title: Phase-coherent frequency comparison of optical clocks using a telecommunication fiber link.
abstract: We have explored the performance of 2 "dark fibers" of a commercial telecommunication fiber link for a remote comparison of optical clocks. These fibers establish a network in Germany that will eventually link optical frequency standards at PTB with those at the Institute of Quantum Optics (IQ) at the Leibniz University of Hanover, and the Max Planck Institutes in Erlangen (MPL) and Garching (MPQ). We demonstrate for the first time that within several minutes a phase coherent comparison of clock lasers at the few 10(-15) level can also be accomplished when the lasers are more than 100 km apart. Based on the performance of the fiber link to the IQ, we estimate the expected stability for the link from PTB to MPQ via MPL that bridges a distance of approximately 900 km.
authors.affiliation: Physikalisch-Technische Bundesanstalt, Braunschweig, Germany. herald.schnatz@ptb.de
authors.forename: Harald
authors.initials: H
authors.lastname: Schnatz
authors.forename: Osama
authors.initials: O
authors.lastname: Terra
authors.forename: Katharina
authors.initials: K
authors.lastname: Predehl
authors.forename: Thorsten
authors.initials: T
authors.lastname: Feldmann
authors.forename: Thomas
authors.initials: T
authors.lastname: Legero
authors.forename: Burghard
authors.initials: B
authors.lastname: Lipphardt
authors.forename: Uwe
authors.initials: U
authors.lastname: Sterr
authors.forename: Gesine
authors.initials: G
authors.lastname: Grosche
authors.forename: Ronald
authors.initials: R
authors.lastname: Holzwarth
authors.forename: Theodor W
authors.initials: TW
authors.lastname: Hänsch
authors.forename: Thomas
authors.initials: T
authors.lastname: Udem
authors.forename: Zehuang H
authors.initials: ZH
authors.lastname: Lu
authors.forename: Li J
authors.initials: LJ
authors.lastname: Wang
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Ertmer
authors.forename: Jan
authors.initials: J
authors.lastname: Friebe
authors.forename: Andrè
authors.initials: A
authors.lastname: Pape
authors.forename: Ernst-M
authors.initials: EM
authors.lastname: Rasel
authors.forename: Mathias
authors.initials: M
authors.lastname: Riedmann
authors.forename: Temmo
authors.initials: T
authors.lastname: Wübbena
mesh_terms: D017076:Computer-Aided Design; D004867:Equipment Design; D019544:Equipment Failure Analysis; D008872:Microwaves; D055100:Optical Fibers; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013685:Telecommunications / Q000295:instrumentation*; D013997:Time Factors