Search results for " Communication"

Optical Cavity-Less 40-GHz Picosecond Pulse Generator in the Visible Wavelength Range

2019

International audience; High-repetition-rate optical frequency-comb sources emitting picosecond pulses play important roles in variousscientific researches and industrial applications. Such ultrafast pulse sources are mostly generated in opticalcavities or microresonators. By means of the wavelength-conversion techniques, it is possible to transfer thecavity-based near-IR robust and compact sources to the mid-IR or to the visible wavelength regions [1-2], forwhich there is an increasing demand, for biophotonics and other applications. Here we demonstrate the generationof high-repetition-rate picosecond pulses in the visible wavelength range by using a fully optical cavity-lessconfiguration.…

All-optical measurement of residual chromatic dispersion and OSNR using self-phase modulation in optical fiber

2011

International audience; We describe a new all-fibered device providing high accuracy all-optical measurements of both optical signal to noise ratio and residual chromatic dispersion. Taking advantage of the self-phase modulation driven spectral evolution of pulses propagating in a highly non-linear medium, we have numerically and experimentally validated the benefits of using an anomalous dispersive fiber combined with a central spectral filtering.

Generalisation and experimental validation of design rules for self-phase modulation-based 2R regenerators

2007

We report the design of 2R-regenerators based on self-phase modulation in lossy fibers. We experimentally demonstrate the applicability of the proposed scaling rules and present detailed characterization of the pulse characteristics at the regenerator output.

Chapter 16 : INDEED, high bit-rate infrared communications

2002

Observation of light-by-light polarization control and stabilization in optical fibre for telecommunication applications

2010

International audience; In many photonics applications, especially in optical fibre based systems, the state of polarization of light remains so far an elusive uncontrolled variable, which can dramatically affect the performances of that systems and which one would like to control as finely as possible. Here, we experimentally demonstrate light-by-light polarization control via a nonlinear effect occurring in single mode optical fibre. We observe a polarization attraction and stabilization of a 10 Gbit/s optical telecommunication signal around 1550 nm. We also validate the potentiality of the device to annihilate very fast nanosecond polarization bursts. This result confirms yet another fas…

On recent progress in all-fibered pulsed optical sources from 20 GHz to 2 THz based on multiple four wave mixing approach

2009

International audience; In this paper, we report recent progress on the design of all-fibered ultra-high repetition-rate pulse sources for telecommunication applications around 1550 nm. Based on the nonlinear compression of an initial beat-signal in optical fibers through a multiple four-wave mixing process, we theoretically and experimentally demonstrate that this simple technique allows an efficient and accurate design of versatile pulse sources having repetition rates and pulse durations ranging from 20 GHz up to 2 THz and from 10 ps up to 110 fs, respectively.

Measuring ‘indirect’ investments in ICT in OECD countries

2019

International audience; ICT components, such as microprocessors, may be embodied in other capital goods not recorded as ICT in National Accounts. We name ‘indirect ICT investment’ the value of embodied ICT components in non-ICT investment. The paper provides estimates of ‘indirect ICT investment’ based on detailed and unpublished Supply-Use tables (SUT) in 12 OECD countries: Australia, Belgium, Canada, Chile, Czech Republic, Denmark, France, Germany, Japan, Israel, Mexico, New Zealand, the United Kingdom, and the United States.Our main finding is that ICT investment appears significantly higher when considering its indirect component, the average increase being about 35%. The inclusion of i…

Les agriculteurs rémunérés pour services rendus à l’environnement ?

2020

International audience; Dans sa proposition de réforme de la Pac, la Commission européenne proposait, fin 2017, de remplacer les mesures environnementales par des PSE (paiements pour services environnementaux). Ce chantier est plus ou moins avancé selon les services

Pesticides : la France peut-elle en sortir ?

2020

International audience; Au lieu de baisser, la consommation de pesticides ne fait quegrimper en France. Comment l'expliquer ? Et peut-on encorecroire au plan Ecophyto ? Science & Vie a posé la question auspécialiste de l'agroécologie Xavier Reboud (INRAE).Les résultats du plan gouvernemental Ecophyto, visant à réduire l’utilisation desproduits phytosanitaires dans l’agriculture, sont tombés il y a quelques jours. Et ilssont désespérants : entre 2017 et 2018, les quantités de substances activesvendues se sont envolées de 21% (dont +11% pour le glyphosate). Soit une haussede 22 % entre la période 2009-2011 et 2016-2018, alors que le programmeEcophyto vise tout au contraire une réduction des u…

Décryper les micro-organismes des sols

2018

National audience; Lionel Ranjard, écologue microbien à l’Inra de Dijon, est intervenu devant les adhérents de l’UCPT pour leur présenter 10 ans d’analyse microbiologique des sols français. Les micro-organismes sont à mettre en lien avec la fertilité et la productivité des sols.« Un diagnostic détaillé de nos sols peut nous permettre de faire évoluer nos pratiques afin de gagner en fertilité et en productivité sur le long terme. Nous connaissons ce qui est du domaine du visible, comme l’importance des vers de terre, mais l’invisible a un rôle primordial dans la vie du sol et on ne peut pas l’identifier à l’oeil », déclare Jean-Jacques Le Bris, vice-président de l’Union des coopératives de P…