Two-way time transfer via optical fiber providing subpicosecond precision and high temperature stability

Kodet, Jan; Panek, Petr; Procházka, Ivan

doi:10.1088/0026-1394/53/1/18

Cited by 58 publications

(20 citation statements)

References 22 publications

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“…We note that researchers are also trying to adopt the component used in our quantum scheme to improve the time stability of the terminals. For example, as ETs (e.g., A033-ET from Eventech Ltd. has a 3.5-5 ps single-shot time resolution) can have better timing resolution than the time-interval counters (e.g., the best product SR620 from Stanford Research Systems has a 25 ps single-shot time resolution), they have been applied to TWTTOF as the timing signal receiver, and a TDEV better than 60 fs for averaging intervals from 100 s to 10 000 s was achieved after being calibrated for its temperature dependence to 100 fs/K [46]. For the timeof-arrival detection, single photon counting approach allows to reduce the systematic biases as much as possible, and is therefore adopted in the applications of Satellite Laser Ranging (SLR) and Time Transfer by Laser Link (T2L2).…”

Section: Appendix B: Comparison Of Q-twttof and Twttofmentioning

confidence: 99%

Fiber-optic two-way quantum time transfer with frequency-entangled pulses

et al. 2019

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High-precision time transfer is of fundamental interest in physics and metrology. Quantum time transfer technologies that use frequency-entangled pulses and their coincidence detection have been proposed, offering potential enhancements in precision and better guarantees of security. In this paper, we describe a fiber-optic two-way quantum time transfer experiment. Using quantum nonlocal dispersion cancellation, time transfer over a 20-km fiber link achieves a time deviation of 922 fs over 5 s and 45 fs over 40960 s. The time transfer accuracy as a function of fiber lengths from 15 m to 20 km is also investigated, and an uncertainty of 2.46 ps in standard deviation is observed. In comparison with its classical counterparts, the fiber-optic two-way quantum time transfer setup shows appreciable improvement, and further enhancements could be obtained by using new event timers with sub-picosecond precision and single-photon detectors with lower timing jitter for optimized coincidence detection. Combined with its security advantages, the femtosecond-scale two-way quantum time transfer is expected to have numerous applications in high-precision middle-haul synchronization systems.

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Section: Appendix B: Comparison Of Q-twttof and Twttofmentioning

confidence: 99%

Fiber-optic two-way quantum time transfer with frequency-entangled pulses

et al. 2019

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“…where ∆a, ∆e are given by Eqs. (54) and (50), respectively. This term is about 5.8×10 2 m. Since LISA requires that the difference in length of the two arms is known to 200m [23], TianQin has the similar requirement for the arm length.…”

Section: The Frequency Shift Between High Earth-orbiting Satellitesmentioning

confidence: 99%

Relativistic tidal effects on clock-comparison experiments

Qin

Tan

Shao

2019

Class. Quantum Grav.

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We consider the relativistic tidal effects on frequency shift of clockcomparison experiments. The relativistic formulation for frequency shift and time transfer is derived in the gravitational field of a tidal, axisymmetric, and rotating Earth. With the help of Love numbers describing the tidal response of solid Earth, we formulize the mathematical connection between tidal effects from the ground-based clock-comparison experiments and the local gravity tides from the gravimeters, which in turn provides us an approach to eliminate tidal influences on clock comparison with the local gravity tides data. Moreover, we develop a method of the perturbed Kepler orbit to determine relativistic effects of clock comparison for space missions, which allows more precise calculations comparing to the conventional method of unperturbed Kepler orbit. With this perturbed method, it can give the perturbation of relativistic effects due to the orbital changes under the influences of tidal forces, Earth's oblateness etc. In addition, as the applications of our results, we simulate tidal effects in frequency shift for the clock comparison on the ground and also give some estimates for TianQin mission and GPS.

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“…Furthermore it is possible to establish the long-term stability of time and frequency distribution system as well as the SLR systems on the observatory. In order to demonstrate the resolution and stability of the novel time and frequency distribution system, we have compared two independent links in different buildings more than 50 m apart with each other, using an asynchronous two-way time comparison system (Kodet et al 2015). Figure 7 depicts the results.…”

Section: Delay Extraction By the Virtue Of Closure Measurementsmentioning

confidence: 99%

The Application of Coherent Local Time for Optical Time Transfer and the Quantification of Systematic Errors in Satellite Laser Ranging

Kodet

2017

Space Sci Rev

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Highly precise time and stable reference frequencies are fundamental requirements for space geodesy. Satellite laser ranging (SLR) is one of these techniques, which differs from all other applications like Very Long Baseline Interferometry (VLBI), Global Navigation Satellite Systems (GNSS) and finally Doppler Orbitography and Radiopositioning Integrated by Satellite (DORIS) by the fact that it is an optical two-way measurement technique. That means that there is no need for a clock synchronization process between both ends of the distance covered by the measurement technique. Under the assumption of isotropy for the speed of light, SLR establishes the only practical realization of the Einstein Synchronization process so far. Therefore it is a powerful time transfer technique. However, in order to transfer time between two remote clocks, it is also necessary to tightly control all possible signal delays in the ranging process. This paper discusses the role of time and frequency in SLR as well as the error sources before it address the transfer of time between ground and space. The need of an improved signal delay control led to a major redesign of the local time and frequency distribution at the Geodetic Observatory Wettzell. Closure measurements can now be used to identify and remove systematic errors in SLR measurements.

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Two-way time transfer via optical fiber providing subpicosecond precision and high temperature stability

Cited by 58 publications

References 22 publications

Fiber-optic two-way quantum time transfer with frequency-entangled pulses

Fiber-optic two-way quantum time transfer with frequency-entangled pulses

Relativistic tidal effects on clock-comparison experiments

The Application of Coherent Local Time for Optical Time Transfer and the Quantification of Systematic Errors in Satellite Laser Ranging

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