Backscattering enhanced fiber distribution type temperature and strain dual-parameter sensing device and demodulation method thereof

Abstract

The invention discloses a backscattering enhanced fiber distribution type temperature and strain dual-parameter sensing device and a demodulation method thereof. The sensing device is composed of a narrow-linewidth light source, a coupler, an acousto-optic modulation module, a driver, an erbium-doped fiber amplifier, a circulator, a Raman wavelength division multiplexer, a sensing fiber having a plurality of continuous scattering enhanced point, a filter device, a photoelectric detector, a data acquisition card, and an upper computer. The implementation principle of dual-parameter measurementis as follows: on the basis of the sensitivity to the external environment change by a phase of a backscattering Rayleigh light signal in a sensing fiber and sensitivity to a temperature change by a Raman scattered light intensity, an implementation scheme of absolute temperature stress distributed measurement is provided by using an optical time domain reflection technology, a coherent detectiontechnology, a beat frequency signal cross correlation technology, a phase demodulation technology, a wavelength division multiplexing technique, and a temperature stress decoupling technique. Therefore, simultaneous measurement of a temperature field and a stress field continuously distributed along the optical fiber is realized. Moreover, the measuring distance is long; the spatial resolution ishigh; the sensitivity is high; the response speed is fast; and the error is small.

Description

technical field [0001] The invention relates to the technical field of optical fiber measurement of dual parameters, and in particular provides a backscattering-enhanced optical fiber distributed temperature and strain dual-parameter sensing device and a demodulation method thereof. Background technique [0002] In recent years, the development of optical fiber sensing technology has advanced by leaps and bounds, showing incomparable advantages compared with traditional sensors such as electrical sensors. Its main advantages are: no electromagnetic interference, good insulation; optical fiber corrosion resistance, safe use; High sensitivity; light optical fiber; many measurement objects; relatively small impact on the measured substance; strong reusability; convenient networking; low price; can be used in high temperature, high pressure, and high electromagnetic environments. [0003] Optical fiber sensing technology can be divided into point-type optical fiber sensing, quas...

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Problems solved by technology

However, its corresponding speed is relatively slow, the accuracy is not high enough, and it is difficult to demodulate data.

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