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101. Correction of the distortion in frequency modulation spectroscopy

Author

F du Burck and Olivier Lopez

Subjects
Pulse-frequency modulation, Materials science, business.industry, Applied Mathematics, Residual, Signal, Amplitude modulation, Optics, Modulation, Distortion, business, Saturation (chemistry), Spectroscopy, Instrumentation, Engineering (miscellaneous)
Abstract

A theoretical expression for the detected signal in frequency modulation spectroscopy with a residual amplitude modulation (RAM) is computed. The line shape distortion induced by the RAM is shown to be essentially suppressed for a proper choice of the modulation and detection parameters. The experimental tests are carried out in saturation spectroscopy of I2 at 514.5 nm. Experimental limitations are analysed.

Published
2004
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102. Absolute frequency measurement of the iodine-stabilized Ar+ laser at 514.6 nm using a femtosecond optical frequency comb

Author

Anne Amy-Klein, C. Chardonnet, Andrei Goncharov, Olivier Lopez, and F. du Burck

Subjects
Materials science, Optical fiber, Argon, Physics and Astronomy (miscellaneous), business.industry, General Engineering, General Physics and Astronomy, Comb generator, chemistry.chemical_element, Laser, law.invention, Optics, chemistry, law, Femtosecond, Maser, business, Ultrashort pulse, Hyperfine structure
Abstract

The frequency of 127I2 hyperfine component a3 of the P(13) 43-0 transition at 514.6 nm has been measured with an optical clockwork based on a femtosecond laser frequency comb generator. The measured frequency at an iodine pressure of 0.12 Pa is 67.3(0.75) kHz higher than the value of 582490603.38(15) MHz, adopted by the CIPM in 2003 [9] but is in a good agreement with the value measured by [29]. In our experiment we used H-maser reference frequency located at BNM-SYRTE Observatoire de Paris and transported to our laboratory by a 43 km optical fibre link.

Published
2004
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103. Cascaded optical link on a telecommunication fiber network for ultra-stable frequency dissemination

Author

Paul-Eric Pottie, Olivier Lopez, Nicola Chiodo, Nicolas Quintin, Fabrice Wiotte, Christian Chardonnet, Fabio Stefani, Giorgio Santarelli, Anthony Bercy, and Anne Amy-Klein

Subjects
Optical fiber, Computer science, Optical link, Fiber network, Passive optical network, law.invention, time-frequency metrology, law, Wavelength-division multiplexing, Electronic, optical clocks, Optical and Magnetic Materials, Fiber, Electrical and Electronic Engineering, Repeater, business.industry, Applied Mathematics, Amplifier, phase stabilization, Bandwidth (signal processing), Computer Science Applications1707 Computer Vision and Pattern Recognition, Particle accelerator, optical link, Electronic, Optical and Magnetic Materials, Condensed Matter Physics, Metrology, Telecommunications, business
Abstract

The transfer of ultra-stable frequencies between distant laboratories is required by many applications in time and frequency metrology, fundamental physics, particle accelerators and astrophysics. Optical fiber links have been intensively studied for a decade and brought the potential to transfer frequency with a very high accuracy and stability thanks to an active compensation of the propagation noise. We are currently developing an optical metrological network using the fibers of the French National Research and Education Network. Using the so-called dark-channel approach, the ultrastable signal is copropagating with data traffic using wavelength division multiplexing. Due to significant reflections and losses along the fibers, which cannot be compensated with amplifiers, we have developed some repeater stations for the metrological signal. These remotely-operated stations amplify the ultrastable signal and compensate the propagation noise. The link is thus composed of a few cascaded spans. It gives the possibility to increase the noise correction bandwidth, which is proportional to the inverse of the fiber length for each span. These stations are a key element for the deployment of a reliable and large scale metrological network. We report here on the implementation of a two-spans cascaded link of 740 km reaching a relative stability of a few 10-20 after 103 s averaging time. Extension to longer links and alternative transfer methods will be discussed. © (2015) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.

Published
2015
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104. Modeling the Dependence between Extreme Operational Losses and Economic Factors: A Conditional Semi-Parametric Generalized Pareto Approach

Author

Julien Hambuckers, Cédric Heuchenne, and Olivier Lopez

Subjects
Mathematical optimization, symbols.namesake, Pareto interpolation, Generalized Pareto distribution, Econometrics, Nonparametric statistics, symbols, Lomax distribution, Semiparametric regression, Pareto distribution, Parametric statistics, Semiparametric model, Mathematics
Abstract

We model the severity distribution of operational loss data, conditionally to some covariates. Indeed, previous studies suggest that this distribution might be influenced by firm-specific factors. We introduce a conditional Generalized Pareto model for the tail of the severity distribution, where the shape parameter is an unknown function of a linear combination of the covariates. More precisely, we rely on a single-index assumption to perform a dimension reduction that enables to use univariate nonparametric techniques. Hence, we suffer neither from too strong parametric assumption nor from the curse of dimensionality. We apply this methodology on a novel database provided by the bank UniCredit. We use firm-specific factors to estimate the conditional shape parameter. Our analysis suggests that the leverage ratio of the company and the proportion of the revenue coming from fees have an important impact on the probability of suffering from large operational losses.

Published
2015
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105. Coral Fishermen in Barbary in the Eighteenth Century: Between Norms and Practices

Author

Olivier Lopez, Temps, espaces, langages Europe méridionale-Méditerranée (TELEMME), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), Aix Marseille Université (AMU), Maria Fusaro, Bernard Allaire, Richard Blakemore & Tijl Vanneste (eds), Lopez, Olivier, and Maria Fusaro, Bernard Allaire, Richard Blakemore & Tijl Vanneste (eds)

Subjects
Politics, Geography, State (polity), Economy, Multinational corporation, media_common.quotation_subject, [SHS.HIST] Humanities and Social Sciences/History, Professional environment, North african, Monopoly, [SHS.HIST]Humanities and Social Sciences/History, Archaeology, media_common
Abstract

As itinerant, multinational labourers, seamen fully deserve the analytical attention they have received throughout this volume. This is not to say, however, that they (in addition to merchants and political personnel such as consuls) were the only relevant actors in the development of connections in the early modern Mediterranean. Other groups of workers were active in occupations linked to the same commercial activities which provided employment for sailors, and promoted interaction between physically and culturally distant communities. Fishermen, coming from different backgrounds and working for some of the French companies trading in coral from the waters of the North African coast, provide but one example of this. This chapter will investigate their professional environment, arguing that these fishermen were at the same time agents promoting French imperial interests in the Mediterranean, as well as sometimes challenging the very monopoly underlying such state efforts.

Published
2015

106. Semiparametric inference for the recurrent event process by means of a single-index model

Author

Olivier Bouaziz, Ségolen Geffray, Olivier Lopez, Mathématiques Appliquées Paris 5 (MAP5 - UMR 8145), Université Paris Descartes - Paris 5 (UPD5)-Institut National des Sciences Mathématiques et de leurs Interactions (INSMI)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche Mathématique Avancée (IRMA), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), Centre de Recherche en Économie et Statistique (CREST), Ecole Nationale de la Statistique et de l'Analyse de l'Information [Bruz] (ENSAI)-École polytechnique (X)-École Nationale de la Statistique et de l'Administration Économique (ENSAE ParisTech )-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Statistique Théorique et Appliquée (LSTA), Université Pierre et Marie Curie - Paris 6 (UPMC), Mathématiques Appliquées à Paris 5 ( MAP5 - UMR 8145 ), Université Paris Descartes - Paris 5 ( UPD5 ) -Institut National des Sciences Mathématiques et de leurs Interactions-Centre National de la Recherche Scientifique ( CNRS ), Institut de Recherche Mathématique Avancée ( IRMA ), Université de Strasbourg ( UNISTRA ) -Centre National de la Recherche Scientifique ( CNRS ), Centre de Recherche en Économie et Statistique ( CREST ), Ecole Nationale de la Statistique et de l'Analyse de l'Information [Bruz] ( ENSAI ) -École polytechnique ( X ) -École Nationale de la Statistique et de l'Administration Économique ( ENSAE ParisTech ), Laboratoire de Statistique Théorique et Appliquée ( LSTA ), Université Pierre et Marie Curie - Paris 6 ( UPMC ), Ecole Nationale de la Statistique et de l'Analyse de l'Information [Bruz] (ENSAI)-École polytechnique (X)-École Nationale de la Statistique et de l'Administration Économique (ENSAE Paris)-Centre National de la Recherche Scientifique (CNRS), and Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Statistics and Probability, Statistics::Theory, dimension reduction, asymptotic normality, Asymptotic distribution, Mathematics - Statistics Theory, Statistics Theory (math.ST), [MATH.MATH-ST]Mathematics [math]/Statistics [math.ST], single-index model, Econometrics, FOS: Mathematics, Statistics::Methodology, Semiparametric regression, [ MATH.MATH-ST ] Mathematics [math]/Statistics [math.ST], Parametric statistics, Mathematics, empirical processes, Dimensionality reduction, Nonparametric statistics, Estimator, [STAT.TH]Statistics [stat]/Statistics Theory [stat.TH], [ STAT.TH ] Statistics [stat]/Statistics Theory [stat.TH], right-censoring, Semiparametric model, recurrent events, Statistics, Probability and Uncertainty, Curse of dimensionality
Abstract

International audience; In this paper, we introduce new parametric and semiparametric regression techniques for a recurrent event process subject to random right censoring. We develop models for the cumula- tive mean function and provide asymptotically normal estimators. Our semiparametric model which relies on a single-index assumption can be seen as a dimension reduction technique that, contrary to a fully nonparametric approach, is not stroke by the curse of dimensional- ity when the number of covariates is high. We discuss data-driven techniques to choose the parameters involved in the estimation procedures and provide a simulation study to support our theoretical results.

