Recent advances in distributed optical fibre temperature sensing using the Landau-Placzek ratio

Abstract

Distributed optical fibre temperature sensing (DTS) provides an elegant way of monitoring the temperature at many points without necessitating the accurate positioning of individual discrete sensors. This paper demonstrates recent advances in distributed temperature sensing based on spontaneous Brillouin scattering. A high spatial and temperature resolution is achieved by exploiting a novel low cost detection system. The experimental configuration consists of two key components; a Q-switched laser source to generate the backscattered signal and the low cost detection system which comprises an in-fibre double pass Mach-Zehnder interferometer and a sensitive InGaAs APD connected to a computer based averaging system. It is the relative low cost of these components which has made the Brillouin based temperature sensor so attractive for commercial exploitation. A spatial resolution of 3.0 metres with a Brillouin temperature resolution of 0.9°C at a range of 16km has been achieved.

SPIE Distributed and Multiplexed Fibre Optic Sensors VII 1-5 Nov (1998)

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