Abgrall, M; Chupin, B; Uhrich, P; Lorini, L; Le Targat, R; Pointard, B; Lodewuck, J; Tunesi, J; Tran, D B A; Parsons, A O; Tofful, A; Robertson, B I; Johnson, M Y H; Feng, C-H; Schioppo, M; Curtis, E A; Hill, I R; Godun, R M; Margolis, H S (2024) Optically steered time scale generation at OP and NPL and remote comparisons. Journal of Physics: Conference Series, 2889. 012024

Preview

Text eid10125.pdf - Published Version Available under License Creative Commons Attribution. Download (1MB) | Preview

Abstract

In this paper, we present real-time optically steered time scales generated simultaneously at the Observatoire de Paris (OP) and the National Physical Laboratory (NPL). Throughout one month, experimental UTCx(k) time scales were generated concurrently in the two laboratories alongside the local operational UTC(k) time scales. The UTCx(k) time scales were based on hydrogen masers whose frequencies were calibrated by local optical frequency standards using optical frequency combs, with algorithms being developed for outlier filtering and frequency steering estimations in the two laboratories. The performance of the experimental time scales was assessed through local comparisons against the corresponding UTC(k) time scales, and also through remote comparisons performed both via Coordinated Universal Time (UTC) and by using the Global Positioning System (GPS) Precise Point Positioning (PPP) technique. The two optically steered time scales remained within 4 ns of each other, outperforming the corresponding UTC(k) over the same period. To our knowledge, this is the first reported comparison of two independent “optical time scale” prototypes, and the results demonstrate the capability of optical clocks to produce operational time scales.

Item Type:	Article
Keywords:	optical clocks, time scales
Subjects:	Time and Frequency > Optical Frequency Standards and Metrology
Divisions:	Time & Frequency
Identification number/DOI:	10.1088/1742-6596/2889/1/012024
Last Modified:	04 Mar 2025 14:56
URI:	https://eprintspublications.npl.co.uk/id/eprint/10125