November 2019. Muquans’s engineers and the research teams at SYRTE and LPL deployed a 2x856-km coherent optical link between Paris and Grenoble and back. The link uses the fibres of National and Research Network (NREN) RENATER. The successfully stabilize the fluctuations of the propagation delay down to a few fs (1 fs = 10-15 s) for several hours. This is about 3 order of magnitude better than what can be achieved with a GPS signal.

This is a worl record on such a distance and an important step for REFIMEVE REFIMEVE+ as a large instrument. REFIMEVE REFIMEVE+ is a fiber for ultra-stable optical frequency dissemination over France with several interconnexion to European countries. This shows the technical readiness and the maturity of the REFIMEVE technique as well as our capacity to operate and supervise efficiently coherent optical link with the support of RENATER.