Validating frequency transfer via interferometric fiber links for optical clock comparisons

authored by: Sebastian Koke, Erik Benkler, Alexander Kuhl, Gesine Grosche
Abstract: We investigate the validation of fiber-based optical frequency transfer for frequency comparison applications. We specifically consider the frequency transfer validation for remote optical clock comparisons and want to ensure interferometric fiber link uncertainty contributions below the combined uncertainty of the clocks under test. The validation is based on signals obtained via looping back from the remote end to the sender site and comparing the input with the output of the loop. These loop-back data need to be averaged over intervals for reaching the validation goal, as the short-term instability of long-distance interferometric fiber links is typically higher than that of optical clocks. We introduce a two-step validation approach and address the finding of a compromise between opposing aspects of averaging: reaching low uncertainties versus achieving a high data coverage of the validated data set via a high temporal resolution of the fault identification. We discuss the impact of different averaging types and of the tolerance of filtering criteria on the achievable estimated uncertainty and on the coverage of the validated data set. Data from four multiple-week-long measurement campaigns on the fiber link between Physikalisch-Technische Bundesansanstalt and University of Strasbourg are used for this assessment.
Organisation(s): QuantumFrontiers
CRC 1464: Relativistic and Quantum-Based Geodesy (TerraQ)
External Organisation(s): National Metrology Institute of Germany (PTB)
Type: Article
Journal: New journal of physics
Volume: 23
ISSN: 1367-2630
Publication date: 20.09.2021
Publication status: Published
Peer reviewed: Yes
ASJC Scopus subject areas: Physics and Astronomy(all)
Electronic version(s): https://doi.org/10.1088/1367-2630/ac21a0 (Access: Open)

BibTeX

@article{4d76929bd3b847e7b2b1d273df186387,
title = "Validating frequency transfer via interferometric fiber links for optical clock comparisons",
abstract = "We investigate the validation of fiber-based optical frequency transfer for frequency comparison applications. We specifically consider the frequency transfer validation for remote optical clock comparisons and want to ensure interferometric fiber link uncertainty contributions below the combined uncertainty of the clocks under test. The validation is based on signals obtained via looping back from the remote end to the sender site and comparing the input with the output of the loop. These loop-back data need to be averaged over intervals for reaching the validation goal, as the short-term instability of long-distance interferometric fiber links is typically higher than that of optical clocks. We introduce a two-step validation approach and address the finding of a compromise between opposing aspects of averaging: reaching low uncertainties versus achieving a high data coverage of the validated data set via a high temporal resolution of the fault identification. We discuss the impact of different averaging types and of the tolerance of filtering criteria on the achievable estimated uncertainty and on the coverage of the validated data set. Data from four multiple-week-long measurement campaigns on the fiber link between Physikalisch-Technische Bundesansanstalt and University of Strasbourg are used for this assessment.",
keywords = "optical clock comparisons, optical clocks, optical fiber links, optical frequency dissemination, ultra-stable lasers",
author = "Sebastian Koke and Erik Benkler and Alexander Kuhl and Gesine Grosche",
note = "Publisher Copyright: {\textcopyright} 2021 The Author(s). Published by IOP Publishing Ltd on behalf of the Institute of Physics and Deutsche Physikalische Gesellschaft.",
year = "2021",
month = sep,
day = "20",
doi = "10.1088/1367-2630/ac21a0",
language = "English",
volume = "23",
journal = "New journal of physics",
issn = "1367-2630",
publisher = "IOP Publishing Ltd.",
number = "9",
}