BOOSTED stands for 'Belgium Optical network for Optical frequency Standards and TimE Dissemination' and aims to develop an optical network for time & frequency (T&F) transfer in Belgium and connect it, via France, to the European metrological network.
BOOSTED in a nutshell
BOOSTED is funded by INFRA-FED, an initiative of the federal government to promote the development of emerging research infrastructures within federal research institutions. The project - led by the Royal Observatory of Belgium (ROB) - started at the end of April 2023 and will run until the end of 2026. The project is currently in the exploration phase and the technical requirements to be met to transport the ultra-stable time & frequency signal over the Belnet fibre optic network are being explored. To this end, there is close consultation between the ROB, Belnet, UCLouvain, REFIMEVE, the Observatoire de Paris and the Laboratoire de Physique des Lasers (LPL, Paris).
The rationale behind time & frequency transfer via fibre optics
The ROB maintains a time and frequency laboratory, whose atomic clocks contribute to the international reference UTC (Coordinated Universal Time). Moreover, they also generate an accurate realization of UTC, a basis for Belgian legal time, namely UTC (ORB), which is available to Belgian users. Today, time and frequency transfer occurs using global navigation satellite systems (such as the American GPS system and the European Galileo system), with an uncertainty of 10-15 in relative frequency over a one-day average. The advantage of GNSS technology is that it is available everywhere and at a reasonable cost. However, this transfer is prone to interference and is unsuitable for applications requiring higher precision, e.g. precision spectroscopy and photonic research.
A promising alternative is T&F distribution over optical fibre, which can outperform GNSS T&F transfer by several orders of magnitude. Various European time laboratories are already connected and the process of distributing their realisation of UTC (Coordinated Universal Time) to scientific institutions and to industry via fibre optics has already begun.
The role of Belnet
Belnet is formally participating in BOOSTED as a subcontractor, but brings a lot of expertise in the field of network and time & frequency transfer. Following France's example, the ROB aims to use the national research network linking universities and research centres. It therefore turned to Belnet, operator of the Belgian research network, to enable metrological signal and data traffic to be transported in parallel over its fibre optic network, without interference. In Belgium, a connection will be designed between the Royal Observatory of Belgium and several Belgian universities, where the ultra-stable frequency will be used for high-resolution laser spectroscopy (e.g. UCLouvain) and for photonic research (ULB, or UGent). Belnet network engineers are currently working out various schematic set-ups for transporting this ultra-stable T&F signal over the Belnet backbone. Belnet will also be responsible for connecting to the French network REFIMEVE, through which an ultra-stable reference frequency is already distributed.