Demonstration of a Timescale Based on a Stable Optical Carrier

Author
Abstract
We report on the first timescale based entirely on optical technology. Existing timescales, including those incorporating optical frequency standards, rely exclusively on microwave local oscillators owing to the lack of an optical oscillator with the required frequency predictability and stability for reliable steering. We combine a cryogenic silicon cavity exhibiting improved long-term stability and an accurate <sup>87</sup>Sr lattice clock to form a timescale that outperforms them all. Our timescale accumulates an estimated time error of only 48±94 ps over 34 days of operation. Our analysis indicates that this timescale is capable of reaching a stability below 1 x 10<sup>-17</sup> after a few months of averaging, making timekeeping at the 10<sup>-18</sup> level a realistic prospect.
Year of Publication
2019
Journal
Physical Review Letters
Volume
123
Date Published
2019-10
ISSN Number
0031-9007
URL
https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.123.173201
DOI
10.1103/PhysRevLett.123.173201
JILA PI
Associated Institutes
Journal Article