BOTDA (Brillouin Optical Time-Domain Analysis) system based on pulse coding and coherent detection

A pulse encoding and encoding technology, applied in the field of BOTDA system, can solve the problems of insufficient signal-to-noise ratio and spatial resolution measurement accuracy, and achieve the effects of enhanced adaptability and practicability, long sensing distance and high measurement accuracy

Inactive Publication Date: 2013-08-14
NANJING UNIV +1
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Problems solved by technology

However, the system suffers from insufficient signal-to-

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  • BOTDA (Brillouin Optical Time-Domain Analysis) system based on pulse coding and coherent detection
  • BOTDA (Brillouin Optical Time-Domain Analysis) system based on pulse coding and coherent detection
  • BOTDA (Brillouin Optical Time-Domain Analysis) system based on pulse coding and coherent detection

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Embodiment Construction

[0021] The technical solutions of the present invention will be further described and described in detail below in conjunction with the accompanying drawings and embodiments.

[0022] like figure 1 As shown, a BOTDA system based on pulse encoding and coherent detection includes a frequency shifter 9, a narrow linewidth laser 10, a first polarization maintaining coupler 11, a first polarization maintaining coupler, a first electro-optic modulator 13, a pulse signal Source 14, second electro-optic modulator 12, polarization scrambler 16, microwave signal source 17, test fiber 18, optical circulator 19, 3dB coupler 20, balanced photodetector 21, spectrum analyzer 22 and digital signal processing unit 23 .

[0023] Assume that the frequency of the light emitted by the narrow-linewidth laser 10 with a 3dB linewidth of less than 1 MHz is f 0 , the continuous light emitted by the laser is divided into two continuous light paths by the first polarization-maintaining coupler 11: the ...

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Abstract

A BOTDA system based on pulse coding and coherent detection comprises a narrow linewidth laser device (10), a first polarization-maintaining coupler (11), a second polarization-maintaining coupler (12), a microwave signal source (17), testing optical fibers (18), an optical circulator (19), a 3dB coupler (20), a balance photoelectric detector (21), a scrambler (16), a spectrum analyzer (22) and a digital signal processing unit (23), wherein continuous light emitted by the arrow linewidth laser device (10) is divided into two channels of continuous light, namely, a first channel of the continuous light and a second channel of the continuous light, through the first polarization-maintaining coupler (11); and the system further comprises a frequency shifter (9), a first electrooptical modulator (13), a pulse signal source (14) and a second electrooptical modulator (15). The system adopts a pulse coding technology and a coherent detection method, so that the signal to noise ratio of the BOTDA and the measurement accuracy can be improved, the sensing distance is increased, and the system has the function of breakpoint detection.

Description

technical field [0001] The invention relates to a BOTDA system based on pulse coding and coherent detection, belonging to the technical field of distributed optical fiber sensing. Background technique [0002] Brillouin Optical Time-Domain Analysis (BOTDA) based on optical fiber stimulated Brillouin scattering is a sensing technology with long-distance, high measurement accuracy temperature and strain measurement capabilities among many distributed optical fiber sensors , has great potential use in structural health monitoring of large civil engineering, communication optical cables, oil and gas pipelines, etc. In this technology, when the frequency difference of two beams of light waves propagating oppositely in the optical fiber is within the range of Brillouin gain, they undergo stimulated Brillouin interaction through the acoustic wave field, thereby energy transfer occurs between the two beams of light, When the frequency difference between the two beams of light is eq...

Claims

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Application Information

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IPC IPC(8): G01D5/353
Inventor 张旭苹胡君辉夏岚郭经红梁云李炳林
Owner NANJING UNIV
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