We demonstrate in-line extraction of an ultrastable frequency signal over an optical link of 92 km of installed telecommunication fibers, following the proposition of Grosche in 2010 [German patent application DE 10.2008.062.139]. We show that the residual frequency noise at the extraction end is noticeably below that at the main link output when the extraction is near the input end, as expected from a simple model of the noise compensation. We obtain relative frequency instabilities, expressed as overlapping Allan deviation, of at 1 s averaging time and a few at one day. These results are state-of-the-art for a link using urban telecommunication fibers. We also propose an improved scheme, which delivers an ultrastable signal of higher power, in order to feed a secondary link. In-line extraction opens the way to a broad distribution of an ultrastable frequency reference, enabling a wide range of applications beyond metrology.
© 2014 Optical Society of AmericaFull Article | PDF Article
N. R. Newbury, P. A. Williams, and W. C. Swann
Opt. Lett. 32(21) 3056-3058 (2007)
H. Jiang, F. Kéfélian, S. Crane, O. Lopez, M. Lours, J. Millo, D. Holleville, P. Lemonde, Ch. Chardonnet, A. Amy-Klein, and G. Santarelli
J. Opt. Soc. Am. B 25(12) 2029-2035 (2008)
Fabien Kéfélian, Olivier Lopez, Haifeng Jiang, Christian Chardonnet, Anne Amy-Klein, and Giorgio Santarelli
Opt. Lett. 34(10) 1573-1575 (2009)