Two-way coherent frequency transfer in a commercial DWDM communication network in Sweden
Paper in proceeding, 2015

An experimental fiber link is being established between SP Technical Research Institute of Sweden in Boras and Chalmers University of Gothenburg in Sweden. The one way fiber length is about 60 km and implemented in SUNET (Swedish University Network). The aim of the project is to evaluate the signal quality when sending a stable optical frequency utilizing a wavelength in a DWDM (Dense Wavelength Division Multiplexing) system fiber pair. The experiment uses a channel in the DWDM with the wavelength of 1542.14 nm. This wavelength is within the C band and is therefore compatible with common Erbium doped amplifiers in this network. Another aim of the system is to be ultra-stable which corresponds to a stability of 1×10-13 for τ = 1 s as well as providing the ability to distribute monitored ultra-stable frequency with a future traceability to UTC (SP) (National realization of Universal Time Coordinated within Sweden) to multiple users within the network. Measurements of an optical frequency transfer using a fiber-link based on unidirectional light signals in parallel fibers have shown promising results in a free-running setup and in a lab environment. The fractional frequency stability, analyzed as the Overlapping Allan deviation, is approximately 3×10-13 at τ = 10 s and almost 1×10-14 at 105 s.

Optical fiber network

Frequency transfer


Optical fiber


Sven-Christian Ebenhag

SP Sveriges Tekniska Forskningsinstitut AB

M. Zelan

SP Sveriges Tekniska Forskningsinstitut AB

Per Olof E Hedekvist

SP Sveriges Tekniska Forskningsinstitut AB

Magnus Karlsson

Chalmers, Microtechnology and Nanoscience (MC2), Photonics

B. Josefsson

Swedish University Computer Network

2015 Joint Conference of the IEEE International Frequency Control Symposium and the European Frequency and Time Forum, FCS 2015 - Proceedings

1075-6787 (ISSN)

978-147998866-2 (ISBN)

Subject Categories

Atom and Molecular Physics and Optics





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