Thomson-csf

Dominique Rojas

Marc Turpin

Herve Lefevre

Philippe Refregier

Michele Brevignon

Device for reading by optical sensor coherence

Disclosed is a shift sensor with birefringent optic fiber, wherein two fixed coupling points are provided. One movable coupling point, created by a coupling means, for which it is sought to measure the shift gets shifted over the fiber. A source emits a plane polarized wave along a neutral axis of the fiber. A coupled wave train is created at each coupling point. These coupled wave trains have a propagation speed which is smaller than that of the primary wave train. A detector enables the locating of the relative positions of the coupled wave trains and, hence, of the movable coupling point with reference to the fixed coupling points.

Shift sensor with optic fiber

An optic fiber hydrophone comprises a wide spectrum optical source, a super-luminescent diode for example, associated with an optic fiber assembly comprising chiefly a side-hole optic fiber, subjected to the field of pressure, forming a sensor, transmitting the optic radiation in the slow and fast modes respectively, and a second fiber, not subjected to the field of pressure, the neutral axes of which are oriented with respect to the neutral axis of the first fiber so that the wave transmitted in slow mode in one fiber is transmitted in fast mode in the other fiber, it being possible to connect these two fibers by a polarization maintaining fiber in the event that the sensor is offset with respect to the source, a polarizing fiber enabling the creation of the interferences, and a radiation detector at the output of the fiber assembly.

Growing community of inventors

Arcueil, France

Dominique Rojas