Optical frequency transfer - a European network

Short Name: OFTEN, Project Number: 15SIB05
Large fiber optical cables

Building a European optical fibre network for comparing optical atomic clocks.


Caesium atomic clocks are used to accurately define the second, the SI base unit of time. But optical atomic clocks are more accurate and more stable than caesium clocks, and are the most promising candidates for use in the proposed re-definition of the second. Clocks in different locations need to be regularly compared to reveal and reduce uncertainty, but the current satellite-based techniques used to compare caesium clocks are not precise enough. This project has built on the achievements of EMRP project SIB02 NEAT-FT and helped to unlock the full accuracy potential of optical atomic clocks, by developing comparison techniques for optical clocks based on optical fibres, including installing and upgrading fibre optic links between European National Measurement Institutes. This network will allow optical clocks to be compared at new levels of accuracy and will pave the way for future improvements in the precision of time measurement in fields such as transport, communications and finance. 

Project website
Publications
Two-Branch Fiber Link for International Clock Networks
2019

IEEE Transactions on Instrumentation and Measurement

Atomic clocks for geodesy
2018

Reports on Progress in Physics

Long haul time and frequency distribution in different DWDM systems
2018

IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control

Fiber optic time transfer between PTB and Deutsche Telekom using multi-link redundant topology
2017

2017 Joint Conference of the European Frequency and Time Forum and IEEE International Frequency Control Symposium (EFTF/IFC)

CLONETS – Clock network services strategy and innovation for clock services over optical-fibre networks
2017

2017 Joint Conference of the European Frequency and Time Forum and IEEE International Frequency Control Symposium (EFTF/IFC)

Frequency comb-assisted QCL stabilization for high resolution molecular spectroscopy
2017

2017 Joint Conference of the European Frequency and Time Forum and IEEE International Frequency Control Symposium (EFTF/IFCS)

Hybrid optical link for ultra-stable frequency comparison
2017

2017 Joint Conference of the European Frequency and Time Forum and IEEE International Frequency Control Symposium (EFTF/IFC)

Progress on the REFIMEVE+ project for optical frequency standard dissemination
2017

2017 Joint Conference of the European Frequency and Time Forum and IEEE International Frequency Control Symposium (EFTF/IFC)

Time and frequency transfer in modern DWDM telecommunication networks
2017

2017 Joint Conference of the European Frequency and Time Forum and IEEE International Frequency Control Symposium (EFTF/IFC)

Other Participants
Akademia Gorniczo-Hutnicza im. Stanislawa Staszica w Krakowie (Poland)
Centre National de la Recherche Scientifique (France)
Chalmers tekniska hoegskola AB (Sweden)
Instytut Chemii Bioorganicznej, Polskiej Akademii Nauk (Poland)