Studies on attenuation corrected temperature demodulation in single ended Raman distributed temperature sensors

Abstract This paper presents an attenuation compensation technique for Raman distributed temperature sensors (RDTS) using Raman Anti-Stokes (AS) light in a single ended configuration. The proposed method consists of two main stages: a calibration stage, in which the attenuation profile of the sensing fiber is captured, and a measurement stage comprising attenuation correction followed by temperature estimation. Attenuation compensation is performed using the stored attenuation profile, while a dynamic self-calibration scheme based on a reference fiber section is employed to mitigate variations in laser power, fiber coupling efficiency and photodetector gain. The proposed technique is experimentally validated using a 450 m long sensing fiber. Experimental results demonstrate a temperature estimation accuracy of ± 0.8 °C over a sensing range of 20–70 °C, with a temperature resolution of 0.35 °C and a spatial resolution of 3.4 m. The method achieved a maximum temperature estimation error of ± 1.3 °C after the introduction of a splice and exhibited a maximum error of 3.4 °C during a 20-day stability study conducted under an unchanged fiber layout and moderate ambient temperature variations. These results demonstrate that the proposed approach provides attenuation compensation using only the AS channel while maintaining measurement performance comparable to existing methods, thereby simplifying the RDTS system and eliminating errors associated with wavelength dependent loss and walk-off effects.