Performance Enhancement of Raman Distributed Temperature Sensor By Piecewise Linear Compensation Algorithm

As to the Raman scattering based distributed optical fiber temperature sensing system, the temperature demodulation algorithm has great influence on the temperature measurement accuracy. So, the data for the temperature demodulation need noise suppression and position correction. In addition, the walk-off effect of Raman Stokes and Raman anti-Stokes light and the fiber reference temperature calibration restrict the long-distance distributed temperature measurement, and corresponding signal processing algorithm should be adopted to solve the above problems. Based on the typical temperature demodulation theory that relies on the Raman Stokes and anti-Stokes data, an optical fiber attenuation compensation scheme for the fiber reference temperature calibration and a signal walk-off effect correction algorithm are proposed and experimentally demonstrated, and the measurement dynamic range obtained is larger than 20dB, and along an optical fiber with length of about 8km, it achieves measurement accuracy of 0.5 °C and 1m spatial resolution.