Frequency Comparison of 171 +Ion Optical Clocks at PTB and NPL via GPS PPP

J. Leute, N. Huntemann, B. Lipphardt, Christian Tamm, P. B.R. Nisbet-Jones, S. A. King, R. M. Godun, J. M. Jones, H. S. Margolis, P. B. Whibberley, A. Wallin, M. Merimaa, P. Gill, E. Peik

Research output: Contribution to journalArticleScientificpeer-review

11 Citations (Scopus)

Abstract

We used precise point positioning, a well-established GPS carrier-phase frequency transfer method to perform a direct remote comparison of two optical frequency standards based on single laser-cooled 171 + ions operated at the National Physical Laboratory (NPL), U.K. and the Physikalisch-Technische Bundesanstalt (PTB), Germany. At both institutes, an active hydrogen maser serves as a flywheel oscillator which is connected to a GPS receiver as an external frequency reference and compared simultaneously to a realization of the unperturbed frequency of the 2S1/2}(F=0)-2D-3/2(F=2) electric quadrupole transition in 171 + via an optical femtosecond frequency comb. To profit from long coherent GPS-link measurements, we extrapolate the fractional frequency difference over the various data gaps in the optical clock to maser comparisons which introduces maser noise to the frequency comparison but improves the uncertainty from the GPS-link instability. We determined the total statistical uncertainty consisting of the GPS-link uncertainty and the extrapolation uncertainties for several extrapolation schemes. Using the extrapolation scheme with the smallest combined uncertainty, we find a fractional frequency difference y(PTB)-y(NPL) of -1.3× 10-15 with a combined uncertainty of 1.2× 10-15 for a total measurement time of 67 h. This result is consistent with an agreement of the frequencies realized by both optical clocks and with recent absolute frequency measurements against caesium fountain clocks within the corresponding uncertainties.

Original languageEnglish
Article number7398135
Pages (from-to)981-985
Number of pages5
JournalIEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
Volume63
Issue number7
DOIs
Publication statusPublished - 1 Jul 2016
MoE publication typeA1 Journal article-refereed

Fingerprint

clocks
Global positioning system
Clocks
Ions
Extrapolation
ions
extrapolation
masers
Hydrogen masers
Spurious signal noise
Masers
Fountains
Frequency standards
hydrogen masers
Flywheels
flywheels
Cesium
frequency standards
Uncertainty
Time measurement

Keywords

  • Frequency transfer
  • GPS precise point positioning (PPP)
  • optical clock

Cite this

Leute, J., Huntemann, N., Lipphardt, B., Tamm, C., Nisbet-Jones, P. B. R., King, S. A., ... Peik, E. (2016). Frequency Comparison of 171 +Ion Optical Clocks at PTB and NPL via GPS PPP. IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control, 63(7), 981-985. [7398135]. https://doi.org/10.1109/TUFFC.2016.2524988
Leute, J. ; Huntemann, N. ; Lipphardt, B. ; Tamm, Christian ; Nisbet-Jones, P. B.R. ; King, S. A. ; Godun, R. M. ; Jones, J. M. ; Margolis, H. S. ; Whibberley, P. B. ; Wallin, A. ; Merimaa, M. ; Gill, P. ; Peik, E. / Frequency Comparison of 171 +Ion Optical Clocks at PTB and NPL via GPS PPP. In: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control. 2016 ; Vol. 63, No. 7. pp. 981-985.
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title = "Frequency Comparison of 171 +Ion Optical Clocks at PTB and NPL via GPS PPP",
abstract = "We used precise point positioning, a well-established GPS carrier-phase frequency transfer method to perform a direct remote comparison of two optical frequency standards based on single laser-cooled 171 + ions operated at the National Physical Laboratory (NPL), U.K. and the Physikalisch-Technische Bundesanstalt (PTB), Germany. At both institutes, an active hydrogen maser serves as a flywheel oscillator which is connected to a GPS receiver as an external frequency reference and compared simultaneously to a realization of the unperturbed frequency of the 2S1/2}(F=0)-2D-3/2(F=2) electric quadrupole transition in 171 + via an optical femtosecond frequency comb. To profit from long coherent GPS-link measurements, we extrapolate the fractional frequency difference over the various data gaps in the optical clock to maser comparisons which introduces maser noise to the frequency comparison but improves the uncertainty from the GPS-link instability. We determined the total statistical uncertainty consisting of the GPS-link uncertainty and the extrapolation uncertainties for several extrapolation schemes. Using the extrapolation scheme with the smallest combined uncertainty, we find a fractional frequency difference y(PTB)-y(NPL) of -1.3× 10-15 with a combined uncertainty of 1.2× 10-15 for a total measurement time of 67 h. This result is consistent with an agreement of the frequencies realized by both optical clocks and with recent absolute frequency measurements against caesium fountain clocks within the corresponding uncertainties.",
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Leute, J, Huntemann, N, Lipphardt, B, Tamm, C, Nisbet-Jones, PBR, King, SA, Godun, RM, Jones, JM, Margolis, HS, Whibberley, PB, Wallin, A, Merimaa, M, Gill, P & Peik, E 2016, 'Frequency Comparison of 171 +Ion Optical Clocks at PTB and NPL via GPS PPP', IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control, vol. 63, no. 7, 7398135, pp. 981-985. https://doi.org/10.1109/TUFFC.2016.2524988

