Phase noise of frequency doublers in optical clock lasers

authored by: Sofia Herbers, Sören Dörscher, Erik Benkler, Christian Lisdat
Abstract: Frequency doublers are widely used in high-resolution spectroscopy to shift the operation wavelength of a laser to a more easily accessible or otherwise preferable spectral region. We investigate the use of a periodically-poled lithium niobate (PPLN) waveguide frequency doubler in an optical clock. We focus on the phase evolution between the fundamental (1396 nm) and frequency-doubled (698 nm) light and its effect on clock performance. We find that the excess phase noise of the doubler under steady-state operation is at least two orders of magnitude lower than the noise of today’s best interrogation lasers. Phase chirps related to changes of the optical power in the doubler unit and their influence on the accuracy of optical clocks are evaluated. We also observe substantial additional noise when characterizing the doubler unit with an optical frequency comb instead of using two identical waveguide doublers.
External Organisation(s): National Metrology Institute of Germany (PTB)
Type: Article
Journal: Optics express
Volume: 27
Pages: 23262-23273
No. of pages: 12
ISSN: 1094-4087
Publication date: 2019
Publication status: Published
Peer reviewed: Yes
ASJC Scopus subject areas: Atomic and Molecular Physics, and Optics
Electronic version(s): https://doi.org/10.1364/OE.27.023262 (Access: Open)

BibTeX

@article{de02141f77b04d808734a58421b49629,
title = "Phase noise of frequency doublers in optical clock lasers",
abstract = "Frequency doublers are widely used in high-resolution spectroscopy to shift the operation wavelength of a laser to a more easily accessible or otherwise preferable spectral region. We investigate the use of a periodically-poled lithium niobate (PPLN) waveguide frequency doubler in an optical clock. We focus on the phase evolution between the fundamental (1396 nm) and frequency-doubled (698 nm) light and its effect on clock performance. We find that the excess phase noise of the doubler under steady-state operation is at least two orders of magnitude lower than the noise of today{\textquoteright}s best interrogation lasers. Phase chirps related to changes of the optical power in the doubler unit and their influence on the accuracy of optical clocks are evaluated. We also observe substantial additional noise when characterizing the doubler unit with an optical frequency comb instead of using two identical waveguide doublers.",
author = "Sofia Herbers and S{\"o}ren D{\"o}rscher and Erik Benkler and Christian Lisdat",
note = "Funding information: Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) (CRC 1128 project A03, CRC 1227 project B02, EXC-2123/1); European Space Agency (ESA) (4000119716).",
year = "2019",
doi = "10.1364/OE.27.023262",
language = "English",
volume = "27",
pages = "23262--23273",
journal = "Optics express",
issn = "1094-4087",
publisher = "OSA - The Optical Society",
number = "16",
}