Phase-sensitive optical time domain reflectometry fiber distributed sensing system phase calculation method

A fiber-distributed, phase-sensitive light technology used in the use of wave/particle radiation, measurement devices, instruments, etc.

Active Publication Date: 2016-04-20
武汉雷施尔光电信息工程有限公司
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Problems solved by technology

[0004] The purpose of the present invention is to provide a phase-sensitive optical time-domain reflection optical fiber distributed vibration sensing system phase calculation method to solve the problem of accurately obtaining the phase change value introduced by the actual external vibration

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  • Phase-sensitive optical time domain reflectometry fiber distributed sensing system phase calculation method
  • Phase-sensitive optical time domain reflectometry fiber distributed sensing system phase calculation method
  • Phase-sensitive optical time domain reflectometry fiber distributed sensing system phase calculation method

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Embodiment 1

[0026] see figure 1 , a phase-sensitive optical time-domain reflection optical fiber distributed vibration sensing system, including a narrow linewidth laser 1, 1'2 fiber coupler 2, an acousto-optic modulator 3, an erbium-doped fiber amplifier 4, a fiber circulator 5, and a sensing fiber 6, 2′2 fiber coupler 7, balanced light detector 8, data acquisition card 9, computer 10.

[0027] The components of each part of the system are described as follows:

[0028] Narrow linewidth laser 1, used to generate long coherence length laser;

[0029] 1'2 fiber optic coupler 2, used to divide the laser into two paths, one path is used for the sensing light path, the other path is used for the reference light path, the optical power of the sensing light path is much greater than that of the reference light path, and the coupling splitting ratio can be selected as 90:10;

[0030] The acousto-optic modulator 3 is used to modulate the laser into a pulsed laser, and at the same time, allow th...

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Abstract

The invention discloses a phase-sensitive optical time domain reflectometry fiber distributed sensing system phase calculation method comprising the following steps that beat frequency digital signals corresponding to multiple times of optical pulses are acquired; a backscattering optical phase matrix phi is obtained; an external vibration disturbance position Y is determined; positions X and Z without phase disturbance are respectively selected before and after the external vibration disturbance position Y, phase unwrapping of the corresponding phases phiX and phiZ of the positions X and Z without phase disturbance in the backscattering optical phase matrix phi is performed, and phase change is extended to the range from negative infinite to positive infinite; and the phase curve of the position Z after vibration subtracts the phase curve of the position X before vibration and then is divided by 2 so that a phase change value introduced to Y by external vibration is obtained. According to the calculation method, the phase change value introduced to the optical pulses by the external vibration event in a phi-OTDR fiber distributed sensing system can be accurately obtained, and the method is based on a conventional phi-OTDR fiber distributed sensing system with no requirement for complex algorithm.

Description

technical field [0001] The invention relates to a phase calculation method of an optical fiber distributed vibration sensing system, in particular to a phase-sensitive optical time domain reflection optical fiber distributed vibration sensing system phase calculation method, and the invention belongs to the field of optical fiber sensing technology application. Background technique [0002] Phase-sensitive Optical Time Domain Reflectometry (Phase-sensitive Optical Time Domain Reflectometry, abbreviated as Ф-OTDR or Phase-sensitiveOTDR) optical fiber distributed sensing system is used to monitor external vibration disturbance events, which can realize the precise location of external vibration disturbance events, with Linear distributed measurement, remote measurement, high sensitivity, strong anti-electromagnetic interference ability, good insulation, intrinsically safe, light weight and small size, etc., are widely used. In the field of petrochemical industry, Ф-OTDR can re...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01H9/00
CPCG01H9/004
Inventor 庞拂飞贺梦婷梅煊玮陈娜王廷云
Owner 武汉雷施尔光电信息工程有限公司
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