The application and principle of distributed fiber optic temperature measurement

Temperature measurement is an important parameter for detection and control, which has always been valued by people. In today’s rapidly developing technology, the measurement of temperature information has more profound significance. Distributed fiber optic temperature sensing technology has become a remarkable new technology in fiber optic sensing technology due to its continuous and real-time measurement of the temperature field distributed along the fiber optic. This technology has been widely applied in the fields of power industry, petrochemical industry, aerospace industry, nuclear industry, etc. The common distributed fiber optic temperature measurement method is to obtain the light intensity ratio of anti Stokes and Stokes, then attenuate and compensate for the ratio data, and finally obtain the temperature through demodulation formula. However, in practical applications, the signal received by the photoelectric detection module is not the intensity of the anti Stokes light and Stokes light at different positions in the fiber, but the intensity of the anti Stokes light and Stokes light after attenuation and loss through backward propagation in the fiber. Therefore, it is necessary to compensate for the attenuation of the signal received by the photoelectric detection module.

The distributed fiber optic temperature measurement method fits the intensity ratio signal of anti Stokes light and Stokes light in segments based on the attenuation point data of the fiber optic. Then, the actual obtained ratio line data is divided by the fitted baseline data, and the division result is calibrated to obtain the fiber optic temperature. The present invention expands the scope of use of distributed fiber optic temperature measurement, allowing for normal temperature measurement even in cases of poor fiber quality. By using the segmentation method to attenuate and compensate for the light intensity ratio signal of anti Stokes and Stokes, the temperature curve demodulated by the system is consistent with the actual situation, thereby improving the temperature measurement accuracy and reliability of the temperature measurement system.