Published
2015
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107. Two-way optical frequency comparisons at5×10−21relative stability over 100-km telecommunication network fibers

Author

Fabio Stefani, Paul-Eric Pottie, Anne Amy-Klein, Olivier Lopez, Christian Chardonnet, and Anthony Bercy

Subjects
Physics, Time delay and integration, Mode volume, Optical link, Digital data, Electronic engineering, Fiber, Stability (probability), Telecommunications network, Noise (electronics), Atomic and Molecular Physics, and Optics
Abstract

By using two-way frequency transfer, we demonstrate ultra-high resolution comparison of optical frequencies over a telecommunication fiber link of 100 km operating simultaneously digital data transfer. We first propose and experiment a bi-directional scheme using a single fiber. We show that the relative stability at 1 s integration time is 7 10^18 and scales down to 5 10^21. The same level of performance is reached when an optical link is implemented with an active compensation of the fiber noise. We also implement a real-time two-way frequency comparison over a uni-directional telecommunication network using a pair of parallel fibers. The relative frequency stability is 10^15 at 1 s integration time and reaches 2 10^17 at 40 000 s. The fractional uncertainty of the frequency comparisons was evaluated for the best case to 2 10^20. These results open the way to accurate and high resolution frequency comparison of optical clocks over intercontinental fiber networks.

Published
2014
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108. Quantum Cascade Laser at Hz-Level by Use of a Frequency Comb and an Optical Link

Author

Bruno Chanteau, C. Chardonnet, Olivier Lopez, M. Abgrall, B. Argence, Anne Amy-Klein, Christophe Daussy, Daniele Nicolodi, Benoît Darquié, Y. Le Coq, Systèmes de Référence Temps Espace (SYRTE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Métrologie des fréquences optiques, Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Distributed feedback laser, Materials science, business.industry, Optical link, Far-infrared laser, Laser, Signal, law.invention, Frequency comb, Optics, law, Quantum cascade laser, business, Spectroscopy, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

International audience; We present a frequency chain which enables to transfer coherently the stability and the accuracy of an ultrastable laser emitting at 1.54 mu m to the mid-infrared region. It includes an optical frequency comb and an ultrastable 1.54 mu m frequency signal, referenced to primary standards and transferred from LNE-SYRTE to LPL through an optical link. This system gives us the ability to transfer frequency stability in the range of 10(-15) and accuracy in the range of 10(-14) from 1.54 mu m to a wide spectral range in the mid-infrared domain. With this set-up, we stabilized a Quantum Cascade Laser emitting at 10.3 mu m at an unprecedented Hz-level.

Published
2014
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109. Ultra-stable Mid-IR quantum cascade laser for high-resolution spectroscopy and metrology

Author

Benoît Darquié, Anne Amy-Klein, Andrei Goncharov, Olivier Lopez, Christian Chardonnet, S. Mejri, P. L. T. Sow, B. Argence, S. K. Tokunaga, and Christophe Daussy

Subjects
Distributed feedback laser, Tunable diode laser absorption spectroscopy, Materials science, Absorption spectroscopy, Physics::Instrumentation and Detectors, business.industry, Far-infrared laser, Saturated absorption spectroscopy, Physics::Optics, Laser, law.invention, Optics, law, Quantum dot laser, Optoelectronics, business, Quantum cascade laser
Abstract

We report the phase-locking of a quantum cascade laser (QCL) at 10 μm to the secondary frequency standard of this spectral region, a CO2 laser stabilized on a saturated absorption line of OsO4. The stability and accuracy of the standard are transferred to the QCL resulting in a line width of the order of 10 Hz. The locked QCL is then used to perform high-resolution linear and saturated absorption spectroscopy of species of interest for applications in precision measurements.

Published
2014
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110. A widely tunable 10-$\mu$m quantum cascade laser phase-locked to a state-of-the-art mid-infrared reference for precision molecular spectroscopy

Author

Benoît Darquié, S. Mejri, Anne Amy-Klein, B. Argence, Sean Tokunaga, Christophe Daussy, Olivier Lopez, Christian Chardonnet, Papa Lat Tabara Sow, and Andrey Goncharov

Subjects
Materials science, Secondary frequency standard, Physics and Astronomy (miscellaneous), Absorption spectroscopy, business.industry, Phase (waves), Laser, 01 natural sciences, Spectral line, 3. Good health, law.invention, Physics - Atomic Physics, 010309 optics, law, 0103 physical sciences, Optoelectronics, 010306 general physics, Spectroscopy, Quantum cascade laser, Absorption (electromagnetic radiation), business, Physics - Optics
Abstract

We report the coherent phase-locking of a quantum cascade laser (QCL) at 10-$\mu$m to the secondary frequency standard of this spectral region, a CO2 laser stabilized on a saturated absorption line of OsO4. The stability and accuracy of the standard are transferred to the QCL resulting in a line width of the order of 10 Hz, and leading to our knowledge to the narrowest QCL to date. The locked QCL is then used to perform absorption spectroscopy spanning 6 GHz of NH3 and methyltrioxorhenium, two species of interest for applications in precision measurements., Comment: 5 pages, 4 figures

Published
2014

111. Non-Parametric Estimation of Linear Functionals of a Multivariate Distribution Under Multivariate Censoring with Applications

Author

Philippe Saint-Pierre, Olivier Lopez, Laboratoire de Physique des Lasers (LPL), Université Paris 13 (UP13)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Statistique Théorique et Appliquée (LSTA), Université Pierre et Marie Curie - Paris 6 (UPMC), and Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Multivariate statistics, 05 social sciences, Inverse-Wishart distribution, Matrix t-distribution, [STAT.TH]Statistics [stat]/Statistics Theory [stat.TH], 01 natural sciences, Multivariate kernel density estimation, Normal-Wishart distribution, 010104 statistics & probability, 0502 economics and business, Statistics, Matrix normal distribution, Multivariate t-distribution, 0101 mathematics, [STAT.ME]Statistics [stat]/Methodology [stat.ME], ComputingMilieux_MISCELLANEOUS, 050205 econometrics, Mathematics, Multivariate stable distribution
Abstract

International audience

Published
2014

112. Progress on a cascaded optical link between Paris and Strasbourg

Author

Christian Chardonnet, Olivier Lopez, Anne Amy-Klein, Paul-Eric Pottie, Nicolas Quintin, Giorgio Santarelli, Fabio Stefani, Fabrice Wiotte, Anthony Bercy, and Nicola Chiodo

Subjects
Multiwavelength optical networking, Repeater, frequency transfer, phase-lock loop, optical link, frequency transfer, fiber optics, Repeaters, Optical fiber networks, Optical fiber amplifiers, wavelength division multiplexing, business.industry, Computer science, Optical link, Electrical engineering, Optical performance monitoring, phase-lock loop, Passive optical network, Frequency-division multiplexing, Repeaters, Wavelength-division multiplexing, Optical fiber networks, Optical fiber amplifiers, optical link, Telecommunications, business, wavelength division multiplexing, Optical communications repeater, fiber optics
Abstract

We are currently developing a cascaded optical frequency link between Paris and Strasbourg using the French National Research and Education Network RENATER. The ultrastable signal is copropagating with data traffic using wavelength division multiplexing. We have developed some repeater stations to amplify and filter the ultrastable signal between each sections of the link and compensate the propagation noise. The remote operation of these stations is a key element for the deployment of a reliable and large scale metrological network. We report on the first implementation of such a remote station on a 540-km cascaded link between Paris and Reims. The stability (modified Allan deviation with Λ-type counter) reaches a few 10−20 at 103 s averaging time.

Published
2014

113. In-line extraction of an ultrastable frequency signal over an optical fiber link

Author

Fabio Stefani, Christian Chardonnet, Paul-Eric Pottie, Giorgio Santarelli, Anthony Bercy, Olivier Lopez, Anne Amy-Klein, Saida Guellati, MMTF, Laboratoire de Physique des Lasers (LPL), Université Paris 13 (UP13)-Centre National de la Recherche Scientifique (CNRS)-Université Paris 13 (UP13)-Centre National de la Recherche Scientifique (CNRS)-Systèmes de Référence Temps Espace (SYRTE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Université Paris 13 (UP13)-Centre National de la Recherche Scientifique (CNRS)-Université Sorbonne Paris Nord, Métrologie des systèmes simples et tests fondamentaux / Metrology of Simple Systems and Fundamental Tests, Laboratoire Kastler Brossel (LKB (Jussieu)), Fédération de recherche du Département de physique de l'Ecole Normale Supérieure - ENS Paris (FRDPENS), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Fédération de recherche du Département de physique de l'Ecole Normale Supérieure - ENS Paris (FRDPENS), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Université Paris 13 (UP13)-Centre National de la Recherche Scientifique (CNRS), Systèmes de Référence Temps Espace (SYRTE), lp2n-06, Laboratoire Photonique, Numérique et Nanosciences (LP2N), Université de Bordeaux (UB)-Institut d'Optique Graduate School (IOGS)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB)-Institut d'Optique Graduate School (IOGS)-Centre National de la Recherche Scientifique (CNRS), Université Paris 13 (UP13)-Centre National de la Recherche Scientifique (CNRS)-Université Paris 13 (UP13)-Centre National de la Recherche Scientifique (CNRS), Agence Nationale de la Recherche (ANR BLANC 2011-BS04-009-01), Labex First-TF (ANR-10-LABX-48-01), the European Metrology Research Programme (EMRP) under contract SIB-02 NEAT-FT and IFRAF-Conseil Régional Ile-de-France., European Project, Centre National de la Recherche Scientifique (CNRS)-Université Sorbonne Paris Nord, Université Pierre et Marie Curie - Paris 6 (UPMC)-Fédération de recherche du Département de physique de l'Ecole Normale Supérieure - ENS Paris (FRDPENS), Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Fédération de recherche du Département de physique de l'Ecole Normale Supérieure - ENS Paris (FRDPENS)

Subjects
Computer science, Optical link, Optical engineering, optical links, Metrology, 01 natural sciences, (120.3930) Metrological instrumentation, (060.2360) Fiber optics links and subsystems, (140.0140) Lasers and laser optics, (120.5050) Phase measurement, Optical fiber networks, High resolution spectroscopy, wide area networks, Fiber optic splitter, Electronic, Optical and Magnetic Materials, Mechanics of Materials, Plastic optical fiber, optical fibre networks, Instrumentation, Ultrastable laser, Optical link, frequency transfer , Phase noise, Optical fiber couplers, Optical fiber networks, Adaptive optics, wide area networks, optical fibre networks, optical links, multiuser dissemination, ultrastable frequency signal, inline extraction, optical fiber link, optical frequency standard, France, metrological fibre wide-area network, frequency transfer, Quantum Physics, [PHYS.PHYS.PHYS-OPTICS]Physics [physics]/Physics [physics]/Optics [physics.optics], Measurement, Multi-mode optical fiber, Optical cross-connect, Phase measurement, optical fiber link, Atomic and Molecular Physics, and Optics, Ultrastable laser, inline extraction, ultrastable frequency signal, France, Physics - Optics, optical fiber links, Signal processing, metrological fibre wide-area network, Optical fiber couplers, Laser stability, FOS: Physical sciences, Metrological instrumentation, 010309 optics, multiuser dissemination, Optics, [PHYS.QPHY]Physics [physics]/Quantum Physics [quant-ph], Power spectral density, 0103 physical sciences, Electronic, Electronic engineering, Optical fibers, Optical and Magnetic Materials, 010306 general physics, optical frequency standard, business.industry, Phase noise, Statistical and Nonlinear Physics, Optical performance monitoring, Fiber-optic communication, Instrumentation, Measurement, Metrology, High resolution spectroscopy, Laser stability, Optical fibers, Phase noise, Power spectral density, Signal processing, extraction, business, Quantum Physics (quant-ph), Adaptive optics, Optics (physics.optics)
Abstract

