Long-distance frequency dissemination with a resolution of 10-17
  We use a new technique to disseminate microwave reference signals along ordinary optical fiber. The fractional frequency resolution of a link of 86 km in length is 10-17 for a one day integration time, a resolution higher than the stability of the best microwave or optical clocks. We use the link to compare the microwave reference and a CO2/OsO4 frequency standard that stabilizes a femtosecond laser frequency comb. This demonstrates a resolution of 3.10-14 at 1 s. An upper value of the instability introduced by the femtosecond laser-based synthesizer is estimated as 1.10-14 at 1 s. 
Christophe Daussy (LPL), Olivier Lopez (LPL), Anne Amy-Klein (LPL),   Andr\'ei N. Goncharov (LPL), Mickael Guinet (LPL), Chr...