Thales

Thomson-csf

Centre National De La Recherche Scientifique

Université Nice Sophia Antipolis

Martine Doisy

Jean-Pierre Huignard

Daniel Dolfi

Stéphanie Molin

Jean-Paul Pocholle

Claude Weisbuch

Baudouin De Cremoux

Umberto Bortolozzo

Raphael Lardat

Stefania Residori

Raphaël Lardat

Gérard Roux

Renaud Bouffaron

Bernard Raveau

Gerard Roux

Alain Aspect

Daniel Bloyet

Didier Robbes

Ronan Stephan

Jackie Provost

Arnaud Peigne

Loïc Morvan

Marc L Sing

Christian Bergogne

Yves Montfort

François-Xavier Launay

Marc Himbert

Francois-Xavier Launay

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 non-acoustic measurement unit is provided to be integrated into an all-optical acoustic antenna, the non-acoustic measurement unit including a portion of an optical fiber, termed non-acoustic, intended to convey non-acoustic measurements, at least one non-acoustic sensor with electrical output able to deliver at least one electrical signal representative of at least one physical quantity, and a passive electro-optical transducer subjected to the electrical signal, the passive electro-optical transducer acting on a mechanical constraint undergone by a first sensitive zone of the optical fiber portion, in such a way that a value of a measurable property of a first optical signal conveyed by the non-acoustic optical fiber is representative of the electrical signal, and at least one photovoltaic cell coupled electrically to the non-acoustic sensor so as to electrically supply the sensor.

Non-acoustic measurement unit

The invention consists of an optical hydrophone, an optical fiber element forming a laser cavity, housed in a mechanical structure which comprises an open cylindrical rigid body, defining the cavity enclosing a fluid and in which the optical fiber element is housed, and closed at its ends by two end caps which keep the optical fiber element permanently under tension, in a longitudinal rectilinear position inside the cavity. The end caps are configured in such a way that when the exterior pressure varies, they undergo a deformation giving rise to a variation in the length of the optical fiber element and that when the temperature varies, they undergo a deformation giving rise to a variation in the length of the optical fiber element which compensates for that induced on this element by the temperature variation. The mechanical structure furthermore exhibits one or more orifices allowing equilibration of the static pressures.

All-optical hydrophone insensitive to temperature and to static pressure

The subject of the present invention is a dynamic sensor of physical quantities with optical waveguide with optically-pumped amplifier medium, which requires no interferometer or reference sensor and which makes it possible to obtain at least the same level of performance, in terms of sensitivity, as known sensors of this type, and this waveguide is linked at one end to a selective mirror, and comprises at its other end an interrogation laser, the reflection of which on the selective mirror produces a wave which, by interference with the incident wave, provokes the periodic saturation of the gain of the waveguide.

Dynamic sensor of physical quantities with optical waveguide with optically pumped amplifier medium

The general field of the invention is that of fiber-optic sensors comprising at least one measurement optical fiber having an optically pumped doped amplifying medium, the optical characteristics of which are sensitive to a physical quantity, the fiber having at least one Bragg grating. The fiber is designed so as to generate, in the amplifying medium, two optical waves having different optical frequencies that propagate in the same direction after reflection on the Bragg grating and are emitted by the amplifying medium, the two optical frequencies depending on the physical quantity. The two waves may be generated using either a birefringent polarization-maintaining fiber or a DBR (Distributed Bragg Reflector) laser cavity. Notably, this sensor may be used as a hydrophone.

Self-referenced optical fiber sensor and related sensor network

A system for the optical pumping of a cell of atomic or molecular gases comprises at least one optical cavity comprising at least one cell of atomic or molecular gases, one optical pumping wave being coupled to the optical cavity.

System for the optical pumping of a cell of atomic or molecular gases

In a magnetic field measuring device, conveyed by a carrier vehicle and released from this vehicle in order to be put into action, the excitation means and the measuring means of a nuclear magnetic resonance helium magnetometer are separated. These measuring means are fixed to a body which includes devices for the transmission and exploitation of the measurements given by the measuring means, and this set is released after the exzcitation is completed while the excitation means remain fixed in the carrier vehicle. This makes it possible to fabricate smaller and lighter magnetic localizing buoys.

Magnetic detection method and device for the implementation thereof

A superconducting magnetometer, using a superconducting compound at the temperature of liquid nitrogen, is disclosed. It consists in the use, as a sensitive element, of a piece of superconducting material with a central constriction enabling the demarcation of a channel in which the number of useful, intrinsic loops is sufficiently limited for the sensitive element to behave like a DC SQUID with a single loop.

Superconducting DC SQUID magnetometer working in liquid nitrogen

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Plascassier, France

Martine Doisy