The optimum designs of 30km distributed optical fiber Raman Photons Temperature Sensors and measurement network

The distributed optical fiber Raman Photons Temperature Sensors (DFRS) is a real time, on line and multi-point (30k points) measuring system for multi-parameter measurement of temperature etc. According to temperature effect of optical fiber Raman backscattering, the intensity of anti-stokes Raman backscattering of optical fiber is modulated by the spatial temperature field where the optical fiber is laid. Then after signal processing and demodulation, the information of temperature can be extracted from the noise and can be displayed in real time. It is a typical optical fiber sensors measuring network. In time domain, using the velocity of light wave in optical fiber, the time interval of back-direction light wave and optical fiber OTDR technology, the DFRS can locate the temperature spots. In this case, it is a typical optical fiber laser temperature radar system as well. The backscattering spectrum of optical fiber has been measured by fiber laser and optical spectrum analyzer. Raman backscattering spectrum and ZX band backscattering spectrum has been first observed. The amplification of anti-stokes Raman spontaneous scattering (ARS) and the temperature effect have been first observed and applied to DFRS. The performance of DOFS is following: fiber length: 25.2km; temperature measuring range: 0-100°C(can be expand) temperature uncertainty: ±2°C: temperature resolution: 0.1; spatial resolution: 5m: measurement time: 10min; Main unit operation temperature range: 0-40°C. The optical fiber sensor probes and the software for signal processing are also discussed.