To significantly improve the frequency references used in radio-astronomy and the precision measurements in atomic physics, we provide frequency dissemination through a 642-km coherent optical fiber link. On the frequency transfer, we obtained a frequency instability of 3×10 −19 at 1,000 s in terms of Allan deviation on a 5-mHz measurement bandwidth, and an accuracy of 5×10 −19. The ultimate link performance has been evaluated by doubling the link to 1,284 km, demonstrating a new characterization technique based on the double round trip on a single fiber. This method is an alternative to previously demonstrated techniques for link characterization. In particular, the use of a single fiber may be beneficial to long hauls realizations in view of a continental fiber network for frequency and time metrology, as it avoids the doubling of the amplifiers, with a subsequent reduction in costs and maintenance. A detailed analysis of the results is presented, regarding the phase noise, the cycle-slips detection and removal and the instability evaluation. The observed noise power spectrum is seldom found in the literature; hence, the expression of the Allan deviation is theoretically derived and the results confirm the expectations.
High-accuracy coherent optical frequency transfer over a doubled 642-km fiber link / D. Calonico; C. Calosso; C. Clivati; G. A. Costanzo; A. Godone; M. Frittelli; A. Mura; N. Poli; D. V. Sutyrin; G. M. Tino; M. Zucco; F. Levi. - In: APPLIED PHYSICS. B, LASERS AND OPTICS. - ISSN 0946-2171. - ELETTRONICO. - (2014), pp. 979-986.
|Titolo:||High-accuracy coherent optical frequency transfer over a doubled 642-km fiber link|
|Data di pubblicazione:||2014|
|Digital Object Identifier (DOI):||http://dx.doi.org/10.1007/s00340-014-5917-8|
|Appare nelle tipologie:||1.1 Articolo in rivista|