Evaluation of Fiber Optic Raman Scattering Distributed Temperature Sensor Between –196 and 400 °C

Abstract

Distributed temperature sensors have been proposed for a wide variety of scientific and industrial applications and represent an important technology for modern infrastructures. Due to the range of potential applications, distributed fiber optic sensors based on spontaneous Raman scattering have been studied both theoretically and experimentally. This article presents the experimental evaluation of a distributed fiber optic temperature sensor based on spontaneous Raman scattering over a wide temperature range, from -196 °C to +400 °C. The sensor is implemented using a commercial OTDR, a standard EDFA amplifier and a standard optical fiber link. Besides, a special type of optical fiber for high temperature operation, featuring metallic coating, is also assessed as the sensor element. The integrity of the fibers following the exposure to the extreme temperatures is analyzed. The results provide values for the sensitivity, accuracy and resolution of the sensor in the wide range of temperatures.