The Belgian Optical network for Optical frequency Standards and TimE Dissemination (BOOSTED) project, launched in 2023 thanks to an INFRA funding from BELSPO, aims to make accessible, in a secured way, the signals generated by the atomic clocks operated at the Royal Observatory of Belgium.

Compared to common techniques such as NTP (~1ms in accuracy), PTP (~1µs) or GNSS (~30 ns), the new Time service dedicated to the time dissemination aims to reach an accuracy of 1ns. These achievements, made possible by the White Rabbit (WR) technology initially developed at CERN, are relying on optical links. Therefore, they are insensitive to GNSS threats (like jamming, spoofing, ...), supporting the development of resilient infrastructure.

The Frequency service operates in a completely different way. A transferred analog signal, supported by a nearly pure sine wave, is obtained through the phase stabilisation of an optical carrier. The laser light is located in the middle of the channel C44 of the ITU 100GHz-grid, corresponding to a frequency 194.4 THz, or a wavelength of 1542.14nm. This technique, already widely use in France within the REFIMEVE infrastructure, is so accurate, with a stability transfer of the link better than 10^-20, that the only limitation is coming from the atomic source itself. Overcoming by far the GNSS capabilities, this approach is the only one able to deliver the full performances of the last generation of atomic clocks, working no more in the microwave domain, but now in the optical domain.

This project would not be possible without the valuable collaboration of our partner BELNET who is actively working to adapt its network to enable secure transfer of the T&F signals.

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