11 research outputs found
Understanding and exploiting metrological fiber networks for Sagnac sensing, frequency dissemination and geosensing
Les horloges atomiques sont les outils modernes de la mesure du temps. Depuis la redĂ©finition de la seconde en 1967 fondĂ©e sur l'interrogation d'une transition atomique du CĂ©sium 133, les horloges atomiques se sont considĂ©rablement amĂ©liorĂ©es. Cela a conduit Ă de nombreuses avancĂ©es technologiques au cours des 55 derniĂšres annĂ©es, dont beaucoup nĂ©cessitent un transfert prĂ©cis des signaux de temps et de frĂ©quence, un exemple important Ă©tant le systĂšme de positionnement global (GPS). Avec les rĂ©cents progrĂšs des horloges atomiques de derniĂšre gĂ©nĂ©ration, dites optique, les moyens traditionnels de diffusion des signaux d'horloge(s) ne sont plus adaptĂ©s si on n'accepte pas de ne pas dĂ©grader leurs performances. La mise en Ćuvre d'une nouvelle technologie a Ă©tĂ© dĂ©veloppĂ©e Ă cette fin dans plusieurs pays du monde ces derniĂšres annĂ©es. Elle utilise les fibres optiques comme support pour transfĂ©rer et comparer les signaux des rĂ©fĂ©rences de frĂ©quence atomique. Dans cette thĂšse, j'aborderai la mise en Ćuvre d'un rĂ©seau de fibres optiques en France. Je discuterai des processus gĂ©nĂ©raux de bruit de ces liaisons par fibre optique, et de leurs limites techniques et fondamentales. Des Ă©tudes approfondies de plusieurs applications d'un rĂ©seau de fibres sont prĂ©sentĂ©es. Celles-ci incluent l'Ă©valuation de la contribution de l'incertitude du rĂ©seau français de fibres optiques Ă la comparaison des horloges optiques. Ensuite, je prĂ©senterai une Ă©tudes sur l'utilisation de rĂ©seaux de fibres pour la dĂ©tection de phĂ©nomĂšnes gĂ©ophysiques. Cela inclut la dĂ©tection de l'effet Sagnac dans un lien Ă fibre dĂ©ployĂ© dans une topologie en anneau autour de Paris. Ensuite, je montrerai une Ă©tude de la dĂ©tection des tremblements de terre avec le rĂ©seau de fibres français, et je discuterai des perspectives d'utilisation d'une telle technologie.Atomic clocks are the modern tools of timekeeping. Ever since the redefinition of the second in 1967 based on an atomic transition of Cesium 133, the atomic clocks have improved drastically. This has lead to many technological advancements the last 55 years, many of which require precise transfer of time and frequency signals, a prominent example being the Global Positioning System (GPS). With the recent advancements of the last generation of state-of-the-art atomic clocks, so called optical clocks, traditional means of disseminating their signals without degrading their performance are no longer adequate. The implementation of a new technology for such purposes has in recent years been implemented in several countries around the world, which utilizes optical fibers as a medium to transfer and compare the signals of the atomic frequency references.In this thesis, I discuss the exploitation of such an optical fiber network in France. I discuss the general noise processes of such fiber links, and their technical and fundamental limits. In-depth studies of several applications of a fiber network is presented. These include the evaluation of the uncertainty contribution of the French fiber network to the comparison of optical clocks. I also show studies of the use of fiber networks for the sensing of effects arising from the Earth. This includes the sensing of the Sagnac effect in a fiber link deployed in a ring topology around Paris, a study of the detection of earthquakes with the French fiber network, and a discussion of the prospects of the use of such a technology
ReÌseaux de liens fibreÌs en meÌtrologie pour la dissemination de freÌquence : etude, exploitation, et sensibiliteÌs aÌ l'effet Sagnac et autres perturbations terrestres
Atomic clocks are the modern tools of timekeeping. Ever since the rede nition of the second in 1967 based on an atomic transition of Cesium 133, the atomic clocks have improved drastically. This has lead to many technological advancements the last 55 years, many of which require precise transfer of time and frequency signals, a prominent example being the Global Positioning System (GPS). With the recent advancements of the last generation of state-of-the-art atomic clocks, so called optical clocks, traditional means of disseminating their signals without degrading their performance are no longer adequate. The implementation of a new technology for such purposes has in recent years been implemented in several countries around the world, which utilizes optical bers as a medium to transfer and compare the signals of the atomic frequency references.In this thesis, I discuss the exploitation of such an optical ber network in France. I discuss the general noise processes of such ber links, and their technical and fundamental limits. In-depth studies of several applications of a ber network is presented. These include the evaluation of the uncertainty contribution of the French ber network to the comparison of optical clocks. I also show studies of the use of ber networks for the sensing of e ects arising from the Earth. This