Centre National De La Recherche Scientifique

Thales

Université Nice Sophia Antipolis

Hoasys

Université Cote D'azur

Umberto Bortolozzo

Jean-Pierre Huignard

Daniel Dolfi

Stéphanie Molin

Stefania Residori

Arnaud Peigne

Martine Doisy

Renaud Bouffaron

Tommaso Occhipinti

Disclosed is an acoustic sensor including: —a component having an input and an output, the component being able to conduct light waves in a plurality of propagation modes between the input and the output, the component converting an acoustic signal to be measured into a phase shift proportional to an intermodal interference between at least two propagation modes, and —a detector of a physical quantity dependent on the phase shift.

Fibre-optic acoustic sensor and associated measurement system, vehicle and measurement method

A distributed optical fiber sensor of dynamic stress state comprises: an optical assembly configured to generate a series of optical pulses; an optical fiber of optical length L; an optical system configured to: inject through the first end at least the series of optical pulses; receive at the level of the end at least one series of output optical pulses, arising from the input pulses after propagation and retro-propagation in the fiber; generate at least one continuous reference beam or reference optical pulses on the basis of the optical assembly or of output optical pulses; produce a series of interference zones corresponding to the interference between the reference beam or a reference pulse and a signal optical pulse arising from an output optical pulse; a holographic detector comprising: a liquid-crystal light valve, the valve disposed so that it at least partially covers the interference zones, and producing holograms on the basis of the interference zones; at least one optical detector configured to detect output optical signals diffracted by the holograms.

Distributed optical fibre sensor for sensing stress state

A fiber optic sensor for detecting an excitation in proximity to a fiber optic assembly, the excitation inducing a modulation of the phase of an optical signal propagating in the fiber optic assembly, the sensor comprises: a laser assembly emitting at least one laser beam; a fiber optic assembly; an optical system configured to: inject at least one portion of the laser beam; generate at least one laser signal beam issued from the laser beam injected into and propagated in the fiber assembly; generate at least one reference beam from the laser beam or the signal beam; produce at least one interference zone corresponding to the interference between a portion of the reference beam and a portion of the interference signal beam corresponding to the interference between a portion of the reference beam and a portion of the signal beam; a digital holography assembly comprising: a liquid-crystal spatial light modulator; a video camera configured to receive the interference zone and to transcribe it electrically to the liquid-crystal spatial light modulator in order to create thereon a phase hologram corresponding thereto; at least one optical detector configured to detect an output optical signal beam.

Optical fiber sensor

An optical fiber sensor for locating an excitation in proximity to an optical fiber assembly comprises: a laser assembly configured to emit N laser beams indexed i with N&#x3e;1, of respective emission wavelength &#x3bb;i, an optical fiber assembly comprising N successive sections indexed i, an optical system configured to: inject the laser beams, receive N signal beams indexed i respectively of wavelengths &#x3bb;i, generate N reference beams indexed i respectively of wavelengths &#x3bb;i, produce N interference areas indexed i, a holographic detector comprising: a liquid crystal light valve that at least partially covers the interference areas, and is configured to produce N holograms indexed i from, respectively, N interference areas, at least one optical detector configured to detect N output optical signals indexed I, a processing unit adapted to identify the section of the fiber assembly situated in proximity to the excitation to be located.

Sensor with high-sensitivity optical fiber having a holographic detector comprising a liquid crystal light valve

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Juan les Pins, France

Umberto Bortolozzo