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Joachin Honthaas

Herve Lefevre

Eric Ducloux

Jean-Jacques Bonnefois

Frederic Guattari

Cedric Molucon

Cedric Alain Jacky Molucon

Hervé Lefevre

Frédéric Guattari

Hervé Claude Lefevre

Cédric Alain Jacky Molucon

An interferometric measurement device includes a broad-spectrum spontaneous emission light source; a measurement interferometer, receiving a light signal with input light power and delivering a modulated light signal with output light power, the modulated light signal being modulated at a modulation frequency, depending on a physical parameter to be measured and being proportional to the input light power; an optical radiation detector, receiving the modulated light signal exiting from the measurement interferometer and delivering a modulated electrical signal representative of the output light power; a filtering interferometer, insensitive to the physical parameter to be measured, having a free spectral range ISL and a finesse F selected such that an interval of frequencies, centerd around an optimal frequency fequal to (2k+1)ISL/2, k being a natural number, and of width &#x394;f equal to [0.9&#x2212;(3/2F)]ISL, includes the modulation frequency of the modulated light.

Interferometric measurement device comprising a filtering interferometer

A fiber-optic interferometric measurement device () intended to measure a physical parameter (QR), includes: a wide-spectrum light source (); a SAGNAC fiber-optic interferometer (), in which there propagate two counter-propagating light waves () including measurement elements () sensitive to the physical parameter that results in a non-reciprocal phase difference &#x394;&#x3c6;&#x3c1; between the two light waves; and a detector () delivering an electric signal representative of the physical parameter. The measurement elements include a ring resonator () in transmission mode including a first coupler () and a second coupler () respectively, which couple a first arm () and a second arm () respectively of the SAGNAC interferometer to the ring resonator, in such a way that the two light waves travel in opposing directions of travel (H,AH).

Fibre-optic interferometric measurement device comprising a ring resonator, gyrometer and inertial attitude or navigation unit comprising such a device

Disclosed is a fiber optic interferometer including: a wideband optical source having a decoherence time &#x3c4;; a coil including N turns of a fiber optic with length L; an optical element separating the incident beam into first and second beams coupled to first and second ends of the fiber respectively, so the first beam travels through the fiber optic in a first direction and the second beam travels through the fiber optic in a counter propagating direction; and a detector detecting the intensity of the output beam. The fiber optic is a high polarization mode dispersion type, and the length L of the fiber optic coil is more than twice the fiber correlation length, so the fiber operates in a coupled PMD mode, and the propagation differential group delay between two orthogonal polarization states, accumulated over the length of the fiber, is greater than the decoherence time of the source.

Interferometer with a fiber optic having a high PMD in coupled mode, fiber optic gyroscope (FOG), and inertial navigation system including such a gyroscope

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Paris, France

Joachin Honthaas