International audience; We demonstrate in-line extraction of an ultra-stable frequency signal over an optical link of 92-km of installed telecommunication fibers, following the proposition of G. Grosche in 2010. We show that the residual frequency noise at the extraction end is noticeably below that at the main link output when the extraction is near the input end, as expected from a simple model of the noise compensation. We obtain relative frequency instabilities, expressed as overlapping Allan deviation, of 8×10-16 at 1 s averaging time and a few 10-19 at 1 day. These results are at the state-of-the-art for a link using urban telecommunication fibers. We also propose an improved scheme which delivers an ultra-stable signal of higher power, in order to feed a secondary link. In-line extraction opens the way to a broad distribution of an ultra-stable frequency reference, enabling a wide range of applications beyond metrology.

Published
2014
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114. Single index regression models in the presence of censoring depending on the covariates

Author

Valentin Patilea, Ingrid Van Keilegom, Olivier Lopez, Laboratoire de Statistique Théorique et Appliquée (LSTA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche Mathématique de Rennes (IRMAR), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-École normale supérieure - Rennes (ENS Rennes)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-INSTITUT AGRO Agrocampus Ouest, Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro), Institute of Statistics, Université Catholique de Louvain = Catholic University of Louvain (UCL), European Project: 203650,EC:FP7:ERC,ERC-2007-StG,MAZEST(2008), Université Pierre et Marie Curie - Paris 6 (UPMC), AGROCAMPUS OUEST, Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Université de Rennes 2 (UR2), Université de Rennes (UNIV-RENNES)-École normale supérieure - Rennes (ENS Rennes)-Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA), Université de Paris VI - Laboratoire de Statistique Théorique et Appliquée, and UCL - EUEN/STAT - Institut de statistique

Subjects
Statistics and Probability, Multivariate distribution, Multivariate random variable, Single-index model, dimension reduction, semiparametric regression, Mathematics - Statistics Theory, Statistics Theory (math.ST), 01 natural sciences, survival analysis, 010104 statistics & probability, Curse-of-dimensionality, Joint probability distribution, [MATH.MATH-ST]Mathematics [math]/Statistics [math.ST], 0502 economics and business, Covariate, FOS: Mathematics, Applied mathematics, 0101 mathematics, 050205 econometrics, Mathematics, Right censoring, curse-of-dimensionality, 05 social sciences, Estimator, Semiparametric regression, Regression analysis, [STAT.TH]Statistics [stat]/Statistics Theory [stat.TH], Survival analysis, Censoring (statistics), Regression, right censoring, multivariate distribution, Dimension reduction
Abstract

Consider a random vector (X',Y)', where X is d-dimensional and Y is one-dimensional. We assume that Y is subject to random right censoring. The aim of this paper is twofold. First, we propose a new estimator of the joint distribution of (X',Y)'. This estimator overcomes the common curse-of-dimensionality problem, by using a new dimension reduction technique. Second, we assume that the relation between X and Y is given by a mean regression single index model, and propose a new estimator of the parameters in this model. The asymptotic properties of all proposed estimators are obtained., Published in at http://dx.doi.org/10.3150/12-BEJ464 the Bernoulli (http://isi.cbs.nl/bernoulli/) by the International Statistical Institute/Bernoulli Society (http://isi.cbs.nl/BS/bshome.htm)

Published
2013
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115. Towards large scale metrological fibre network

Author

Anthony Bercy, Giorgio Santarelli, Paul-Eric Pottie, Fabio Stefani, Anne Amy-Klein, Olivier Lopez, Christian Chardonnet, Systèmes de Référence Temps Espace (SYRTE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Métrologie des fréquences optiques, Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Engineering, business.industry, Scale (chemistry), Optical link, Frame (networking), Fiber network, Metrology, frequency transfert, ultrastable laser, Control and Systems Engineering, Optical frequencies, Systems engineering, Electronic engineering, business, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

In the frame of the REFIMEVE+ project, aiming at disseminating an optical frequency standard to more than 20 laboratories in France, we present the progress made towards a metrological fibre wide-area network.

Published
2013
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116. Long distance phase-coherent link between near- and mid-infrared frequencies

Author

C. Chardonnet, Y. Le Coq, M. Abgrall, B. Chanteau, Benoît Darquié, B. Argence, Olivier Lopez, Giorgio Santarelli, Christophe Daussy, Daniele Nicolodi, and Anne Amy-Klein

Subjects
Physics, Distributed feedback laser, business.industry, Far-infrared laser, Phase (waves), Laser, Atomic fountain, Atomic clock, law.invention, Optics, law, Laser power scaling, business, Laser Doppler vibrometer, Astrophysics::Galaxy Astrophysics
Abstract

We present a new method for accurate mid-infrared frequency measurements and stabilization to a near-infrared ultra-stable frequency reference, transmitted with a long-distance fibre link and continuously monitored against state-of-the-art atomic fountain clocks. We demonstrate the frequency stabilization of a mid-infrared laser with fractional stability better than 4×10-14 at 1 s averaging. This new stabilization scheme gives us the ability to transfer frequency stability in the range of 10-15 or even better, currently accessible in the near-infrared or in the visible, to mid-infrared lasers in a wide frequency range.

Published
2013
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117. Ultra-stable long distance optical frequency distribution using the Internet fiber network and application to high-precision molecular spectroscopy

Author

Michel Abgrall, Bruno Chanteau, Paul-Eric Pottie, Anthony Bercy, Daniele Rovera, B. Argence, Daniele Nicolodi, C. Chardonnet, Joseph Achkar, Amale Kanj, Benoît Darquié, Y. Le Coq, Wei Zhang, A. Haboucha, Giorgio Santarelli, Olivier Lopez, Anne Amy-Klein, Laboratoire de Physique des Lasers (LPL), Université Paris 13 (UP13)-Centre National de la Recherche Scientifique (CNRS)-Université Sorbonne Paris Nord, Systèmes de Référence Temps Espace (SYRTE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Métrologie des fréquences optiques, Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Références micro-ondes et échelles de temps, Laboratoire Photonique, Numérique et Nanosciences (LP2N), and Université de Bordeaux (UB)-Institut d'Optique Graduate School (IOGS)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, History, business.industry, Optical link, Bandwidth (signal processing), Rotational–vibrational spectroscopy, Laser, Computer Science Applications, Education, law.invention, Optics, law, Electronic engineering, Time transfer, The Internet, business, Spectroscopy, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Order of magnitude
Abstract

International audience; We report an optical link of 540 km for ultrastable frequency distribution over the Internet fiber network. The phase-noise compensated link shows a fractional frequency instability in full bandwidth of 3×10-14 at one second measurement time and 2×10-18 at 30 000 s. This work is a significant step towards a sustainable wide area ultrastable optical frequency distribution and comparison network. Time transfer was demonstrated simultaneously on the same link and led to an absolute time accuracy (250 ps) and long-term timing stability (20 ps) which outperform the conventional satellite transfer methods by one order of magnitude. Current development addresses the question of multiple users distribution in the same metropolitan area. We demonstrate on-line extraction and first results show frequency stability at the same level as with conventional link. We also report an application to coherent frequency transfer to the mid-infrared. We demonstrate the frequency stabilisation of a mid-infrared laser to the near-infrared frequency reference transferred through the optical link. Fractional stability better than 4×10-14 at 1 s averaging time was obtained, opening the way to ultrahigh resolution spectroscopy of molecular rovibrational transitions.

Published
2013
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118. Quantum cascade laser spectrometer for frequency metrology and high accuracy molecular spectroscopy around 10 μm

Author

Benoît Darquié, Sean Tokunaga, C. Chardonnet, Bruno Chanteau, Olivier Lopez, Andrei Goncharov, Anne Amy-Klein, Christophe Daussy, S. Mejri, B. Argence, and P. L. T. Sow

Subjects
Distributed feedback laser, Materials science, Spectrometer, business.industry, Far-infrared laser, Physics::Optics, law.invention, Metrology, Photomixing, Optics, Quantum dot laser, law, Optoelectronics, Quantum cascade laser, business, Tunable laser
Abstract

Quantum cascade lasers (QCLs) are an emerging technology [1] suitable for high-resolution spectrocopy and frequency metrology [2] with an incomparable frequency tunability in the mid-infrared range. We are currently developing a new compact, widely tunable QCL-based spectrometer. Such an instrument will broaden the scope of our experimental setups dedicated to molecular spectroscopy-based precision measurements.

Published
2013
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119. Validation of Digital Rock Physics Based Water-Oil Capillary Pressure and Saturation Exponents in Super Giant Carbonate Reservoirs

Author

Z. Kalam, Mohammad Al Hammadi, Alex Mock, Muhammad Antonia Gibrata, and Olivier Lopez

Subjects
chemistry.chemical_compound, Capillary pressure, chemistry, Mineralogy, Carbonate, Imbibition, Geotechnical engineering, Physics based, Drainage, Saturation (chemistry), Geology
Abstract

Digital Rock Physics (DRP) has progressed at a rapid speed since the first pore network models were developed. DRP has now evolved in to a new discipline and essentially involves use of X-ray CT scanning in micro and Nano-CT to capture the 3D network structure of representative reservoir rock types. The proliferation of the technique with powerful computers and robust network modeling means one can rapidly determine various Special Core Analysis (SCAL) properties that form the basis of reservoir characterization parameters: porosity, permeability, formation factor, cementation and saturation exponents, capillary pressure, relative permeability and elastic properties.A comprehensive DRP based validation study was performed on reservoir core plugs which had undergone rigorous Petrophysical SCAL at representative pseudo reservoir conditions. The objective was to assess the use of DRP in determining such data, and quantifying the relevant uncertainties. The plugs were chosen from two super giant carbonate reservoirs in the Middle East. The laboratory tests comprised cementation exponent ‘m’ at a range of pressures, water-oil capillary pressure (Pc) and electrical resistivity index (RI) tests at reservoir temperature and reservoir overburden pressure using specially designed Porous Plates.Capillary pressure under primary drainage and imbibition conditions, replicating reservoir conditions were established using multi-phase flow simulations on the pore network representation of the 3D rock model. Similarly, the cementation exponent ‘m’ was calculated using a solution of the Laplace equation with charge conservation; the equations were solved using a random walk algorithm. DRP based primary drainage and imbibition saturation exponents ‘n’ were also computed for cores samples of different reservoir rock types. The results were then compared to measured SCAL data, and validation criteria established along with possible uncertainties. DRP is extremely promising in generating fairly accurate SCAL parameters very fast from existing cores.

