Distributed Optical Fiber Sensor for Multi-point Temperature Measurement

摘要

The distributed optical fiber temperature sensor is set up by using the technique of optic time-domain reflection (OTDR) to get temperature information, and the way of getting the mean by the accumulating time-domain signal to improve the ratio of signal to noise. Base on the theory of Optical Time Domain Reflectometer, Raman scattering distributed optical fiber system for Multi-point temperature measurement is established. A new demodulation method is proposed, that is circulation demodulation method. The OTDR temperature curve of the next point to be measured is demodulated by the current OTDR temperature curve. The experiment validated that the theoretical analysis is correct, and the system can inhibit the calculation of temperature noise and prevent Rayleigh back scattering light from harassing anti-Stokes back scattering light. The spatial resolving power is less than 3m, the temperature resolving power is about ± 3° C, and time resolving power is not more than 3min.