English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

We report on the characterization, including residual phase noise and fractional frequency instability, of fiber-coupled periodically poled Lithium Niobate non-linear crystals. These components are devoted to frequency doubling 871-nm light from an extended-cavity diode laser to produce a 435.5-nm beam, corresponding to the ytterbium ion electric quadrupole clock transition. We measure the doubling efficiencies of up to 117.5%/W. Using a Mach-Zehnder interferometer and an original noise rejection technique, the residual phase noise of the doublers is estimated to be lower than -35 dBrad<sup>2</sup>/Hz at 1 Hz, making these modules compatible with up-to-date optical clocks and ultra-stable cavities. The influence of external parameters, such as pump laser frequency and intensity, is investigated, showing that they do not limit the stability of the frequency-doubled signal. Our results demonstrate that such compact, fiber-coupled modules are suitable for use in ultra-low phase noise metrological experiments, including transportable optical atomic clocks.

Residual Phase Noise Measurement of Optical Second Harmonic Generation in PPLN Waveguides