Distributed fiber optic temperature sensor and its three-demodulation algorithm

Abstract

The invention discloses a distributed optical fiber temperature sensor and its temperature triple demodulation algorithm. The temperature sensor includes a temperature measuring optical fiber and a pulse laser, an integrated optical fiber wavelength division multiplexer, a Stokes scattered light photoelectric conversion amplification module, Anti-Stokes scattered light photoelectric conversion amplifier module, data acquisition card and demodulator composed of computer, integrated optical fiber wavelength division multiplexer connected with pulse laser, temperature measuring fiber and two photoelectric conversion amplifier modules at the same time, pulse laser , two photoelectric conversion amplification modules and the computer are all connected with the data acquisition card, and the demodulation algorithm involved in the present invention is improved into three demodulation algorithms by a single demodulation algorithm, namely low temperature (below 0 ℃), normal temperature (0~120 °C) and high temperature (higher than 120 °C) set the sensor demodulation algorithm to demodulate the cubic curve fitting formula, the first curve fitting formula demodulation and the quadratic curve fitting formula demodulation respectively. The invention has the advantage that it can obtain ultra-high temperature measurement accuracy in the whole temperature range.

Description

[0001] Technical field: [0002] The present invention relates to the technical field of temperature sensors, specifically a method that can solve the problem of high temperature measurement accuracy at normal temperature and low temperature measurement accuracy at low temperature and high temperature of traditional distributed optical fiber temperature sensors, so as to obtain high temperature measurement accuracy in the whole temperature range Distributed fiber optic temperature sensor and its temperature three-demodulation algorithm. [0003] Background technique: [0004] In 1981, the University of Southampton in the UK first proposed the concept of a distributed optical fiber temperature sensor. In 1983, Hartog et al. developed a specific experimental device. In 1985, Dakin in the United Kingdom carried out a temperature measurement experiment of a distributed optical fiber temperature sensor in the laboratory, in which the light source was a neon ion laser; in the same ye...

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Problems solved by technology

[0009] Another technical problem to be solved by the present invention is to provide a solution to the cubic curve fitting formula in three temperature segments of low temperature (below 0°C), normal temperature (0-120°C) and high temperature (higher than 120°C). Three different demodulation algorithms and three calibration coefficients corresponding to the algorithms, so as to solve the problem of high temperature measurement accuracy of traditional distributed optical fiber temperature sensors at room temperature. , and the temperature three demodulation algorithm for the problem of low temperature measurement accuracy at low temperature and high temperature

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