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With the rapid development of modern society, the advent of the era of big data makes the exchange of information increasingly frequent and important. The distributed fiber Raman temperature measurement system is a brand-new sensing technology that has rapidly developed in recent years. As a transmission medium, it uses spontaneous Raman scattering to acquire back Raman scattering signals through a high-speed acquisition card. Since this signal carries temperature information, this signal is amplified and denoised and then demodulated to obtain a curve with temperature information. In this paper, we study the optical fiber temperature sensing scheme based on Raman scattering and analyze its working principle. By analyzing and comparing the demodulation method of sensor temperature, a method of demodulating temperature at different temperatures by using anti-Stokes fiber temperature as a reference channel is proposed. The relationship between the Raman ratio and the distance is demodulated. Because the traditional calibration scheme fails to take the environmental temperature value into account, this paper adopts a novel dynamic multi-segment fiber temperature calibration method, and verifies the feasibility of the calibration scheme through experiments. The result shows that with the change of the external environment temperature, the temperature of the sensing fiber can be accurately demodulated, the temperature demodulation result is more accurate, the measurement error is less than 1°C. The resulting system is more stable and can adapt to complex environmental changes. Since the light will become soft under high temperature conditions, this paper calculates the relationship between fiber loss coefficient and temperature. It is found that the continuous summation method can better solve the loss problem, thereby effectively improving the system signal-to-noise ratio.
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