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Génération de signaux micro-ondes pour la métrologie à partir de références et de peignes de fréquences optiques

Abstract : In this Ph. D. thesis a system developed to generate a microwave signal with high frequency stability is presented. Such an ultra low noise signal is produced by phase locking an Erbium doped fiber femtosecond laser comb to an ultra-stable optical reference. The frequency stability of the optical source is thus transferred to the microwave domain. In first step several ultra-stables lasers have been developed to be used as optical reference by frequency locking a laser to a high finesse Fabry-Perot cavity. Vibrations sensitivity of the optical cavity has been strongly reduced by the carefully choice of the cavity geometry using finite element modeling and experimental adjustment. The comparison of two ultra-stables lasers show a fractional frequency stability of about 5.8×10^(-16) @ 1 s using fused silica cavity mirror substrates. One of these lasers together with the femtosecond laser comb has been used to generate a microwave signal at ~12 GHz with a fractional stability of 3×10^(-15) at 1 s. This spectrally pure signal is used for the interrogation of cesium atomic fountain clock which achieves his fundamental limit with a stability of 3.5×10^(-14)τ^(-1/2). It is shown that the frequency noise of the interrogation signal is negligible in the frequency stability budget of the clock. Finally, the noise of the optical to microwave division process has been evaluated using two identical femtosecond laser combs stabilized on a common stable optical reference. After optimization, this limitation is measured at the level of 2-3×10^(-16) for integration time between 1 s and 10 s.
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https://tel.archives-ouvertes.fr/tel-00637969
Contributor : Jacques Millo <>
Submitted on : Thursday, November 3, 2011 - 1:56:09 PM
Last modification on : Thursday, April 2, 2020 - 1:28:26 PM
Document(s) archivé(s) le : Saturday, February 4, 2012 - 2:25:35 AM

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  • HAL Id : tel-00637969, version 1

Citation

Jacques Millo. Génération de signaux micro-ondes pour la métrologie à partir de références et de peignes de fréquences optiques. Physique Atomique [physics.atom-ph]. Université Pierre et Marie Curie - Paris VI, 2010. Français. ⟨tel-00637969⟩

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