Electricite De France

Electricite De France - Service National

Jean-Pierre Gerardin

Herve J Arditty

Philippe Graindorge

Gilles Le Boudec

Dominique Meyet

Jean-Louis Lesne

A device for optically measuring the distance of a target (20) comprising a monomode coherent light source (18) means (18a, 21, 30) for periodically varying the wavelength of the light of the source, a photodetector (19) for detecting the variation in the wavelength between the light from the source (18) and that retroradiated by the target (20), and means (23, 24, 25; 33, 34, 35; 41, 43, 46) for processing the output signal of the photodetector (19) corresponding to the composite optical signal issuing from the cavity of the source of light and resulting from the re-injection into this cavity of the light retroradiated by the target (20), the frequency of the output signal of the photodetector being representative of the distance between the source (18) and the target (20).

Process and device for optically measuring the distance and the velocity

The discriminating device comprises an optical coupler (4) having at least three ends (5 to 8) to which are connected a semiconductor source of light (1) whose intensity is modulated, a semiconductor photoconductor (2) and an optical probe constituted by a multi-mode optical fibre (3) whose end has a pointed shape. This discriminating device is in particular applicable in a device for measuring the voluminal fraction of at least one fluid of a current of non-mixible fluids.

Device for discriminating fluids having different refractive indices and

The detector comprises an avalanche photodiode for receiving a light beam, a circuit for measuring the mean current across the avalanche photodiode and a bias voltage source. That source is controlled by the circuit for applying to the photodiode a bias voltage such that the mean current across the diode be substantially equal to an adjustable set value.

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Nanterre, France

Jean-Pierre Gerardin