Photonetics

Photonetics S.a.

Luc Jeunhomme

Herve J Arditty

Francois X Desforges

Francois-Xavier Desforges

An optical-fiber detection device which involves testing for correct operation is provided with at least one sensor having a sensing element which operates by light reflection at the end of an optical fiber and with a line for transmission of light by optical fibers. The transmission line connects the sensor to a source of periodic light pulses and to an electronic signal detection and processing unit. The sensor includes an optical fiber segment of predetermined length between the sensing element and an intermediate connection which produces a state pulse by reflection. The sensing element produces a measurement pulse which is separated from the state pulse by an elementary time interval. The electronic unit serves to detect the state of operation of the sensor by means of the presence or absence of the state pulse or reference pulse in the signals.

Optical-fiber detection device which involves testing for good

A vibration detection device is provided having multimode optical fiber as sensitive element; a coherent light source; photodetecting means; means for analyzing the output of the photodetector means; a monomode optical fiber disposed between the coherent light source and the first end of the multimode optical fiber forming the input face thereof; and at least one optical fiber, whose core diameter is smaller than that of the multimode optical fiber, disposed between the other end of the multimode optical fiber, forming the output face thereof and on which a speckle appears, and the photodetector means.

Device for detecting vibrations including a multimode optical fiber as

In an optical fiber sensor, the fiber has a sensitive zone which cooperates with a retroreflecting surface through the agency of an optical couplant. The function of the retroreflecting surface is to return into the optical fiber all light losses which escape from the fiber in the sensitive zone.

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Fontenay le Fleury, France

Luc Jeunhomme