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Distributed fiber sound wave detection apparatus and method based on wave beam formation

A distributed optical fiber and sound wave detection technology, which is applied in measuring devices, measuring ultrasonic/sonic waves/infrasonic waves, using wave/particle radiation, etc., can solve the problems of difficult reliable operation of electronic sensors, achieve small size, improve flexibility, and expand effect of scale

Active Publication Date: 2015-11-25
TIANJIN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The harsh working environment such as electromagnetic interference, high temperature and high humidity also brings great difficulties to the reliable work of traditional electronic sensors.

Method used

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  • Distributed fiber sound wave detection apparatus and method based on wave beam formation
  • Distributed fiber sound wave detection apparatus and method based on wave beam formation
  • Distributed fiber sound wave detection apparatus and method based on wave beam formation

Examples

Experimental program
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Effect test

Embodiment 1

[0028] Embodiment 1: Distributed optical fiber acoustic wave detection device based on beamforming

[0029] Such as figure 1 As shown, the light source 1 emits frequency ω 0The continuous laser light passes through the 1x2 coupler 2, and is divided into two paths of local reference light and signal light: the local reference light passes through the reference arm light 6, and reaches the 90° optical mixer 14; The parallel Mach-Zehnder electro-optic modulator 5 is modulated to simultaneously contain the frequency ω 0 -ω CW fixed frequency components and frequency ω 0 Pulse signal light with +ω(t) linear frequency sweep component (such as figure 2 shown); the pulse signal light is amplified successively through the erbium-doped fiber amplifier 7, filtered by the optical filter 8 and unidirectionally transmitted by the circulator 9, and then injected into the reference length optical fiber 11 and the sensing optical fiber 13 specially arranged, and the pulse After the signa...

Embodiment 2

[0045] Embodiment 2: Distributed optical fiber acoustic wave detection method based on beamforming

[0046] Such as figure 1 As shown, the light source 1 emits frequency ω 0 The continuous laser light passes through the 1x2 coupler 2 and is divided into two paths of local reference light and signal light; the local reference light passes through the reference arm 6 and reaches the 90° optical mixer 14; the signal light passes through the two-way parallel light controlled by the arbitrary waveform generator Mach-Zehnder electro-optic modulator 5, is modulated as figure 2 The shown double sideband heterogeneous optical pulse, the lower sideband is fixed frequency ω 0 -ω CW , the upper sideband frequency is ω 0 +ω(t); the pulse signal light is amplified by the erbium-doped fiber amplifier 7, the optical filter 8 and the circulator 9 successively, and then injected into the sensing fiber, and the pulse signal light is scattered back Rayleigh in the passing optical fiber 13 R...

Embodiment 3

[0048] Embodiment 3: application example

[0049] In construction sites and mountainous road areas where slope stability monitoring is required, the distributed optical fiber acoustic wave detection device based on beamforming of the present invention is used to monitor characteristic low-frequency sound waves and locate the sound source, so as to detect impending accidents near the sound source in advance Make predictions and alerts. Bury the sensing fiber 13 in the area that needs to be monitored, and the arrangement includes a one-dimensional linear sensing fiber 20, a two-dimensional square sensing fiber 21, and a three-dimensional conical sensing fiber 22. The fiber optic acoustic wave detection method is used to extract the acoustic signal.

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Abstract

The invention discloses a distributed fiber sound wave detection apparatus and method based on wave beam formation. The apparatus comprises a light source, a 1*2 coupler, a control and signal processing unit, an arbitrary waveform generator, a double-channel parallel Mach-Zehnder electro-optical modulator, a reference arm fiber, an erbium doped fiber amplifier, an optical filter, an annular device, a front-end reflector, a reference length fiber, a rear-end reflector, a sense fiber, a 90-degree optical mixer, and a balance detector. The method includes the steps: injecting signal light into the sense fiber, the signal light being modulated to be light pulses with a fixed frequency on a lower side and a sweep frequency on an upper side; mixing the returned signal light carrying light phase information and light frequency spectrum information of detecting points with local reference light; demodulating the light phase information and the light frequency spectrum information, and obtaining the frequency, amplitude and phase information of sound waves in the detecting points in the sense fiber; and finally calculating the position, intensity and frequency information of sound sources. The sensing function and the transmission function of a fiber are combined into one function. Therefore, the distributed fiber sound wave detection apparatus and method have the advantages that the detecting point scale is hundred times higher than that of the prior art.

Description

technical field [0001] The invention relates to the technical field of distributed optical fiber acoustic wave detection, in particular to a distributed optical fiber acoustic wave detection device and detection method based on beam forming. Background technique [0002] Acoustic measurement technology is an important detection method and an important research direction in petroleum, geotechnical, aviation and other fields, and has a wide range of applications and needs. Acoustic beamforming technology uses a microphone array to receive sound field signals, and through phase processing of each microphone signal, the signal corresponding to the focal point position of the real sound source is strengthened to form a "main lobe", while the signals at other focal point positions are attenuated to form a "side lobe". ”, so that the characteristics of the sound source can be identified efficiently and reliably. For example, in oilfield exploration and development, acoustic loggin...

Claims

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Application Information

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IPC IPC(8): G01H9/00
Inventor 江俊峰刘铁根刘琨陈文杰王双
Owner TIANJIN UNIV
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