Seafloor geophysical instrumentation is challenging to deploy and maintain but critical for
studying submarine earthquakes and Earth's interior. Emerging fiber-optic sensing …

Ultrastable lasers are essential tools in optical frequency metrology enabling unprecedented
measurement precision that impacts on fields such as atomic timekeeping, tests of …

Quantum mechanics allows distribution of intrinsically secure encryption keys by optical
means. Twin-field quantum key distribution is one of the most promising techniques for its …

This paper outlines the roadmap towards the redefinition of the second, which was recently
updated by the CCTF Task Force created by the CCTF in 2020. The main achievements of …

Observation of polarization modulation at the output of a submarine link, extracted from a
standard coherent telecom receiver, can be used to monitor geophysical events such as sea …

Among the most powerful techniques for the exploration of the Universe is very long
baseline interferometry (VLBI), which is based on the simultaneous observation of radio …

The comparison of distant atomic clocks is foundational to international timekeeping, global
positioning and tests of fundamental physics. Optical-fibre links allow the most precise …

We introduce multi-branch repeater laser stations (MLSs) for the dissemination of an ultra-
stable signal from one point to multiple users and the simultaneous evaluation of the stability …

Submarine optical cables, utilized as fiber-optic sensors for seismic monitoring, are gaining
increasing interest because of their advantages of extending the detection coverage …

The large-scale clock network is the key ingredient to obtain high precision in many
scenarios, from fundamental research to cutting-edge applications. The advantage of the …