The distribution and the comparison of an ultrastable reference frequency using optical fibres have been greatly improved in the last ten years. LNE-SYRTE and LPL (University Paris 13) have been pioneering the development of these new methods. In this paper we present a review of the methods and the results obtained. The frequency stability and accuracy of optical links surpass the well-established methods using GNSS and geostationary satellites. In this paper we show that it is possible to use public telecommunication network carrying Internet data to compare and distribute ultrastable metrological signals over long distances. In addition both frequency stability and accuracy are equivalent to those obtained with links developed with a dedicated fibre network. This novel technique paves the way to the deployment of a national and continental wide ultrastable metrological optical network.

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