Published
2013
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120. Mid-infrared laser phase-locking to a remote near-infrared frequency reference for high precision molecular spectroscopy

Author

F. Auguste, Daniele Nicolodi, Michel Abgrall, Giorgio Santarelli, C. Chardonnet, Wei Zhang, B. Argence, Bruno Chanteau, Benoît Darquié, Olivier Lopez, Anne Amy-Klein, Y. Le Coq, Laboratoire de Physique des Lasers (LPL), Université Paris 13 (UP13)-Centre National de la Recherche Scientifique (CNRS), MMTF, Université Paris 13 (UP13)-Centre National de la Recherche Scientifique (CNRS)-Université Paris 13 (UP13)-Centre National de la Recherche Scientifique (CNRS), Laboratoire national de métrologie et d'essais - Systèmes de Référence Temps-Espace (LNE - SYRTE), Systèmes de Référence Temps Espace (SYRTE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), lp2n-06,lp2n-14, Laboratoire Photonique, Numérique et Nanosciences (LP2N), Université Sciences et Technologies - Bordeaux 1-Institut d'Optique Graduate School (IOGS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Institut d'Optique Graduate School (IOGS)-Centre National de la Recherche Scientifique (CNRS), ANR, CNRS, and Université Sciences et Technologies - Bordeaux 1 (UB)-Institut d'Optique Graduate School (IOGS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1 (UB)-Institut d'Optique Graduate School (IOGS)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Infrared, Atomic Physics (physics.atom-ph), General Physics and Astronomy, FOS: Physical sciences, 01 natural sciences, Atomic fountain, law.invention, Physics - Atomic Physics, 010309 optics, Laser linewidth, Optics, [PHYS.QPHY]Physics [physics]/Quantum Physics [quant-ph], law, 0103 physical sciences, 010306 general physics, Spectroscopy, Astrophysics::Galaxy Astrophysics, Physics, [PHYS.PHYS.PHYS-OPTICS]Physics [physics]/Physics [physics]/Optics [physics.optics], Quantum Physics, business.industry, Near-infrared spectroscopy, Laser, 06.20.-f (Metrology), 42.62.Eh (Metrological applications, optical frequency synthesizers for precision spectroscopy), 07.57.Ty (Infrared spectrometers, auxiliary equipment, and technique), Atomic clock, Mode-locking, business, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Quantum Physics (quant-ph), Physics - Optics, Optics (physics.optics)
Abstract

International audience; We present a new method for accurate mid-infrared frequency measurements and stabilization to a near-infrared ultra-stable frequency reference, transmitted with a long-distance fibre link and continuously monitored against state-of-the-art atomic fountain clocks. As a first application, we measure the frequency of an OsO4 rovibrational molecular line around 10 µm with a state-of-the-art uncertainty of 8x10-13. We also demonstrate the frequency stabilization of a mid-infrared laser with fractional stability better than 4x10-14 at 1 s averaging time and a line-width below 17 Hz. This new stabilization scheme gives us the ability to transfer frequency stability in the range of 10-15 or even better, currently accessible in the near-infrared or in the visible, to mid-infrared lasers in a wide frequency range.

Published
2013
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121. Ultra-stable Long Distance Optical Frequency/Time Distribution Using the Internet Network

Author

Giorgio Santarelli, Olivier Lopez, Paul-Eric POTTIE, Rovera, Giovanni D., Joseph Achkar, Anne Amy, Christian Chardonnet, Santarelli, Giorgio, lp2n-06,lp2n-14, Laboratoire Photonique, Numérique et Nanosciences (LP2N), Université Sciences et Technologies - Bordeaux 1-Institut d'Optique Graduate School (IOGS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Institut d'Optique Graduate School (IOGS)-Centre National de la Recherche Scientifique (CNRS), MMTF, Laboratoire de Physique des Lasers (LPL), Université Paris 13 (UP13)-Centre National de la Recherche Scientifique (CNRS)-Université Paris 13 (UP13)-Centre National de la Recherche Scientifique (CNRS), Systèmes de Référence Temps Espace (SYRTE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Université Paris 13 (UP13)-Centre National de la Recherche Scientifique (CNRS), and Université Sciences et Technologies - Bordeaux 1 (UB)-Institut d'Optique Graduate School (IOGS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1 (UB)-Institut d'Optique Graduate School (IOGS)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[PHYS.QPHY]Physics [physics]/Quantum Physics [quant-ph], ComputingMilieux_MISCELLANEOUS, [PHYS.QPHY] Physics [physics]/Quantum Physics [quant-ph]
Abstract

International audience

Published
2013

122. Simultaneous remote transfer of accurate timing and optical frequency over a public fiber network

Author

Anne Amy-Klein, Christian Chardonnet, Paul-Eric Pottie, Daniele Rovera, Amale Kanj, Joseph Achkar, Giorgio Santarelli, Olivier Lopez, MMTF, Laboratoire de Physique des Lasers (LPL), Université Paris 13 (UP13)-Centre National de la Recherche Scientifique (CNRS)-Université Paris 13 (UP13)-Centre National de la Recherche Scientifique (CNRS), Laboratoire national de métrologie et d'essais - Systèmes de Référence Temps-Espace (LNE - SYRTE), Systèmes de Référence Temps Espace (SYRTE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Université Paris 13 (UP13)-Centre National de la Recherche Scientifique (CNRS), lp2n-06,lp2n-14, Laboratoire Photonique, Numérique et Nanosciences (LP2N), Université Sciences et Technologies - Bordeaux 1-Institut d'Optique Graduate School (IOGS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Institut d'Optique Graduate School (IOGS)-Centre National de la Recherche Scientifique (CNRS), ANR BLANC 2011-BS04-009-01, Université Sciences et Technologies - Bordeaux 1 (UB)-Institut d'Optique Graduate School (IOGS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1 (UB)-Institut d'Optique Graduate School (IOGS)-Centre National de la Recherche Scientifique (CNRS), Université Paris 13 (UP13)-Centre National de la Recherche Scientifique (CNRS)-Université Sorbonne Paris Nord, Références micro-ondes et échelles de temps, Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Optical fiber, Physics - Instrumentation and Detectors, Physics and Astronomy (miscellaneous), Computer science, Optical link, General Physics and Astronomy, FOS: Physical sciences, Satellite system, Physics and Astronomy(all), Optical time-domain reflectometer, 01 natural sciences, law.invention, time transfer, 010309 optics, [PHYS.QPHY]Physics [physics]/Quantum Physics [quant-ph], law, Optical Carrier transmission rates, 0103 physical sciences, Fiber optic splitter, Electronic engineering, Time transfer, 010306 general physics, frequency transfer, Quantum Physics, [PHYS.PHYS.PHYS-OPTICS]Physics [physics]/Physics [physics]/Optics [physics.optics], Multi-mode optical fiber, Optical cross-connect, General Engineering, time and frequency metrology, Instrumentation and Detectors (physics.ins-det), (120.3930) Metrological instrumentation, (060.2360) Fiber optics links and subsystems, (120.5050) Phase measurement, Fiber-optic communication, Spread spectrum, Fiber optic sensor, Geostationary orbit, optical link, Timestamp, Quantum Physics (quant-ph), [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Phase modulation, Physics - Optics, Optics (physics.optics)
Abstract

In this work we demonstrate for the first time that it is possible to transfer simultaneously an ultra-stable optical frequency and a precise and accurate timing over 540 km using a public telecommunication optical fiber networks with Internet data. The optical phase is used to carry both the frequency information and the timestamps by modulating a very narrow optical carrier at 1.55 $\mu$m with spread spectrum signals using two-way satellite time transfer modems. The results in term of absolute time accuracy (250 ps) and long-term timing stability (20 ps) well outperform the conventional Global Navigation Satellite System or geostationary transfer methods.

Published
2013
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123. Ultra-stable long distance optical frequency distribution using the Internet fiber network

Author

Olivier Lopez, Christian Chardonnet, A. Haboucha, Bruno Chanteau, Giorgio Santarelli, Anne Amy-Klein, MMTF, Laboratoire de Physique des Lasers (LPL), Université Paris 13 (UP13)-Centre National de la Recherche Scientifique (CNRS)-Université Paris 13 (UP13)-Centre National de la Recherche Scientifique (CNRS), Systèmes de Référence Temps Espace (SYRTE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), lp2n-06,lp2n-14, Laboratoire Photonique, Numérique et Nanosciences (LP2N), Université Sciences et Technologies - Bordeaux 1-Institut d'Optique Graduate School (IOGS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Institut d'Optique Graduate School (IOGS)-Centre National de la Recherche Scientifique (CNRS), ANR BLANC 2011-BS04-009-01 et Université Paris 13 et IFRAF-Conseil Régional Ile-de-France, and Université Sciences et Technologies - Bordeaux 1 (UB)-Institut d'Optique Graduate School (IOGS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1 (UB)-Institut d'Optique Graduate School (IOGS)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Optical link, Beat (acoustics), FOS: Physical sciences, Metrological instrumentation, (120.3930) (060.2360) (140.0140) (120.5050), 01 natural sciences, Lasers and laser optics, law.invention, 010309 optics, Optics, [PHYS.QPHY]Physics [physics]/Quantum Physics [quant-ph], Robustness (computer science), law, 0103 physical sciences, 010306 general physics, Optical Fibers, Physics, Internet, Quantum Physics, [PHYS.PHYS.PHYS-OPTICS]Physics [physics]/Physics [physics]/Optics [physics.optics], Laser diode, business.industry, Bandwidth (signal processing), Equipment Design, Phase measurement, Polarization (waves), Atomic and Molecular Physics, and Optics, Equipment Failure Analysis, Amplitude, The Internet, Fiber optics links and subsystems, Lasers, Semiconductor, business, Quantum Physics (quant-ph), Optics (physics.optics), Physics - Optics
Abstract

International audience; We report an optical link of 540 km for ultrastable frequency distribution over the Internet fiber network. The stable frequency optical signal is processed enabling uninterrupted propagation on both directions. The robustness and the performance of the link are enhanced by a cost effective fully automated optoelectronic station. This device is able to coherently regenerate the return optical signal with a heterodyne optical phase locking of a low noise laser diode. Moreover the incoming signal polarization variation are tracked and processed in order to maintain beat note amplitudes within the operation range. Stable fibered optical interferometer enables optical detection of the link round trip phase signal. The phase-noise compensated link shows a fractional frequency instability in 10 Hz bandwidth of 5x10-15 at one second measurement time and 2x10-19 at 30 000 s. This work is a significant step towards a sustainable wide area ultrastable optical frequency distribution and comparison network.

