Incorporating an Optical Clock into a Time Scale at NIST: Simulations and Preliminary Real-Data Analysis

Jeffrey Sherman, Tara Fortier, Jian Yao, Thomas Parker, Judah Levine, Joshua Savory, Stefania Romisch, William McGrew, Xiaogang Zhang, Daniele Nicolodi, Robert Fasano, Stephan Schaeffer, Kyle Beloy, and Andrew Ludlow

Abstract:	This paper describes the recent NIST work on incorporating an optical clock into a time scale. We simulate a time scale composed of continuously-operating commercial hydrogen masers and an optical frequency standard that does not operate continuously as a clock. The simulations indicate that to achieve the same performance of a continuously-operating Cs-fountain time scale, it is necessary to run an optical frequency standard 12 min per half a day, or 1 hour per day, or 4 hours per 2.33 day, or 12 hours per week. Following the simulations, a Yb optical clock at NIST was frequently operated during the periods of 2017 March – April and 2017 late October – late December. During this operation, comb-mediated measurements between the Yb clock and a hydrogen maser had durations ranging from a few minutes to a few hours, depending on the experimental arrangements. This paper analyzes these real data preliminarily, and discusses the results. More data are needed to make a more complete assessment.
Published in:	Proceedings of the 49th Annual Precise Time and Time Interval Systems and Applications Meeting January 29 - 1, 2018 Hyatt Regency Reston Reston, Virginia
Pages:	11 - 21
Cite this article:	Sherman, Jeffrey, Fortier, Tara, Yao, Jian, Parker, Thomas, Levine, Judah, Savory, Joshua, Romisch, Stefania, McGrew, William, Zhang, Xiaogang, Nicolodi, Daniele, Fasano, Robert, Schaeffer, Stephan, Beloy, Kyle, Ludlow, Andrew, "Incorporating an Optical Clock into a Time Scale at NIST: Simulations and Preliminary Real-Data Analysis," Proceedings of the 49th Annual Precise Time and Time Interval Systems and Applications Meeting, Reston, Virginia, January 2018, pp. 11-21. https://doi.org/10.33012/2018.15624
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