LANDAU PLACZEK RATIO APPLIED TO DISTRIBUTED FIBER SENSING

It is shown experimentally that the ratio of the intensities of Raylei gh and Brillouin backscattered light (Landau Placzek ratio) in an opti cal fibre has a temperature dependence which may be used for the basis of a distributed temperature sensor. This result, combined with the k nown frequency dependence of the Brillouin backscattering on temperatu re and strain, indicates that spontaneous Brillouin backscatter may be used for the unique determination of either temperature or strain in a distributed optical fibre sensing system.