Distributed optical fiber acoustic sensing device and method based on dual polarization double sideband modulation

Abstract

The invention discloses a distributed optical fiber sound sensing device and method based on dual-polarization double-sideband modulation. The distributed optical fiber sound sensing device comprisesa narrow linewidth laser source (1), a polarization-maintaining optical fiber isolator (2), a dual-polarization four-parallel Mach-zehnder electro-optic modulator (3), an arbitrary waveform generator(4) for drive in an X polarization direction, an arbitrary waveform generator (5) for drive in a Y polarization direction, an electro-optic modulator bias control panel (6), a 1*2 polarization-maintaining optical fiber coupler (7), an optical fiber polarization beam splitter (8), a first erbium-doped optical fiber amplifier (9), a first optical fiber (10), an optical fiber circulator (11), a second erbium-doped optical fiber amplifier (13), a second optical fiber (14), a four-way output-type 90-degree light mixer (15), a balance photoelectric detector (16), a data acquisition card (17) and a processing unit (18). The distributed optical fiber sound sensing device integrates the advantages of time-domain reflection and frequency-domain reflection, is free from electromagnetic interference,is electrically passive and can achieve distributed sound sensing with a large dynamic range and high spatial resolution.

Description

Technical field [0001] The invention relates to the technical field of optical fiber sound sensing measurement, in particular to a distributed sound sensing device and measurement method based on digital dual-polarization double-sideband modulation. Background technique [0002] With the development of optical fiber sensing technology in recent years, optical fiber sound sensing measurement has become one of the main research fields. It has a wide range of application requirements in the safety monitoring of long-distance field transmission pipelines, marine geology and offshore oil exploration, and aviation aircraft aerodynamic noise source detection. [0003] Acoustic wave detection technology uses the propagation changes of acoustic wave signals in elastic media to detect, identify and locate the detection target. Most of the existing microphone arrays are constructed with electrical microphones. The discrete structure of electronic sensors requires strict synchronization acqui...

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Problems solved by technology

[0005] (1) Interferometric detection method, the light source used is continuous laser, so the disadvantage of this type of method is that it cannot detect multi-point vibration at the same time;

[0006] (2) Phase-sensitive optical time-domain reflectometry, its single detection method makes the optical pulse width and pulse energy need to be compromised, which limits the simultaneous improvement of the spatial resolution, signal-to-noise ratio and dynamic range of the system, and it is difficult to meet the real sound wave distribution Sensing requirements

Existing technologies have major deficiencies in the complete and high-fidelity recording of information such as the amplitude, phase, and frequency of acoustic waves at each position of the optical fiber

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