Published
2012

124. A simplified model for studying bivariate mortality under right-censoring

Author

Philippe Saint-Pierre, Olivier Lopez, Svetlana Gribkova, Laboratoire de Statistique Théorique et Appliquée (LSTA), Université Pierre et Marie Curie - Paris 6 (UPMC), and Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Statistics and Probability, Statistics::Theory, mortality analysis, Bivariate analysis, 01 natural sciences, Copula (probability theory), 010104 statistics & probability, [MATH.MATH-ST]Mathematics [math]/Statistics [math.ST], 0502 economics and business, Statistics, Econometrics, Statistics::Methodology, 0101 mathematics, bivariate censoring, bootstrap, Kaplan–Meier estimator, Survival analysis, 050205 econometrics, Mathematics, Numerical Analysis, Nonparametric estimator, Age differences, Kaplan-Meier estimator, 05 social sciences, Estimator, copula models, nonparametric estimation, [STAT.TH]Statistics [stat]/Statistics Theory [stat.TH], Censoring (statistics), Statistics, Probability and Uncertainty
Abstract

In this paper, we provide a nonparametric estimator of the distribution of bivariate censored lifetimes, in a model where the two censoring variables differ only through an additional observed variable. This situation is motivated by a particular application to insurance, where the supplementary variable corresponds to the age difference between two individuals. Asymptotic results for our estimator are provided. The new tools that we develop are used to perform goodness-of-fit tests for survival copula models. The practical performance is illustrated through simulations and a real data analysis.

Published
2012

125. A proportional hazards regression model with change-points in the baseline function

Author

Olivier Lopez and Abdullah Oueslati

Subjects
Likelihood Functions, Models, Statistical, Proportional hazards model, Applied Mathematics, Regression analysis, General Medicine, Statistics, Covariate, Jump, Piecewise, Humans, Regression Analysis, Life Tables, Semiparametric regression, Log-linear model, Regression diagnostic, Railroads, Algorithms, Mathematics, Proportional Hazards Models
Abstract

In this article, we consider a new regression model for counting processes under a proportional hazards assumption. This model is motivated by the need of understanding the evolution of the booking process of a railway company. The main novelty of the approach consists in assuming that the baseline hazard function is piecewise constant, with unknown times of jump (these times of jump are estimated from the data as model parameters). Hence, the parameters of the model can be separated into two different types: parameters that measure the influence of the covariates, and parameters from a multiple change-point model for the baseline. Cox’s semiparametric regression can be seen as a limit case of our model. We develop an iterative procedure to estimate the different parameters, and a test procedure that allows to perform change-point detection in the baseline. Our technique is supported by simulation studies and a real data analysis, which show that our model can be a reasonable alternative to Cox’s regression model, particularly in the presence of tied event times.

Published
2012

126. Mid-IR frequency measurement using an optical frequency comb and a long-distance remote frequency reference

Author

Wei Zhang, C. Chardonnet, Benoît Darquié, Bruno Chanteau, Giorgio Santarelli, Anne Amy-Klein, F. Auguste, Y. Le Coq, Olivier Lopez, MMTF, Laboratoire de Physique des Lasers (LPL), Université Paris 13 (UP13)-Centre National de la Recherche Scientifique (CNRS)-Université Paris 13 (UP13)-Centre National de la Recherche Scientifique (CNRS), Systèmes de Référence Temps Espace (SYRTE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), lp2n-06,lp2n-14, Laboratoire Photonique, Numérique et Nanosciences (LP2N), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut d'Optique Graduate School (IOGS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1 (UB)-Institut d'Optique Graduate School (IOGS)-Centre National de la Recherche Scientifique (CNRS), Université Paris 13 (UP13)-Centre National de la Recherche Scientifique (CNRS), Métrologie des fréquences optiques, Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), and Université Sciences et Technologies - Bordeaux 1-Institut d'Optique Graduate School (IOGS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Institut d'Optique Graduate School (IOGS)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Materials science, Atomic Physics (physics.atom-ph), Terahertz radiation, Optical link, Measure (physics), FOS: Physical sciences, 02 engineering and technology, 01 natural sciences, Signal, Physics - Atomic Physics, law.invention, 010309 optics, Frequency comb, 020210 optoelectronics & photonics, Optics, [PHYS.QPHY]Physics [physics]/Quantum Physics [quant-ph], law, 0103 physical sciences, 0202 electrical engineering, electronic engineering, information engineering, Quantum, Quantum Physics, [PHYS.PHYS.PHYS-OPTICS]Physics [physics]/Physics [physics]/Optics [physics.optics], business.industry, Laser, Cascade, Quantum Physics (quant-ph), business, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Optics (physics.optics), Physics - Optics
Abstract

International audience; We have built a frequency chain which enables to measure the absolute frequency of a laser emitting in the 28-31 THz frequency range and stabilized onto a molecular absorption line. The set-up uses an optical frequency comb and an ultrastable 1.55 µm frequency reference signal, transferred from LNE-SYRTE to LPL through an optical link. We are now progressing towards the stabilization of the mid-IR laser via the frequency comb and the extension of this technique to quantum cascade lasers. Such a development is very challenging for ultrahigh resolution molecular spectroscopy and fundamental tests of physics with molecules.

Published
2012

127. Progress on an optical link for ultra-stable frequency dissemination using a public telecommunication network

Author

Anne Amy-Klein, Bruno Chanteau, Ch. Chardonnet, Olivier Lopez, Vincent Roncin, A. Haboucha, and Giorgio Santarelli

Subjects
Optical Transport Network, business.industry, Computer science, Optical link, Optical cross-connect, Wavelength-division multiplexing, Fiber optic splitter, Electronic engineering, Optical performance monitoring, Telecommunications, business, Optical add-drop multiplexer, Passive optical network
Abstract

We transfer the frequency of an ultra-stable laser over a 470-km optical link comprising 400 km of public telecommunication fiber network, simultaneously carrying data traffic. A dense wavelength division multiplexing scheme is used. The ultrastable signal is inserted in and extracted from the communication network using bidirectional optical add-drop multiplexers. The link passes through two important nodes of the telecommunication network and an amplification stage. The phase noise on the optical link is compensated with the usual round-trip technique. The 470-km multiplexed link shows an Allan deviation of 5×10×15 at one second and 1.3×10×18 after 1 hour. This work paves the way to a wide dissemination of ultra stable optical clock signals between distant laboratories via the Internet network.

Published
2011
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128. Bivariate censored regression relying on a new estimator of the joint distribution function

Author

Philippe Saint-Pierre, Olivier Lopez, Laboratoire de Statistique Théorique et Appliquée (LSTA), Université Pierre et Marie Curie - Paris 6 (UPMC), and Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Statistics and Probability, Bivariate censoring, Statistics::Theory, 0211 other engineering and technologies, 02 engineering and technology, Bivariate analysis, Statistics::Other Statistics, 01 natural sciences, Copula (probability theory), 010104 statistics & probability, [MATH.MATH-ST]Mathematics [math]/Statistics [math.ST], Regression modeling, Econometrics, Statistics::Methodology, Joint distribution function, 0101 mathematics, Kaplan–Meier estimator, $M-$estimation, Mathematics, Censored regression model, 021103 operations research, Kaplan-Meier estimator, Applied Mathematics, Estimator, i.i.d. representations, Regression analysis, [STAT.TH]Statistics [stat]/Statistics Theory [stat.TH], Statistics::Computation, Censoring (clinical trials), Statistics, Probability and Uncertainty, Copula functions
Abstract

In this paper we study a class of M-estimators in a regression model under bivariate random censoring and provide a set of sufficient conditions that ensure asymptotic n 1 / 2 - convergence . The cornerstone of our approach is a new estimator of the joint distribution function of the censored lifetimes. A copula approach is used to modelize the dependence structure between the bivariate censoring times. The resulting estimators present the advantage of being easily computable. A simulation study enlighten the finite sample behavior of this technique.

Published
2011

129. Cascaded multiplexed optical link on a telecommunication network for frequency dissemination

Author

A. Haboucha, Anne Amy-Klein, Christian Chardonnet, Haifeng Jiang, Georgio Santarelli, Olivier Lopez, Vincent Roncin, Fabien Kéfélian, Bruno Chanteau, Laboratoire de Physique des Lasers (LPL), Université Paris 13 (UP13)-Centre National de la Recherche Scientifique (CNRS), Systèmes de Référence Temps Espace (SYRTE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), ANR Alpha+, LNE, Université Paris 13, and ANR-06-BLAN-0143,ALPHA+,Test de stabilité des constantes fondamentales par conparaisons à longue distance d'horloges optiques ultra-stables(2006)

Subjects
Physics - Instrumentation and Detectors, Computer science, Optical link, (120.3930) , (060.2360) , (140.0140) , (120.5050), FOS: Physical sciences, Metrological instrumentation, 01 natural sciences, Signal, Multiplexing, Multiplexer, Lasers and laser optics, 010309 optics, Computer Communication Networks, Phase measurement, [PHYS.QPHY]Physics [physics]/Quantum Physics [quant-ph], Wavelength-division multiplexing, 0103 physical sciences, Fiber Optic Technology, Fiber, 010306 general physics, Optical Fibers, Repeater, [PHYS.PHYS.PHYS-OPTICS]Physics [physics]/Physics [physics]/Optics [physics.optics], Quantum Physics, Internet, business.industry, Electrical engineering, Signal Processing, Computer-Assisted, Instrumentation and Detectors (physics.ins-det), Equipment Design, Telecommunications network, Atomic and Molecular Physics, and Optics, [SPI.OPTI]Engineering Sciences [physics]/Optics / Photonic, The Internet, Fiber optics links and subsystems, business, Quantum Physics (quant-ph), Physics - Optics, Optics (physics.optics)
Abstract

International audience; We demonstrate a cascaded optical link for ultrastable frequency dissemination comprised of two compensated links of 150 km and a repeater station. Each link includes 114 km of Internet fiber simultaneously carrying data traffic through a dense wavelength division multiplexing technology, and passes through two routing centers of the telecommunication network. The optical reference signal is inserted in and extracted from the communication network using bidirectional optical add-drop multiplexers. The repeater station operates autonomously ensuring noise compensation on the two links and the ultra-stable signal optical regeneration. The compensated link shows a fractional frequency instability of 3×10-15 at one second measurement time and 5×10-20 at 20 hours. This work paves the way to a wide dissemination of ultra-stable optical clock signals between distant laboratories via the Internet network.

