Unlock instant, AI-driven research and patent intelligence for your innovation.

A composite optical fiber sensing system and sensing method

An optical fiber sensing system and a composite technology, applied in measuring devices, instruments, measuring ultrasonic/sonic/infrasonic waves, etc., can solve problems such as low frequency response, high false alarm rate, and inability to identify vibration events, and achieve low noise levels , low false alarm rate, and high positioning accuracy

Active Publication Date: 2017-11-28
天津精仪精测科技有限公司
View PDF4 Cites 0 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, because the frequency of its transmitted pulse is limited by the length of the optical fiber, its frequency response is very low, which makes it impossible to effectively identify vibration events, and the false alarm rate is high.

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Image

Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
  • A composite optical fiber sensing system and sensing method
  • A composite optical fiber sensing system and sensing method
  • A composite optical fiber sensing system and sensing method

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0042] A composite optical fiber sensing system based on the principle of phase-sensitive OTDR, the principle of Mach-Zehnder interferometer, and the principle of FBG wavelength division multiplexing, including: laying a sensing optical fiber 6 in the range where vibration needs to be detected, and using the sensing optical fiber 6 As a sensor and signal transmission medium, vibration detection and monitoring are realized; an ultra-narrow linewidth laser light source 1 (linewidth hundreds of kHz) is used as a part of the light source of the phase-sensitive OTDR (optical frequency v 1 ), injecting detection light into the sensing fiber 6 in the forward direction.

[0043] Among them, the continuous probe light emitted by the ultra-narrow linewidth laser source 1 is modulated into pulsed light by an acousto-optic modulator (AOM) 3, and then amplified by the first erbium-doped fiber amplifier (EDFA) 4, and then passed through the first circulator 5 Inject the sensing fiber 6. Th...

Embodiment 2

[0053] At the computer 23, a higher sampling frequency (such as 100MHz) is selected. Obtain the Rayleigh scattering signal S of the ultra-narrow linewidth laser light source 1 from the first acquisition card 20 and the second acquisition card 22 respectively 2 , and the interference detection signal S of the narrow linewidth laser source 10 1 , according to the repetition frequency of the modulation signal of the acousto-optic modulator 3, the Rayleigh scattering signal S 2 Truncate into multiple scatter traces in time order r = {r 1 ,r 2 ,r 3 ,...,r i ,...,r k}.

[0054] In order to realize the location of the vibration event, the improved moving average algorithm is used to reduce the signal noise, and the wavelet information entropy method is used to eliminate the influence of the attenuation along the sensing fiber 6 and quickly and accurately locate the location of the vibration. Specifically include the following processes:

[0055] 101: Average K scattering trac...

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

PUM

No PUM Login to View More

Abstract

The invention discloses a composite optical fiber sensing system and sensing method. The invention has the same positioning accuracy as a phase-sensitive OTDR, and at the same time can obtain high-frequency details of vibration, and then carry out accurate vibration type identification, effectively reducing the system's False alarm rate. Since the phase-sensitive OTDR uses reverse Rayleigh scattered light for detection, the reflected light intensity is extremely low, and the light intensity of the interferometer is high, so the optical signal of the phase-sensitive OTDR is easily submerged in the credit of the interferometer. With the introduction of FBG, the system successfully realizes the optical path combination of interferometer and scatterometer and the separation of optical signals, making the system relatively simple in structure and low in cost. The precise position of the vibration can be obtained by performing the improved moving average algorithm and wavelet information entropy algorithm on the Rayleigh scattering signal of the ultra-narrow linewidth laser source. The interference signal of the narrow-linewidth laser source contains rich frequency information, which can be decomposed by wavelet packets, and the type of vibration can be identified through the neural network, reducing the false alarm rate.

Description

technical field [0001] The invention relates to the field of optical fiber sensing, in particular to a composite optical fiber sensing system and sensing method based on the principles of Bragg grating, Mach-Zehnder interferometer and phase optical time domain reflectometer. Background technique [0002] Due to its high sensitivity, immunity to electromagnetic interference, wide detection range, and low cost, distributed optical fiber sensing systems are widely used in long-distance oil and gas pipeline monitoring, perimeter security, and building structure health monitoring. research hotspots. [0003] The Mach-Zehnder / Sagnac interferometer distributed optical fiber sensing system uses the detection of phase difference changes caused by external disturbances in the two sensing optical paths, and uses the correlation time delay estimation method for positioning, which can sense vibrations well. However, due to the difficulty of determining the time delay in the correlation ...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

Application Information

Patent Timeline
no application Login to View More
Patent Type & Authority Patents(China)
IPC IPC(8): G01H9/00
Inventor 封皓施羿沙洲曾周末靳世久
Owner 天津精仪精测科技有限公司