Patent ID: 6511222
Filing Date: 2003-01-28
Classification: G01K

Abstract:
A first optical fibre temperature sensor including an optical source for supplying an optical signal, a first fibre optic transmission line connected to the optical source, a sensitive portion connected to the first fibre optic transmission line, a second fibre optic transmission line connected to the sensitive portion, and a first optical detector and processing circuit connected to the second fibre optic transmission line for receiving and analyzing the optical signal transmitted by the optical source and passing through said sensitive portion, said sensitive portion of the optical fibre being arranged according to a network of bends over a determined length (N1) and with a determined amplitude of curvature (A1), characterized in that the sensitive portion, formed as a section of optical fibre or integrated optical guide, is intrinsically insensitive to temperature, said sensitive portion of core and cladding materials including an outer cladding of decreasing refraction indices, being covered with at least one additional layer of a material having a lower refraction index than the refraction index of the outer optical cladding of the sensitive portion and with different optical properties, as regards temperature, to those of the core of this sensitive portion, so as to make said portion temperature sensitive via positive or negative modulation of the local numerical aperture of said section of optical fibre or integrated optical guided.