Optical fibre sensor for measuring a parameter, procedure for evaluating the parameter, and application of the sensor to gas measurement.

摘要

It is a system of optical fibre sensors comprising at least one such fibre for measuring a physical or chemical parameter which can change in an environment (E), within which the sensor is placed, the said fibre comprising cladding (3), a core (5) surrounded by this cladding, an axis (7) with a length in the direction of this axis, and, locally along its length, parts (9) with optical thickness variations, forming an optical diffraction grating (10), at least part of the cladding (3) comprising in its construction an active material whose optical properties vary as a function of the change in the said parameter (P) within the environment where the sensor is placed. The active material may be a heteropolysiloxane. In order to analyse the change in the parameter, reflectometric analysis may be provided. Application in particular to determining the gas content of a mixture. <IMAGE>