Method and apparatus for sensing methane concentration based on optical fiber Bragg raster

An optical fiber Bragg, methane concentration technology, applied in the coupling of optical waveguides, material analysis by optical means, measurement devices, etc., can solve the problems of affecting measurement accuracy, unfavorable for distributed sensing, complex processing circuits, etc. Solve the effect of being susceptible to electromagnetic interference

Inactive Publication Date: 2007-01-31
ZHEJIANG UNIV
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Problems solved by technology

This method has high measurement accuracy, but the processing circuit is relatively complex, and is easily affected by external electromagnetic interference, which affects the measurement accuracy; moreover, the processing circuit needs power supply, and there is a potential safety hazard of electric sparks
In addition, this method is not conducive to the realization of distributed sensing

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  • Method and apparatus for sensing methane concentration based on optical fiber Bragg raster

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Embodiment Construction

[0016] Such as figure 1 As shown, the broadband light source 1 is connected to the optical signal of the ① end of the optical fiber circulator 2 , and the ② end of the optical fiber circulator 2 is connected to the optical signal of the FBG sensor 3 . The methane catalytic oxidation element 4 is connected with the FBG sensor 3 in position. End ③ of the optical fiber circulator 2 is connected with the optical signal of the optical fiber coupler 5 . The input end of the photodiode 9 is connected with an optical signal at one end of the 3-dB fiber coupler 5 , and the output end of the photodiode 9 is electrically connected with the data acquisition card 10 . The data acquisition card 10 is electrically connected with the FFT analyzer 11 . The other end of the 3-dB fiber optic coupler 5 is respectively connected to the optical signals of two fiber collimators 6, and two mirrors 7 are arranged corresponding to the positions of the two fiber collimators 6, one of which is controll...

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Abstract

The invention relates to a method for optical fiber Prague grating used in methane thickness sensor and the device to realize the method. The FBG sensor connects to broad band light source through optical fiber circulator, and reflecting light connects to optical fiber coupler through optical fiber circulator. The input of photodiode connects to one end of 3-dB optical fiber coupler, and the output end of photodiode connects to data acquisition card that is connected to FFT analyzer. The other end of 3-dB optical fiber coupler connects to two optical fiber collimator. Two reflecting mirrors are set corresponding to two optical fiber collimators and one could control the movement by step motor. The invention is suited for multiple spot methane thickness high accuracy measurement.

Description

technical field [0001] The invention belongs to the technical field of optical fiber sensing, and in particular relates to a method for applying fiber Bragg gratings to methane concentration sensing and equipment for realizing the method. Background technique [0002] In the field of optical fiber sensing, fiber Bragg grating (fiber bragg grating, FBG) has become a very important sensing device in the industry because of its sensitivity to temperature, stress, and refractive index changes. The central wavelength of the FBG reflection spectrum is proportional to the effective refractive index of the fiber core layer, and the effective refractive index of the fiber core layer is affected by the external temperature and stress. Therefore, the change of the central wavelength of the FBG reflection spectrum can be obtained by measuring the change of the central wavelength of the FBG reflection spectrum. Variety. [0003] The traditional catalytic oxidation method uses the methan...

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G02B6/34G01N21/00
Inventor 刘国荣周斌管祖光何赛灵
Owner ZHEJIANG UNIV
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