He, YabaiOrr, Brian JWouters, Michael JLuiten, Andre NAben, GuidoWarrington, Richard BBaldwin, Kenneth2016-05-112016-05-1112/08/20131094-4087http://hdl.handle.net/1885/101204We demonstrate long-distance (≥100-km) synchronization of the phase of a radio-frequency reference over an optical-fiber network without needing to actively stabilize the optical path length. Frequency mixing is used to achieve passive phase-conjugate cancellation of fiber-length fluctuations, ensuring that the phase difference between the reference and synchronized oscillators is independent of the link length. The fractional radio-frequency-transfer stability through a 100-km "real-world" urban optical-fiber network is 6 × 10(-17) with an averaging time of 10(4) s. Our compensation technique is robust, providing long-term stability superior to that of a hydrogen maser. By combining our technique with the short-term stability provided by a remote, high-quality quartz oscillator, this system is potentially applicable to transcontinental optical-fiber time and frequency dissemination where the optical round-trip propagation time is significant.This work has received support from the Australian Research Council through its Linkage Project funding scheme (project number LP110100270) and a Future Fellowship (project number FT0991631) awarded to one of us (A. L.).1 vol.application/pdfen-AU2013 Optical Society of Americahttps://creativecommons.org/licenses/by/4.0/Keywords: Compensation techniques; Long term stability; Optical path lengths; Optical-fiber networks; Radio frequencies; Short term stability; Synchronized oscillator; Time and frequency disseminations; Mixing; Optical fibers; Quartz; Fibers201310.1364/OE.21.0187542016-06-14Attribution 4.0 International (CC BY 4.0)