Commissariat &#xc0; L'&#xc9;nergie Atomique Et Aux &#xc9;nergies Alternatives

Centre National De La Recherche Scientifique

Safran

Université Grenoble Alpes

Institut Polytechnique De Grenoble

Commissariat a L'energie Atomique

Cnrs

Université De Lille

Guillaume Laffont

Jean-Guillaume Coutard

Alain Gliere

Skandar Basrour

Thomas Lauwers

Pierre Labeye

Pierre Ferdinand

Sylvain Magne

Christian Bolzmacher

Bastien Jacques Chapuis

Stéphane Rougeault

Romain Coulon

Laurent Maurin

Patrick Bulot

Odile Cristini

Monika Bouet

Marc Douay

Remy Bernard

Rudy Desmarchelier

Nicolas Roussel

Romain Cotillard

Jonathan Dumazert

The invention relates to a device and method for detecting an acoustic wave propagating toward a membrane, the membrane carrying a waveguide comprising an optical cavity defining a resonant frequency. Under the effect of a vibration of the membrane, the resonance frequency of the optical cavity varies. The device includes a light source for directing a light wave into the optical cavity, and a servo circuit for servo-controlling the wavelength of the light wave to the resonant wavelength of the optical cavity. Monitoring the variation in the wavelength of the light wave allows an amplitude of the acoustic wave to be estimated.

Optical device for detecting an acoustic wave

The invention is a device and method for detecting an analyte in a medium. An exciting light source produces an exciting light wave, which propagates to the medium and heats the latter. The device comprises a transducer for detecting the heating of the medium. According to one embodiment, the transducer is a thermal transducer, configured to detect a variation in the temperature of the medium. According to another embodiment, the transducer is an acoustic transducer, configured to detect a photoacoustic wave propagating from the medium. Whatever the embodiment, the transducer employs a membrane, on which a waveguide is placed. The waveguide comprises a resonant optical cavity. Transduction is achieved by analyzing a variation in a resonant wavelength of the optical cavity.

Photoacoustic or photothermal detector comprising an optical transducer

A measuring system includes a detector having an optical waveguide including a primary dopant capable of transmuting, by neutron capture, into a stable secondary dopant that is less neutron-absorbent than the primary dopant, a moderation layer suitable for slowing down fast neutrons, and an analysis device connected to the detector. The analysis device is configured to inject, into the waveguide, an interrogation wave having a wavelength corresponding to an absorption peak of the secondary dopant, detect a response wave emitted by the waveguide, calculate, from the detected response wave, a piece of information relating to a concentration of secondary dopant in the waveguide, and, based on the information relating to the calculated concentration of secondary dopant, determine a fluence of fast neutrons during a predetermined secondary period.

System for measuring fast neutron fluence for a nuclear reactor, associated installation, measurement method and computer program product

A signal-distributing device that includes an arrayed-waveguide-grating demultiplexer and at least one receiving module. Each receiving module includes a multimode interference coupler and two output waveguides, the multimode interference coupler being located between the arrayed-waveguide-grating demultiplexer and the two output waveguides. The multimode interference coupler is configured to distribute, to the two output waveguides, an optical signal delivered by the arrayed-waveguide-grating demultiplexer. Such a device allows wavelength shifts in the signal delivered by a set of one or more sensors, in particular Bragg grating reflectors inscribed in a given optical fibre, to be measured. It allows a wavelength shift to be measured with a high linearity and a signal-to-noise ratio.

Device for distributing a signal for measuring wavelength shifts

An optical fibre, for use in the field of distributed measurement of temperature or deformation by optical reflectometry in the frequency domain using the Rayleigh backscattered signal in the fibre, includes a core doped with nanoparticles for example formed from gold particles covered with zirconium oxide, and can be subjected to high temperatures during the measurement. A method for producing the optical fibre includes a step of heat treatment during which the optical fibre is subjected, for a duration of at least one hour, to a heat treatment temperature higher than a maximum temperature to which it will be subjected during a measurement.

Method for producing an optical fibre for a distributed measurement of temperature or deformation in a harsh environment using the Rayleigh backscattered signal

The field of integrated health monitoring using Bragg grating optical fibre sensors including a sensor and methods for locating and installing this sensor on a support. The Bragg grating optical fibre sensor includes an optical fibre wherein at least one set of patterns forming a Bragg grating is written, the optical fibre further including a set of microstructures in the vicinity of each Bragg grating, the microstructures being separate from the patterns forming the Bragg grating, each microstructure being capable of scattering a portion of a light beam within a predetermined range of scattering wavelengths.

Bragg grating optical fiber sensor associated with a scattering structure and methods for locating and installing such a sensor

A Bragg grating optical fiber sensor for measuring temperatures and deformations and a method for manufacturing same, the manufacturing method including ablating a mechanical coating over a portion of an optical fiber so as to form an opening extending radially over the entire thickness of the mechanical coating, and inscribing a Bragg grating into the optical fiber through the opening.

High-temperature-resistant Bragg grating optical fibre sensor and method for manufacturing same

A refractometer with blazed Bragg gratings. In order to measure the refractive index of a medium, for example a liquid or a gas, the refractometer includes a waveguide having a blazed Bragg grating, the spectral response of which depends on the refractive index of the medium and a light source in order to make this light interact with the grating. Further, spectral analysis of the light which has interacted with the grating is performed, the spectrum provided by the spectral analysis is recovered, and, from the recovered spectrum, the spectral response of the grating is correlated with one value of the refractive index of the medium.

Refractometer with blazed bragg gratings

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Meudon, France

Guillaume Laffont