Published
2010

130. Alpha-particle condensation in excited 12C

Author

Raduta, Ad R., Borderie, B., Geraci, E., Neindre, N. Le, Napolitani, P., Rivet, M. F., Alba, R., Amorini, F., Cardella, G., Chatterjee, M., Filippo, E., Guinet, D., Lautesse, P., La Guidara, E., Lanzalone, G., Lanzano, G., Lombardo, I., Olivier Lopez, Maiolino, C., Pagano, A., Pirrone, S., Politi, G., Porto, F., Rizzo, F., Russotto, P., Wieleczko, J. P., Institut de Physique Nucléaire d'Orsay (IPNO), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Institut de Physique Nucléaire de Lyon (IPNL), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Laboratoire de physique corpusculaire de Caen (LPCC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Grand Accélérateur National d'Ions Lourds (GANIL), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Normandie Université (NU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Nuclear Theory, FOS: Physical sciences, Nuclear Experiment (nucl-ex), [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Nuclear Experiment
Abstract

The fragmentation of quasi-projectiles from the nuclear reaction $^{40}Ca$+$^{12}C$ at 25 MeV/nucleon was used to produce excited states candidates to $\alpha$-particle condensation. The methodology relies on high granularity 4$\pi$ detection coupled to correlation function techniques. Under the assumption that the equality among the kinetic energies of the emitted $\alpha$-particles and the emission simultaneity constitutes a reliable fingerprint of $\alpha$ condensation, we identify several tens of events corresponding to the deexcitation of the Hoyle state of $^{12}$C which fulfill the condition., Comment: 5 pages, 3 figures

Published
2010

131. Multiplexed optical link for ultra-stable frequency dissemination

Author

Fabien Kéfélian, C. Chardonnet, H. Jiang, A. Haboucha, B. Chanteau, Anne Amy-Klein, Giorgio Santarelli, Olivier Lopez, and Vincent Roncin

Subjects
Repeater, Optical amplifier, Computer science, Optical link, Wavelength-division multiplexing, Phase noise, Electronic engineering, Multiplexing, Multiplexer, Telecommunications network
Abstract

We transfer the frequency of an ultra-stable laser over a cascaded optical link comprising two compensated links of 150 km and a repeater station. Each link passes through two important nodes of the telecommunication network and includes 114 km of Internet fiber simultaneously carrying data traffic, through a dense wavelength division multiplexing scheme. The metrological signal is inserted in and extracted from the communication network using bidirectional optical add-drop multiplexers. The repeater station is working independently without any remote control. The phase noise on the two links is compensated with the usual round-trip technique. The 300-km multiplexed cascaded link shows an Allan deviation of 3×10−15 at one second and 7×10−20 at 20 hours. This work paves the way to a wide dissemination of ultra stable optical clock signals between distant laboratories via the Internet network.

Published
2010
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132. STABILITY OF THE PROTON-TO-ELECTRON MASS RATIO TESTED WITH MOLECULES USING AN OPTICAL LINK TO PRIMARY CLOCK

Author

Christophe Daussy, Andrei Goncharov, Giorgio Santarelli, Olivier Lopez, Anne Amy-Klein, H. Jiang, Fabien Kéfélian, R.J. Butcher, C. Chardonnet, and A. Shelkovnikov

Subjects
Time delay and integration, Optics, Chemistry, business.industry, Primary standard, Wavelength-division multiplexing, Optical link, Resolution (electron density), Rotational–vibrational spectroscopy, Proton-to-electron mass ratio, business, Signal
Abstract

of a rovibrational transition in SF6 with the fundamental hyperfine transition in Cs. This result is direct and model-free. As far as we know, it is the most precise absolute frequency measurement of a molecular transition. It was performed using an optical link to transfer the primary standard frequency controlled with a Cs fountain from LNESYRTE to LPL. Last developments on that optical link show a resolution of a few 10 at 1 s integration time and around 10 at 1 day. This resolution is preserved when a nondedicated fiber is used. In that case, the metrological signal is transferred together with the digital data signal from the Internet traffic using two different frequency channels in a dense wavelength division multiplexing scheme.

Published
2010
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133. Determination of the Boltzmann constant by laser spectroscopy as a basis for future measurements of the thermodynamic temperature

Author

Christophe Daussy, Olivier Lopez, S. Briaudeau, Christian J. Bordé, Benoît Darquié, Christian Chardonnet, Anne Amy-Klein, Cyril Lemarchand, Khelifa Djerroud, Laboratoire de Physique des Lasers (LPL), Université Paris 13 (UP13)-Centre National de la Recherche Scientifique (CNRS), Laboratoire commun de métrologie LNE-CNAM (LCM), Laboratoire National de Métrologie et d'Essais [Trappes] (LNE )-Conservatoire National des Arts et Métiers [CNAM] (CNAM), LNE + EraNet/IMERA, and Optical measurement of kB

Subjects
Atomic Physics (physics.atom-ph), FOS: Physical sciences, fundamental constants, 01 natural sciences, absorption line shape, law.invention, Physics - Atomic Physics, 010309 optics, symbols.namesake, [PHYS.QPHY]Physics [physics]/Quantum Physics [quant-ph], law, 0103 physical sciences, Thermal, Homogeneity (physics), 010306 general physics, Spectroscopy, thermodynamic temperature, Physics, Quantum Physics, Absorption cell, Thermodynamic temperature, Condensed Matter Physics, Thermostat, Boltzmann constant, laser spectroscopy, symbols, Atomic physics, Quantum Physics (quant-ph), Doppler effect
Abstract

International audience; In this paper, we present the latest results on the measurement of the Boltzmann constant kB , by laser spectroscopy of ammonia at 10 μm. The Doppler absorption profile of a ro-vibrational line of an NH3 gas sample at thermal and pressure equilibrium is measured as accurately as possible. The absorption cell is placed inside a large 1m3 thermostat filled with an ice-water mixture, which sets the temperature very close to 273.15 K. Analysing this profile, which is related to the Maxwell-Boltzmann molecular speed distribution, leads to a determination of the Boltzmann constant via a measurement of the Doppler width (proportional tosqrt( kBT) ). A spectroscopic determination of the Boltzmann constant with an uncertainty as low as 37 ppm is obtained. Recent improvements with a new passive thermostat lead to a temperature accuracy, stability and homogeneity of the absorption cell better than 1 ppm over a day.

Published
2009
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134. Long-distance ultrastable frequency transfer over urban fiber link: toward a European network

Author

Anne Amy-Klein, Christian Chardonnet, Fabien Kéfélian, Haifeng Jiang, Olivier Lopez, and Giorgio Santarelli

Subjects
Optical fiber, business.product_category, business.industry, Computer science, Electrical engineering, Optical communication, Laser, Signal, Telecommunications network, law.invention, Optics, Transmission (telecommunications), law, Wavelength-division multiplexing, Internet access, Fiber, business
Abstract

Experiments of transmission of sub-Hz cavity-stabilized 1542 nm laser frequency using a pair of 43 km dark fibers in urban environment are reported on successively 86 km and 172 km, with fractional frequency instability in the 10 -19 range. A new approach is then introduced consisting in using part of an optical telecommunications network carrying simultaneously data traffic using a DWDM scheme to multiplex the metrological signal. This method is experimentally implemented using 22 km of fiber linking Universite Paris 13 to its internet access point without degradation of the link instability. We finally present a project of large scale link between Paris and the German border using RENATER network which could constitute the first step of the building of a European optical network for ultrastable frequency dissemination and comparison.

Published
2009
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135. High-resolution optical frequency dissemination on a telecommunication network with data traffic

Author

Olivier Lopez, Fabien Kéfélian, Haifeng Jiang, Anne Amy-Klein, Christian Chardonnet, Georgio Santarelli, Laboratoire de Physique des Lasers (LPL), Université Paris 13 (UP13)-Centre National de la Recherche Scientifique (CNRS), Systèmes de Référence Temps Espace (SYRTE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), ANR Alpha+, Lien optique, and ANR-06-BLAN-0143,ALPHA+,Test de stabilité des constantes fondamentales par conparaisons à longue distance d'horloges optiques ultra-stables(2006)

Subjects
Computer science, Optical communication, FOS: Physical sciences, transfert de fréquence, 01 natural sciences, Signal, Multiplexer, law.invention, 010309 optics, OADM, [PHYS.QPHY]Physics [physics]/Quantum Physics [quant-ph], law, Optical frequencies, Wavelength-division multiplexing, 0103 physical sciences, Phase noise, OCIS 060.2360, 120.3930, Fiber, Allan variance, 010306 general physics, Quantum Physics, business.industry, lien optique, Electrical engineering, Laser, Telecommunications network, Atomic and Molecular Physics, and Optics, Interferometry, réseaux optiques, Quantum Physics (quant-ph), business
Abstract

International audience; We transferred the frequency of an ultra-stable laser over a 108 km urban fiber link comprising 22 km of optical communications network fiber simultaneously carrying Internet data traffic. The metrological signal and the digital data signal are transferred on two different frequency channels in a dense wavelength division multiplexing scheme. The metrological signal is inserted into and extracted from the communications network by using bidirectional off-the-shelf optical add-drop multiplexers. The link-induced phase noise is measured and cancelled with round-trip technique using an all-fiber-based interferometer. The compensated link shows an Allan deviation of a few 10-16 at one second and below 10-19 at 10,000 seconds. This opens the way to a wide dissemination of ultra stable optical clock signals between distant laboratories via the Internet network.

