Ultra-low noise microwave generation with fiber-based optical frequency comb and application to atomic fountain clock

J. Millo; M. Abgrall; M. Lours; E. M. L. English; H. Jiang; J. Guena; A. Clairon; S. Bize; Y. Le Coq; G. Santarelli; M. E. Tobar

doi:10.1063/1.3112574

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arXiv · 0901.3654

Ultra-low noise microwave generation with fiber-based optical frequency comb and application to atomic fountain clock

J. Millo·M. Abgrall·M. Lours·E. M. L. English·H. Jiang·J. Guena·A. Clairon·S. Bize·Y. Le Coq·G. Santarelli·M. E. Tobar

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Abstract

We demonstrate the use of a fiber-based femtosecond laser locked onto an ultra-stable optical cavity to generate a low-noise microwave reference signal. Comparison with both a liquid Helium cryogenic sapphire oscillator (CSO) and a Ti:Sapphire-based optical frequency comb system exhibit a stability about $3\times10^{-15}$ between 1 s and 10 s. The microwave signal from the fiber system is used to perform Ramsey spectroscopy in a state-of-the-art Cesium fountain clock. The resulting clock system is compared to the CSO and exhibits a stability of $3.5\times10^{-14}τ^{-1/2}$. Our continuously operated fiber-based system therefore demonstrates its potential to replace the CSO for atomic clocks with high stability in both the optical and microwave domain, most particularly for operational primary frequency standards.

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J. Millo, M. Abgrall, M. Lours, E. M. L. English, H. Jiang, J. Guena, A. Clairon, S. Bize, Y. Le Coq, G. Santarelli, M. E. Tobar. 2009-01-23. Ultra-low noise microwave generation with fiber-based optical frequency comb and application to atomic fountain clock. https://doi.org/10.1063/1.3112574

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