Effect of soil temperature on optical frequency transfer through unidirectional dense-wavelength-division-multiplexing fiber-optic links.

T J Pinkert,F C Bosveld,O Böll,L Willmann,R Smets,W Ubachs,K Jungmann,K S E Eikema,J C J Koelemeij,B G H M Groeneveld,E A Dijck,G S M Jansen

doi:10.1364/ao.54.000728

T J Pinkert, F C Bosveld + Show 10 more

Open Access

https://doi.org/10.1364/ao.54.000728

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Abstract

Results of optical frequency transfer over a carrier-grade dense-wavelength-division-multiplexing (DWDM) optical fiber network are presented. The relation between soil temperature changes on a buried optical fiber and frequency changes of an optical carrier through the fiber is modeled. Soil temperatures, measured at various depths by the Royal Netherlands Meteorology Institute (KNMI) are compared with observed frequency variations through this model. A comparison of a nine-day record of optical frequency measurements through the 2×298 km fiber link with soil temperature data shows qualitative agreement. A soil temperature model is used to predict the link stability over longer periods (days-months-years). We show that optical frequency dissemination is sufficiently stable to distribute and compare, e.g., rubidium frequency standards over standard DWDM optical fiber networks using unidirectional fibers.

Highlights

In recent years, fiber-optic connections in telecommunication networks have proven to be suitable for frequency comparisons and frequency distribution with high stability over long distances
The optical path between VU University Amsterdam and Van Swinderen Institute Groningen is marked in green
We investigated the passive frequency stability of a 2 × 298 km carrier-grade, unidirectional fiber link between VU University Amsterdam LaserLaB and Van Swinderen Institute, University of Groningen, using a single DWDM channel, and with live optical data traffic present in other DWDM channels

Summary

Introduction

Fiber-optic connections in telecommunication networks have proven to be suitable for frequency comparisons and frequency distribution with high stability over long distances. Fiber-optic methods for remote frequency comparison can provide significantly better stability than current satellite-based methods. Plans for high-resolution laser spectroscopy experiments at VU University Amsterdam LaserLaB and at Van Swinderen Institute, University of Groningen, would be greatly facilitated by direct frequency comparisons over an optical fiber link at stability levels better than 10−14 at

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