Published
2009

136. OPTICAL FREQUENCY TRANSFER OVER 172 KM OF INSTALLED FIBER

Author

Haifeng Jiang, Olivier Lopez, Fabien Kéfélian, Scott Crane, Giorgio Santarelli, Ch. Chardonnet, Pierre Lemonde, and Anne Amy-Klein

Subjects
Multi-mode optical fiber, Optics, Materials science, Optical frequencies, Fiber optic sensor, business.industry, Dispersion-shifted fiber, Fiber, business, Fiber-optic communication
Published
2009
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137. High-resolution optical frequency dissemination on a telecommunication network

Author

Christian Chardonnet, Olivier Lopez, Haifeng Jiang, Anne Amy-Klein, Giorgio Santarelli, and Fabien Kéfélian

Subjects
Engineering, Optical fiber, business.industry, Multiplexing, Passive optical network, Signal, Telecommunications network, law.invention, Optical Transport Network, law, Wavelength-division multiplexing, Phase noise, Electronic engineering, business
Abstract

We transferred the frequency of an ultrastable laser over a 108-km-long urban fiber link comprising 22 km of an optical communication network fiber simultaneously carrying Internet data traffic. The metrological signal and the digital data signal were transferred over two different frequency channels in a dense wavelength-division multiplexing scheme. The metrological signal was inserted in and extracted from the communication network using bidirectional off-the-shelf optical add-drop multiplexers. The link-induced phase noise was measured and canceled with a round-trip technique using an all-fiber-based interferometer. The compensated link showed an Allan deviation of a few 10−16 at one second and below 10−19 at 10,000 s This work paves the way to a wide dissemination of ultrastable optical clock signals between distant laboratories via the Internet network.

Published
2009
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138. Conditional density estimation in a censored single-index regression model

Author

Olivier Lopez, Olivier Bouaziz, Laboratoire de Statistique Théorique et Appliquée (LSTA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), and Université Pierre et Marie Curie - Paris 6 (UPMC)

Subjects
Statistics and Probability, Statistics::Theory, Single-index model, asymptotic normality, 62N01,62N02, Asymptotic distribution, Mathematics - Statistics Theory, Statistics Theory (math.ST), 01 natural sciences, 010104 statistics & probability, censoring, [MATH.MATH-ST]Mathematics [math]/Statistics [math.ST], single-index model, 0502 economics and business, FOS: Mathematics, Applied mathematics, Statistics::Methodology, 0101 mathematics, 050205 econometrics, Mathematics, martingales for counting processes, empirical processes, 05 social sciences, Estimator, Regression analysis, Conditional probability distribution, [STAT.TH]Statistics [stat]/Statistics Theory [stat.TH], Regression, Censoring (clinical trials), pseudo-maximum likelihood, Smoothing
Abstract

Under a single-index regression assumption, we introduce a new semiparametric procedure to estimate a conditional density of a censored response. The regression model can be seen as a generalization of the Cox regression model and also as a profitable tool for performing dimension reduction under censoring. This technique extends the results of Delecroix et al. [J. Multivariate Anal. 86 (2003) 213–226]. We derive consistency and asymptotic normality of our estimator of the index parameter by proving its asymptotic equivalence with the (uncomputable) maximum likelihood estimator, using martingales results for counting processes and arguments from empirical processes theory. Furthermore, we provide a new adaptive procedure which allows us both to choose the smoothing parameter involved in our approach and to circumvent the weak performances of the Kaplan–Meier estimator [Amer. Statist. Assoc. 53 (1958) 457–481] in the right-tail of the distribution. By means of a simulation study, we study the behavior of our estimator for small samples.

Published
2009

139. High-resolution microwave frequency dissemination on an 86-km urban optical link

Author

Olivier Lopez, M. Lours, Ch. Chardonnet, Anne Amy-Klein, Georgio Santarelli, Laboratoire de Physique des Lasers (LPL), Université Paris 13 (UP13)-Centre National de la Recherche Scientifique (CNRS), Systèmes de Référence Temps Espace (SYRTE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), and Lien optique

Subjects
Time delay and integration, Physics and Astronomy (miscellaneous), Computer science, Optical link, General Engineering, General Physics and Astronomy, High resolution, FOS: Physical sciences, 02 engineering and technology, 021001 nanoscience & nanotechnology, 01 natural sciences, Signal, Stability (probability), Scrambling, Compensation (engineering), 010309 optics, [PHYS.QPHY]Physics [physics]/Quantum Physics [quant-ph], 0103 physical sciences, Phase noise, Electronic engineering, PACS : 42.62.Eh, 06.30.Ft, 42.81.Uv, 0210 nano-technology, Physics - Optics, Optics (physics.optics)
Abstract

We report the first demonstration of a long-distance ultra stable frequency dissemination in the microwave range. A 9.15 GHz signal is transferred through a 86-km urban optical link with a fractional frequency stability of 1.3x10-15 at 1 s integration time and below 10-18 at one day. The optical link phase noise compensation is performed with a round-trip method. To achieve such a result we implement light polarisation scrambling and dispersion compensation. This link outperforms all the previous radiofrequency links and compares well with recently demonstrated full optical links., Comment: 11 pages, 5 figures

Published
2009
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140. On the estimation of the joint distribution in regression models with censored responses

Author

Olivier Lopez, Institut de Recherche Mathématique de Rennes ( IRMAR ), Université de Rennes 1 ( UR1 ), Université de Rennes ( UNIV-RENNES ) -Université de Rennes ( UNIV-RENNES ) -AGROCAMPUS OUEST-École normale supérieure - Rennes ( ENS Rennes ) -Institut National de Recherche en Informatique et en Automatique ( Inria ) -Institut National des Sciences Appliquées ( INSA ) -Université de Rennes 2 ( UR2 ), Université de Rennes ( UNIV-RENNES ) -Centre National de la Recherche Scientifique ( CNRS ), Centre de Recherche en Économie et Statistique ( CREST ), Ecole Nationale de la Statistique et de l'Analyse de l'Information [Bruz] ( ENSAI ) -École polytechnique ( X ) -École Nationale de la Statistique et de l'Administration Économique ( ENSAE ParisTech ), Institut de Recherche Mathématique de Rennes (IRMAR), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-École normale supérieure - Rennes (ENS Rennes)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-INSTITUT AGRO Agrocampus Ouest, Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro), Centre de Recherche en Économie et Statistique (CREST), Ecole Nationale de la Statistique et de l'Analyse de l'Information [Bruz] (ENSAI)-École polytechnique (X)-École Nationale de la Statistique et de l'Administration Économique (ENSAE Paris)-Centre National de la Recherche Scientifique (CNRS), AGROCAMPUS OUEST, Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Université de Rennes 2 (UR2), Université de Rennes (UNIV-RENNES)-École normale supérieure - Rennes (ENS Rennes)-Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), and Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)

Subjects
right censored regression, [MATH.MATH-ST]Mathematics [math]/Statistics [math.ST], asymptotic normality, MSC2000 : 62N01, 62G30, 60F05, law of large numbers, Statistics::Methodology, [STAT.TH]Statistics [stat]/Statistics Theory [stat.TH], kernel estimators, [ MATH.MATH-ST ] Mathematics [math]/Statistics [math.ST], distribution function, [ STAT.TH ] Statistics [stat]/Statistics Theory [stat.TH]
Abstract

In a regression model with univariate censored responses, a new estimator of the joint distribution function of the covariates and response is proposed, under the assumption that the response and the censoring variable are independent conditionally to the covariates. This estimator is an extension of the multivariate empirical function used in the uncensored case. Furthermore, under some simple additional identifiability assumption, this estimator is not sensible to the "curse of dimensionality", so that it allows to infer on models with multidimensional covariates. Integrals with respect to this empirical measure are considered. Consistency and asymptotic normality of these integrals over a class of functions is obtained, by deriving asymptotic i.i.d. representations. Several applications of the new estimator are proposed.

Published
2008

141. Nonlinear censored regression using synthetic data

Author

Olivier Lopez, Michel Delecroix, Valentin Patilea, Laboratoire de Statistique Théorique et Appliquée (LSTA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche Mathématique de Rennes (IRMAR), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-École normale supérieure - Rennes (ENS Rennes)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-INSTITUT AGRO Agrocampus Ouest, Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro), Université Pierre et Marie Curie - Paris 6 (UPMC), AGROCAMPUS OUEST, Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Université de Rennes 2 (UR2), Université de Rennes (UNIV-RENNES)-École normale supérieure - Rennes (ENS Rennes)-Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), and Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)

Subjects
Statistics and Probability, asymptotic normality, Kaplan-Meier integral, Asymptotic distribution, 01 natural sciences, Least squares, Synthetic data, 010104 statistics & probability, Consistency (statistics), [MATH.MATH-ST]Mathematics [math]/Statistics [math.ST], 0502 economics and business, Statistics, 0101 mathematics, 050205 econometrics, Mathematics, Censored regression model, consistency, 05 social sciences, 62J02, 62N01, Estimator, Regression analysis, synthetic data, nonlinear regression, right censoring, Statistics, Probability and Uncertainty, Nonlinear regression
Abstract

The problem of estimating a nonlinear regression model when the dependent variableis randomly censored is considered. The parameter of the model is estimated by leastsquares using synthetic data, that is a suitable transformation of the response variablesthat preserves the conditional expectation. Two such transformations are considered.Consistency and asymptotic normality of the least squares estimators are derived. Theproofs are based on a novel approach that uses i.i.d. representation of synthetic datathrough Kaplan-Meier integrals. The asymptotic results are completed by a small com-parative simulation study.