includes the sensing of the Sagnac e ect in a ber link deployed in a ring topology around Paris, a study of the detection of earthquakes with the French ber network, and a discussion of the prospects of the use of such a technology.Les horloges atomiques sont les outils modernes de la mesure du temps. Depuis la redeÌfinition de la seconde en 1967 fondeÌe sur lâinterrogation dâune transition atomique du CeÌsium 133, les horloges atomiques se sont consideÌrablement ameÌlioreÌes. Cela a conduit aÌ de nombreuses avanceÌes technologiques au cours des 55 dernieÌres anneÌes, dont beaucoup neÌcessitent un transfert preÌcis des signaux de temps et de freÌquence, un exemple important eÌtant le systeÌme de positionnement global (GPS). Avec les reÌcents progreÌs des horloges atomiques de dernieÌre geÌneÌration, dites optique, les moyens traditionnels de diffusion des signaux dâhorloge(s) ne sont plus adapteÌs si on nâaccepte pas de ne pas deÌgrader leurs performances. La mise en Ćuvre dâune nouvelle technologie a eÌteÌ deÌveloppeÌe aÌ cette fin dans plusieurs pays du monde ces dernieÌres anneÌes. Elle utilise les fibres optiques comme support pour transfeÌrer et comparer les signaux des reÌfeÌrences de freÌquence atomique. Dans cette theÌse, jâaborderai la mise en Ćuvre dâun reÌseau de fibres optiques en France. Je discuterai des processus geÌneÌraux de bruit de ces liaisons par fibre optique, et de leurs limites techniques et fondamentales. Des eÌtudes approfondies de plusieurs applications dâun reÌseau de fibres sont preÌsenteÌes. Celles-ci incluent lâeÌvaluation de la contribution de lâincertitude du reÌseau français de fibres optiques aÌ la comparaison des horloges optiques. Ensuite, je preÌsenterai une eÌtudes sur lâutilisation de reÌseaux de fibres pour la deÌtection de pheÌnomeÌnes geÌophysiques. Cela inclut la deÌtection de lâeffet Sagnac dans un lien aÌ fibre deÌployeÌ dans une topologie en anneau autour de Paris. Ensuite, je montrerai une eÌtude de la deÌtection des tremblements de terre avec le reÌseau de fibres français, et je discuterai des perspectives dâutilisation dâune telle technologie
Réseaux de liens fibrés en métrologie pour la dissémination de fréquence : étude, exploitation, et sensibilités à l'effet Sagnac et autres perturbations terrestres
Atomic clocks are the modern tools of timekeeping. Ever since the rede nition of the second in 1967 based on an atomic transition of Cesium 133, the atomic clocks have improved drastically. This has lead to many technological advancements the last 55 years, many of which require precise transfer of time and frequency signals, a prominent example being the Global Positioning System (GPS). With the recent advancements of the last generation of state-of-the-art atomic clocks, so called optical clocks, traditional means of disseminating their signals without degrading their performance are no longer adequate. The implementation of a new technology for such purposes has in recent years been implemented in several countries around the world, which utilizes optical bers as a medium to transfer and compare the signals of the atomic frequency references.In this thesis, I discuss the exploitation of such an optical ber network in France. I discuss the general noise processes of such ber links, and their technical and fundamental limits. In-depth studies of several applications of a ber network is presented. These include the evaluation of the uncertainty contribution of the French ber network to the comparison of optical clocks. I also show studies of the use of ber networks for the sensing of e ects arising from the Earth. This includes the sensing of the Sagnac e ect in a ber link deployed in a ring topology around Paris, a study of the detection of earthquakes with the French ber network, and a discussion of the prospects of the use of such a technology.Les horloges atomiques sont les outils modernes de la mesure du temps. Depuis la redĂ©finition de la seconde en 1967 fondĂ©e sur lâinterrogation dâune transition atomique du CĂ©sium 133, les horloges atomiques se sont considĂ©rablement amĂ©liorĂ©es. Cela a conduit Ă de nombreuses avancĂ©es technologiques au cours des 55 derniĂšres annĂ©es, dont beaucoup nĂ©cessitent un transfert prĂ©cis des signaux de temps et de frĂ©quence, un exemple important Ă©tant le systĂšme de positionnement global (GPS). Avec les rĂ©cents progrĂšs des horloges atomiques de derniĂšre gĂ©nĂ©ration, dites optique, les moyens traditionnels de diffusion des signaux dâhorloge(s) ne sont plus adaptĂ©s si on nâaccepte pas de ne pas dĂ©grader leurs performances. La mise en Ćuvre dâune nouvelle technologie a Ă©tĂ© dĂ©veloppĂ©e Ă cette fin dans plusieurs pays du monde ces derniĂšres annĂ©es. Elle utilise les fibres optiques comme support pour transfĂ©rer et comparer les signaux des rĂ©fĂ©rences de frĂ©quence atomique. Dans cette thĂšse, jâaborderai la mise en Ćuvre dâun rĂ©seau de fibres optiques en France. Je discuterai des processus gĂ©nĂ©raux de bruit de ces liaisons par fibre optique, et de leurs limites techniques et fondamentales. Des Ă©tudes approfondies de plusieurs applications dâun rĂ©seau de fibres sont prĂ©sentĂ©es. Celles-ci incluent lâĂ©valuation de la contribution de lâincertitude du rĂ©seau français de fibres optiques Ă la comparaison des horloges optiques. Ensuite, je prĂ©senterai une Ă©tudes sur lâutilisation de rĂ©seaux de fibres pour la dĂ©tection de phĂ©nomĂšnes gĂ©ophysiques. Cela inclut la dĂ©tection de lâeffet Sagnac dans un lien Ă fibre dĂ©ployĂ© dans une topologie en anneau autour de Paris. Ensuite, je montrerai une Ă©tude de la dĂ©tection des tremblements de terre avec le rĂ©seau de fibres français, et je discuterai des perspectives dâutilisation dâune telle technologie