Frequency Comparison of 171 +Ion Optical Clocks at PTB and NPL via GPS PPP. / Leute, J.; Huntemann, N.; Lipphardt, B.; Tamm, Christian; Nisbet-Jones, P. B.R.; King, S. A.; Godun, R. M.; Jones, J. M.; Margolis, H. S.; Whibberley, P. B.; Wallin, A.; Merimaa, M.; Gill, P.; Peik, E.

In: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control, Vol. 63, No. 7, 7398135, 01.07.2016, p. 981-985.

Research output: Contribution to journalArticleScientificpeer-review

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T1 - Frequency Comparison of 171 +Ion Optical Clocks at PTB and NPL via GPS PPP

AU - Leute, J.

AU - Huntemann, N.

AU - Lipphardt, B.

AU - Tamm, Christian

AU - Nisbet-Jones, P. B.R.

AU - King, S. A.

AU - Godun, R. M.

AU - Jones, J. M.

AU - Margolis, H. S.

AU - Whibberley, P. B.

AU - Wallin, A.

AU - Merimaa, M.

AU - Gill, P.

AU - Peik, E.

N1 - CA2: BA1173 CA2: BA117 Project code: 104545 AU2: Wallin, Anders AU2: Merimaa, Mikko ISI: ACOUSTICS

PY - 2016/7/1

Y1 - 2016/7/1

N2 - We used precise point positioning, a well-established GPS carrier-phase frequency transfer method to perform a direct remote comparison of two optical frequency standards based on single laser-cooled 171 + ions operated at the National Physical Laboratory (NPL), U.K. and the Physikalisch-Technische Bundesanstalt (PTB), Germany. At both institutes, an active hydrogen maser serves as a flywheel oscillator which is connected to a GPS receiver as an external frequency reference and compared simultaneously to a realization of the unperturbed frequency of the 2S1/2}(F=0)-2D-3/2(F=2) electric quadrupole transition in 171 + via an optical femtosecond frequency comb. To profit from long coherent GPS-link measurements, we extrapolate the fractional frequency difference over the various data gaps in the optical clock to maser comparisons which introduces maser noise to the frequency comparison but improves the uncertainty from the GPS-link instability. We determined the total statistical uncertainty consisting of the GPS-link uncertainty and the extrapolation uncertainties for several extrapolation schemes. Using the extrapolation scheme with the smallest combined uncertainty, we find a fractional frequency difference y(PTB)-y(NPL) of -1.3× 10-15 with a combined uncertainty of 1.2× 10-15 for a total measurement time of 67 h. This result is consistent with an agreement of the frequencies realized by both optical clocks and with recent absolute frequency measurements against caesium fountain clocks within the corresponding uncertainties.

AB - We used precise point positioning, a well-established GPS carrier-phase frequency transfer method to perform a direct remote comparison of two optical frequency standards based on single laser-cooled 171 + ions operated at the National Physical Laboratory (NPL), U.K. and the Physikalisch-Technische Bundesanstalt (PTB), Germany. At both institutes, an active hydrogen maser serves as a flywheel oscillator which is connected to a GPS receiver as an external frequency reference and compared simultaneously to a realization of the unperturbed frequency of the 2S1/2}(F=0)-2D-3/2(F=2) electric quadrupole transition in 171 + via an optical femtosecond frequency comb. To profit from long coherent GPS-link measurements, we extrapolate the fractional frequency difference over the various data gaps in the optical clock to maser comparisons which introduces maser noise to the frequency comparison but improves the uncertainty from the GPS-link instability. We determined the total statistical uncertainty consisting of the GPS-link uncertainty and the extrapolation uncertainties for several extrapolation schemes. Using the extrapolation scheme with the smallest combined uncertainty, we find a fractional frequency difference y(PTB)-y(NPL) of -1.3× 10-15 with a combined uncertainty of 1.2× 10-15 for a total measurement time of 67 h. This result is consistent with an agreement of the frequencies realized by both optical clocks and with recent absolute frequency measurements against caesium fountain clocks within the corresponding uncertainties.

KW - Frequency transfer

KW - GPS precise point positioning (PPP)

KW - optical clock

U2 - 10.1109/TUFFC.2016.2524988

DO - 10.1109/TUFFC.2016.2524988

M3 - Article

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VL - 63

SP - 981

EP - 985

JO - IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control

JF - IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control

SN - 0885-3010

IS - 7

M1 - 7398135

ER -