the SIG-TFN meetings?
One of the main outcomes of the SIG-TFN so far, has been the installation of the first T&F link between Braunschweig (PTB, Germany) and Poznań (PSNC, Poland), last September.
The link between the PTB and PSNC was installed on a pair of optical fibres provided by PIONIER/PSNC in Poland (~270 km) and leased by GÉANT in Germany (~420 km). In total, the link is 690 km long and has 10 ILAs – signal amplification points (2 x 10 amplifiers). Frequency distribution over this link has proven to be highly stable – sufficient to compare the latest generation of optical atomic clocks. In Q2 2025 a campaign has been operating on this link to compare German and Polish clocks.
What direction do you see SIG-TFN taking in the coming years?
We anticipate an even greater and more robust collaboration among users (researchers, international projects, and organisations relying on T&F), NRENs, and NMIs. It’s remarkable to see how rapidly the SIG has evolved into an international hub and a highly effective open forum, with nearly 100 members, from a dedicated group of 30 individuals who first gathered in Geneva just a year ago.
We hope the SIG-TFN will continue to be a forum where metrologists and research networks can agree a common vision for T&F in Europe and present this vision to the European Commission. As we build a stronger community, we hope to increase awareness of the need for a European T&F distribution network to ensure Europe’s strategic infrastructure sovereignty.
We are observing an exciting natural synergy with SIG-Quantum, a new SIG within the GÉANT community. We aim to collaborate and may even co-host some of our meetings, as quantum technologies and T&F distributions share a common foundation at the physical layer.
For further details, visit www.community.geant.org/sig-tfn
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