Detecting method suitable for optical fiber distributed temperature and stress sensing device

Abstract

The invention discloses a detection method suitable for a sensing device of optical fiber distribution type temperature and stress. The sensing device of the optical fiber distribution type temperature and stress mainly comprises a light source module (1), a frequency discriminator module (2), and a thermo tank module (3), which are all connected with one another by polarization-preserving fiber. The detection method of the invention is a direct detection method which is based on optical fiber Raman scattering used as a carrier wave of temperature information, brillouin scattering used as a carrier wave of stress, rayleigh scattering used for measuring the relative frequency of a outgoing laser beam to the frequency discriminator and Fabry-Perot etalon used for discriminating frequency and distributing sensing temperature and stress. The invention has the advantages of simple structure, fine stability, avoidance of outgoing power of the light source during coherent detection, and outgoing frequency of the light source. Instability of acoustic modulation or electro-optic modulation frequency is directly referred to measure errors and the direct detection technology of frequency discrimination is not sensitive to the frequency drift of the light source and the fluctuation of signal intensity.

Description

technical field [0001] The invention relates to a sensing technology, more particularly, to a detection method for a temperature and stress sensing device connected by full optical fiber. Background technique [0002] Distributed optical fiber sensors can be embedded in the material structure to form a smart material structure (Smart Structure) to realize real-time self-detection and self-diagnosis of the structure itself, which can be applied to: (1) high-rise buildings, intelligent buildings, bridges, highways and other disastrous Online, dynamic detection, protection and alarm; (2) Online, dynamic detection of aviation and aerospace vehicles and neural network system of robots; (3) Temperature distribution measurement, thermal protection and fault diagnosis of various large and medium-sized transformers and generator sets , underground and overhead high-voltage power cables, thermal power plant piping temperature detection, heating system (warm water, heating) pipes; (4) ...

AI Technical Summary

Problems solved by technology

Compared with the existing coherent detection means, the detection method of the present invention effectively solves the problem of cross-sensitivity between multiple measured parameters; through the dual-channel Fabry-Perot etalon for differential measurement and frequency offset, it solves the problem of large temperature zero ~400℃ measurement range problem

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