Combining fiber Brillouin amplification with a repeater laser station for fiber-based optical frequency dissemination over 1400 km

• Published in: New journal of physics Vol. 21; no. 12; pp. 123017 - 123027
• Main Authors: Koke, Sebastian, Kuhl, Alexander, Waterholter, Thomas, Raupach, Sebastian M F, Lopez, Olivier, Cantin, Etienne, Quintin, Nicolas, Amy-Klein, Anne, Pottie, Paul-Eric, Grosche, Gesine
• Format: Journal Article
• Language: English
• Published: Bristol IOP Publishing 01.12.2019; Institute of Physics: Open Access Journals
• Subjects: Fiber lasers; frequency transfer; Instrumentation and Detectors; Long fibers; optical atomic clocks; optical fiber link; Optical frequency; Physics
• ISSN: 1367-2630; 1367-2630
• DOI: 10.1088/1367-2630/ab5d95

We investigate optical frequency dissemination over a 1400 km long fiber link in looped configuration over a pair of underground fibers between Braunschweig and Strasbourg. This fiber link is the first to combine fiber Brillouin amplifiers with a repeater laser station. Phase-coherent operation over more than five days is demonstrated. We analyze the repeatability of the performance over four campaigns and present results of 65 d in total. The weighted mean of the fractional frequency offset of the transferred optical frequency over the complete data set is (−1.1 0.4)×10-20. By analyzing the stabilization signals of the two individual fibers, the correlation of the phase noise on the two fibers is shown to be >98%.