CNRS is France’s leading public research organisation and oversees three laboratories contributing to SENSEI:

• Laboratoire Temps-Espace (LTE) in Paris, a national reference in time and frequency metrology,
• Laboratoire de Physique des Lasers (LPL) near Paris, specialised in light–matter interactions, from quantum and atomic physics to biomedical optics and photonics,
• Laboratoire GéoAzur near Nice, a multidisciplinary lab combining geophysics, geology, astronomy and space geodesy to study Earth and planetary dynamics and marine environments.

LPL and LTE jointly operate REFIMEVE, a national infrastructure that distributes ultra-stable frequency and time signals through telecom optical fibers, over the RENATER network (French National Telecommunications Network for Technology, Education and Research).

Map of the REFIMEVE network.
Full line: operational links / Dashed line: future links / Green: REFIMEVE link / Blue: Italian, German and British links.

Three research laboratories actively engaged in SENSEI

At the core of SENSEI, LTE, LPL, and GéoAzur are developing new photonic solutions for distributed sensing over active telecom fibers. The project involves:

• Advancing fiber-optic technologies to enable sensing on live networks,
• Field deployment and testing of these innovations,
• Analysis and interpretation of sensing data from a geophysical perspective

The three CNRS laboratories are actively engaged in close collaboration with many SENSEI partners, reflecting our strong commitment to the cooperative spirit of the project.

Already routinely detecting seismic events along the French fiber network

Within REFIMEVE, seismic events are now routinely detected along the French fiber network. Recent internal catalogues have recorded over 200 earthquakes of magnitude Mw > 5 in just two years, demonstrating the potential of national infrastructure for seismic sensing.

Detection of an event happening in Mexico, seen by a seismometer by Paris and by a 43 km fiber link near Paris.

Turning telecom networks into large-scale distributed environmental sensors through advanced fiber stabilization

Through SENSEI, CNRS aims to foster close collaboration between research and telecom stakeholders to co-design effective solutions for geoscience applications and the future of time-frequency fiber networks. The project is a unique opportunity to align technological innovation with scientific needs and pave the way for sustainable, multifunctional optical fiber networks.

…more to come: stay tuned!