An accurate and robust metrological network for coherent optical frequency dissemination
International audienceWe introduce multi branch repeater laser stations (MLSs) for the dissemination of an ultra stable signal from one point to multiple users and the simultaneous evaluation of the stability and accuracy of multiple links. We perform the study of the noise floor of this new instrument. We present then an optical fiber network of 4800 km built with three MLSs and 13 repeater laser stations (RLSs). We show the multi user optical frequency dissemination on four links totalizing 2198 km with uncertainties below 1.1Ă10 19. The robustness of the network over two years is presented and stability and accuracy at 107 seconds integration time are finally showed
Coherent fiber links operated for years: effect of missing data
International audienceAiming at delivering a highly available service, the French national optical fiber link network is run mostly unmanned and automatically, with the help of a global supervision. However, at a year scale, missing data are seemingly unavoidable. Here, we present a first study of the uncertainty of coherent fiber links with missing data. We present the tools to assess statistical properties for processes which are not strictly stationary, and a simulation of optical fiber links depending only on a handful of parameters. We show how missing data affects the phase-coherent optical fiber links, and how to mitigate the issue with a fill-in procedure that preserves the statistical properties. We apply the method for a 5 years-long data set of a 1410 km long fiber link. Second, we apply the method to the case of optical clock comparisons, where the downtimes of the optical clocks degrade the coherence of the links. We show that our methodology of processing the missing data is robust and converges to consistent mean values, even with very low uptimes. We present an offset and uncertainty contribution from the French fiber network of 2.4(9.0) Ă 10 â20 , that is an improvement by a factor 5 as compared to a processing without taking the effect of missing data into account
REFIMEVE Fiber Network for Time and Frequency Dissemination and Applications
International audienc
Atomic clock dataset for 'Coherent Optical-Fiber Link Across Italy and France'
Dataset of the comparison of the atomic clocks at LNE-SYRTE and INRIM via optical fibre link between October 2021 and February 2022. Results discussed in Clivati et al., Coherent Optical-Fiber Link Across Italy and France, Phys. Rev. Applied, American Physical Society, 18, 054009, 2022.
The involved atomic clocks are the Cs fountains SYRTE-F02Cs, IT-CsF2, the Rb fountain SYRTE-F02Rb and the Yb optical lattice clock IT-Yb1.
Data is organized in folders, one for each comparison. In the folders data is separated is one file per day. Data is reported as fractional frequency ratios in bins of 864 s. Timetags are reported in modified Julian date (MJD). A validity flag is given where 0 = invalid, valid otherwise. Each folder includes a yaml file with metadata required for generalized data processing as in [Lodewyck et al., 2020]. The Python package used for data processing can be found on github.This work was supported by: the European Metrology Program for Innovation and Research (EMPIR) Projects 18SIB05 ROCIT, 18SIB06 TIFOON, 20FUN08 NextLasers, which received funding from the EMPIR programme co-financed by the Participating States and from the European Union's Horizon 2020 research and innovation programme; the European Union's Horizon 2020 research and innovation programme under Grant
Agreement No. 951886 (CLONETS-DS); Program "Investissements d'Avenir" launched by the French Government and implemented by Agence Nationale de la Recherche with references ANR-10-LABX-48-01 (Labex First-TF), ANR-21-ESRE-0029 (ESR/Equipex T-REFIMEVE), ANR-11-EQPX-0039 (Equipex REFIMEVE+), ANR-10-IDEX-0001-002 (Idex PSL);
Conseil RĂ©gional Bourgogne-Franche-ComtĂ©; Domaine d'IntĂ©rĂȘt Majeur Science et IngĂ©nierie en RĂ©gion Ăle-de-France pour les Technologies Quantiques (DIM SIRTEQ)
A Coherent Optical Fibre Link Between France and Italy
International audienceWe report on the results obtained with the recently developed fiber link between LNE-SYRTE in France and INRIM in Italy. The link enables comparisons of different species of clocks, including Cs and Rb fountains, Sr and Yb optical lattice clocks, providing data to the roadmap for the redefinition of the second in the International System of Units