High-resolution optical frequency dissemination on a telecommunication network with data traffic

TL;DR

This paper demonstrates the successful transfer of ultra-stable laser frequency over a 108 km urban fiber network carrying Internet data, achieving high stability and paving the way for remote optical clock dissemination.

Contribution

It introduces a method to transfer ultra-stable laser frequencies over existing telecommunication networks with data traffic using wavelength division multiplexing and phase noise cancellation.

Findings

Achieved an Allan deviation of a few 10^-16 at 1 second

Maintained stability below 10^-19 at 10,000 seconds

Successfully integrated metrological signals with data traffic in a real network

Abstract

We transferred the frequency of an ultra-stable laser over a 108 km urban fiber link comprising 22 km of optical communications network fiber simultaneously carrying Internet data traffic. The metrological signal and the digital data signal are transferred on two different frequency channels in a dense wavelength division multiplexing scheme. The metrological signal is inserted into and extracted from the communications network by using bidirectional off-the-shelf optical add-drop multiplexers. The link-induced phase noise is measured and cancelled with round-trip technique using an all-fiber-based interferometer. The compensated link shows an Allan deviation of a few 10-16 at one second and below 10-19 at 10,000 seconds. This opens the way to a wide dissemination of ultra stable optical clock signals between distant laboratories via the Internet network.