Published
2008
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142. Long-distance frequency transfer over an urban fiber link using optical phase stabilization

Author

Anne Amy-Klein, C. Chardonnet, Pierre Lemonde, Michel Lours, J. Millo, Scott Crane, David Holleville, Olivier Lopez, Haifeng Jiang, Fabien Kéfélian, Georgio Santarelli, Systèmes de Référence Temps Espace (SYRTE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique des Lasers (LPL), Université Paris 13 (UP13)-Centre National de la Recherche Scientifique (CNRS), United States Naval Observatory (USNO), ANR Alpha+, ANR Alpha +, and ANR-06-BLAN-0143,ALPHA+,Test de stabilité des constantes fondamentales par conparaisons à longue distance d'horloges optiques ultra-stables(2006)

Subjects
Materials science, Physics - Instrumentation and Detectors, FOS: Physical sciences, Polarization-maintaining optical fiber, 01 natural sciences, Graded-index fiber, 010309 optics, Laser linewidth, Optics, [PHYS.QPHY]Physics [physics]/Quantum Physics [quant-ph], Fiber laser, Wavelength-division multiplexing, 0103 physical sciences, Dispersion-shifted fiber, Fiber, 010306 general physics, métrologie, 060.2360, 120.3930, Quantum Physics, business.industry, lien optique, Statistical and Nonlinear Physics, Instrumentation and Detectors (physics.ins-det), Atomic and Molecular Physics, and Optics, Fiber optic sensor, dissémination de fréquence, business, Quantum Physics (quant-ph)
Abstract

International audience; We transferred the frequency of an ultra-stable laser over 86 km of urban fiber. The link is composed of two cascaded 43-km fibers connecting two laboratories, LNE-SYRTE and LPL in Paris area. In an effort to realistically demonstrate a link of 172 km without using spooled fiber extensions, we implemented a recirculation loop to double the length of the urban fiber link. The link is fed with a 1542-nm cavity stabilized fiber laser having a sub-Hz linewidth. The fiber-induced phase noise is measured and cancelled with an all fiber-based interferometer using commercial off the shelf pigtailed telecommunication components. The compensated link shows an Allan deviation of a few 10-16 at one second and a few 10-19 at 10,000 seconds.

Published
2008
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143. 86-km optical link with a resolution of 2.10-18 for RF frequency transfer

Author

Anne Amy-Klein, Michel Lours, Olivier Lopez, Christian Chardonnet, F. Narbonneau, Christophe Daussy, Georgio Santarelli, Laboratoire de Physique des Lasers (LPL), Université Paris 13 (UP13)-Centre National de la Recherche Scientifique (CNRS), Systèmes de Référence Temps Espace (SYRTE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), and Université Paris 13 (UP13)-Centre National de la Recherche Scientifique (CNRS)-Université Sorbonne Paris Nord

Subjects
Materials science, Optical link, FOS: Physical sciences, 01 natural sciences, Scrambling, 010309 optics, Optics, [PHYS.QPHY]Physics [physics]/Quantum Physics [quant-ph], 0103 physical sciences, Dispersion (optics), 010306 general physics, Optical amplifier, frequency transfer, Quantum Physics, business.industry, Resolution (electron density), Mode (statistics), Atomic and Molecular Physics, and Optics, metrology, PACS : 42.62.Eh, 06.30.Ft, 42.81.Uv, 42.81.Gs, optical link, Radio frequency, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], business, Quantum Physics (quant-ph), Sensitivity (electronics)
Abstract

International audience; RF frequency transfer over an urban 86 km fibre has been demonstrated with a resolution of 2×10-18 at one day measuring time using an optical compensator. This result is obtained with a reference carrier frequency of 1 GHz, and a rapid scrambling of the polarisation state of the input light in order to reduce the sensitivity to the polarisation mode dispersion in the fibre. The limitation due to the fibre chromatic dispersion associated with the laser frequency fluctuations is highlighted and analyzed. A preliminary test of an extended compensated link over 186 km using optical amplifiers gives a resolution below 10-17 at 1 day.

Published
2008
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144. Synthetic data based nonparametric testing of parametric mean-regression models with censored data

Author

Olivier Lopez, Valentin Patilea, Laboratoire de Statistique Théorique et Appliquée (LSTA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche Mathématique de Rennes (IRMAR), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-École normale supérieure - Rennes (ENS Rennes)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-INSTITUT AGRO Agrocampus Ouest, Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro), Université Pierre et Marie Curie - Paris 6 (UPMC), AGROCAMPUS OUEST, Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Université de Rennes 2 (UR2), Université de Rennes (UNIV-RENNES)-École normale supérieure - Rennes (ENS Rennes)-Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA), and Guillemer, Marie-Annick

Subjects
Statistics::Theory, [STAT.TH] Statistics [stat]/Statistics Theory [stat.TH], Nonparametric statistics, 020206 networking & telecommunications, Regression analysis, 02 engineering and technology, [STAT.TH]Statistics [stat]/Statistics Theory [stat.TH], 01 natural sciences, Censoring (statistics), 62-06, 010104 statistics & probability, [MATH.MATH-ST]Mathematics [math]/Statistics [math.ST], Linear regression, Statistics, 0202 electrical engineering, electronic engineering, information engineering, Test statistic, Kernel smoother, Statistics::Methodology, 0101 mathematics, [MATH.MATH-ST] Mathematics [math]/Statistics [math.ST], ComputingMilieux_MISCELLANEOUS, Quantile, Parametric statistics, Mathematics
Abstract

We develop a kernel smoothing based test of a parametric mean-regression model against a nonparametric alternative when the response variable is rightcensored. The new test statistic is inspired by the synthetic data approach for estimating the parameters of a (non)linear regression model under censoring. The asymptotic critical values of our tests are given by the quantiles of the standard normal law. The test is consistent against any fixed alternative, against local Pitman alternatives and uniformly over alternatives in Holder classes of functions of known regularity.

Published
2007

145. Nonparametric Lack-of-fit Tests for Parametric Mean-Regression Model with Censored Data

Author

Olivier Lopez and Valentin Patilea

Subjects
Statistics::Theory
Abstract

We develop two kernel smoothing based tests of a parametric mean-regressionmodel against a nonparametric alternative when the response variable is right-censored. The new test statistics are inspired by the synthetic data and the weightedleast squares approaches for estimating the parameters of a (non)linear regressionmodel under censoring. The asymptotic critical values of our tests are given by thequantiles of the standard normal law. The tests are consistent against ¯xed alter-natives, local Pitman alternatives and uniformly over alternatives in HÄolder classesof functions of known regularity.

Published
2007

146. Frequency dissemination with a 86-km optical fibre for fundamental tests of physics

Author

Anne Amy-Klein, C. Chardonnet, Olivier Lopez, Giorgio Santarelli, Christophe Daussy, Laboratoire de Physique des Lasers (LPL), Université Paris 13 (UP13)-Centre National de la Recherche Scientifique (CNRS)-Université Sorbonne Paris Nord, Systèmes de Référence Temps Espace (SYRTE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Métrologie des fréquences optiques, Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, Optical fiber, business.industry, Optical link, Resolution (electron density), General Physics and Astronomy, Electron, Propagation delay, Stability (probability), law.invention, Optics, law, Phase noise, business, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Line (formation)
Abstract

International audience; A 43-km optical link has been developed between LPL and LNE-SYRTE, to transfer a primary reference frequency in the RF or microwave range. The phase noise introduced by the fluctuations of the propagation delay is compensated using a delay line. The resolution has been improved by increasing the transferred frequency up to 9 GHz. This link was used to compare a molecular optical clock in LPL to a primary reference in SYRTE, which leads to a test of the stability of electron to proton mass ratio.

Published
2007
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147. Absolute frequency measurements for hyperfine structure determination of the R(26) 62-0 transition at 501.7 nm in molecular iodine

Author

Andrei Goncharov, Frédéric Du Burck, Anne Amy-Klein, Olivier Lopez, Institute of Laser Physics of SB RAS (ILP), Siberian Branch of the Russian Academy of Sciences (SB RAS), Laboratoire de Physique des Lasers (LPL), and Centre National de la Recherche Scientifique (CNRS)-Université Sorbonne Paris Nord

Subjects
Materials science, Atomic Physics (physics.atom-ph), Absolute frequency, iodine spectroscopy, FOS: Physical sciences, chemistry.chemical_element, Comb generator, 02 engineering and technology, Iodine, 01 natural sciences, law.invention, Physics - Atomic Physics, 010309 optics, Laser linewidth, 06.20.-f, 06.20.F, 06.30.Bp, 06.30.Ft, 33.20.-t, optical frequency measurement, [PHYS.QPHY]Physics [physics]/Quantum Physics [quant-ph], law, 0103 physical sciences, 0202 electrical engineering, electronic engineering, information engineering, Hyperfine structure, femtosecond comb, [PHYS.PHYS.PHYS-ATOM-PH]Physics [physics]/Physics [physics]/Atomic Physics [physics.atom-ph], 020208 electrical & electronic engineering, General Engineering, Laser, hyperfine interaction, chemistry, Femtosecond, Atomic physics, Laser frequency
Abstract

International audience; The absolute frequencies of the hyperfine components of the R(26) 62-0 transition in molecular iodine at 501.7 nm are measured for the first time with an optical clockwork based on a femtosecond laser frequency comb generator. The set-up is composed of an Ar+ laser locked to a hyperfine component of the R(26) 62-0 transition detected in a continuously pumped low-pressure cell (0.33 Pa). The detected resonances show a linewidth of 45 kHz (half-width at half-maximum). The uncertainty of the frequency measurement is estimated to be 250 Hz.

Published
2007

149. Fiber frequency dissemination with resolution in the 10¿18 range

Author

Michel Lours, F. Narbonneau, Ch. Chardonnet, Giorgio Santarelli, Christophe Daussy, Olivier Lopez, and Anne Amy-Klein

Subjects
Engineering, Optical fiber, business.industry, Resolution (electron density), Signal, Telecommunications network, Stability (probability), law.invention, Compensation (engineering), Optics, law, Range (statistics), Fiber, business
Abstract

The paper presents an ultra-stable fibre optic link which allows to transfer frequency reference signal between two research laboratories. The link is composed of two 43 km twin optical fibres of the Paris telecommunications network that rely the LPL to LNE-SYRTE. The stability of the transferred signal is degraded by mechanical vibration and temperature variation along the fibre. To correct these effects a compensation system has been developed who acts directly on the fibre length, with a variable optical delay line

Published
2006
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150. Calcite surface renewal caused by fluid inclusions mobility: An AFM study

Author

Pierpaolo Zuddas, Olivier Lopez, Dynamique et thermodynamique nucléaire, Institut de Physique du Globe de Paris (IPGP), and Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-IPG PARIS-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-IPG PARIS-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Calcite, Surface (mathematics), 010504 meteorology & atmospheric sciences, Atomic force microscopy, Geochemistry, Mineralogy, 010502 geochemistry & geophysics, 01 natural sciences, chemistry.chemical_compound, chemistry, Geochemistry and Petrology, Fluid inclusions, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, Geology, 0105 earth and related environmental sciences
Published
2006
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