18SIB06 TiFOON: Advanced time/frequency comparison and dissemination trough optical telecommunication networks

• Forschungsstelle: METAS
• Projektnummer: F-5117.30123

Schlüsselwörter (Englisch)

Time and frequency dissemination, optical fibres, frequency comparison, time scales, optical clocks, frequency standards, redefinition of the SI second.

Kurzbeschreibung (Englisch)

The unprecedented accuracy of modern optical clocks has spurred the development of matching frequency comparison techniques, with optical frequency transfer over fibre emerging as the method of choice. However, international time scales, as well as applications outside metrology, require reliable and economically sustainable time transfer in addition to frequency transfer capabilities. This project will advance fibre-based frequency transfer capabilities in Europe towards a universal tool for time and frequency metrology and beyond.

This is a joint research project carried out in the framework of the European Metrology Programme for Innovation and Research (EMPIR) (see:http://www.euramet.org/research-innovation/empir/). The EMPIR initiative is co-funded by the European Unions's Horizon 2020 research and innovation programme and the participating states. METAS is one of the project partners in the project.

Projektziele (Englisch)

The overall objective of the project is to advance fibre-based frequency transfer capabilities in Europe towards a sustainable, universal tool for time and frequency metrology, matching the unprecedented accuracy of modern optical clocks.

The specific objectives of the project are:

1. To sustainably expand existing capabilities for optical fibre frequency transfer towards time transfer. Specifically, this means integrating optical carrier, radio frequency (rf) and time dissemination and comparison techniques with the aim of limiting spectrum usage to a single International Telecommunication Union (ITU) channel. The target accuracy for the combined service is 1 part in 1018 for frequency and 100 ps for time, simultaneously. In order to implement such techniques in existing fibre links between NMIs, it will also be necessary to investigate how to extend the compatibility of specialised amplification techniques with rf and time transfer. In addition, novel concepts of time transfer over fibre with the potential of reaching sub-ps accuracy will be explored.
2. To further enhance and develop optical fibre frequency transfer technology, with the aim of human intervention-free operation over several weeks. Also, to identify and address performance-limiting factors, with the aim of achieving 1 part in 1018 uncertainty within less than one hour for long-distance fibre links, thus matching the expected performance of improved optical clocks.
3. To investigate the compatibility of optical time and frequency transfer with simultaneous data traffic in a laboratory test environment or deployed fibre infrastructure, in order to determine conditions under which they operate mutually disruption-free. Compatibility tests will concentrate on commercial telecommunications equipment deployed in national research and education networks (NREN) and the pan-European network GÉANT.
4. To disseminate ultra-stable frequency and timing signals beyond the NMIs. Particular attention will be paid to identifying the benefits of disseminating time, as opposed to pure frequency. This includes demonstrating and facilitating novel applications in geodesy and earth observation. Specifically, essential functionalities for the proper transfer of time between widely spaced geodetic markers will be investigated.
5. To facilitate the take-up of the technology and measurement infrastructure developed in the project by the measurement supply chain (NMIs), standard developing organisations (e.g. ITU-T) and end users (NREN and other fibre network operators, earth science and geodesy communities, calibration laboratories).