Method and system for measuring concentration of chemical solution by fiber bragg gratings (FBG)

A fiber grating and chemical solution technology, applied in color/spectral characteristic measurement, measurement devices, material analysis through optical means, etc., can solve problems such as high risk and impossibility, and achieve high safety and accurate measurement results , the effect of reducing the impact

CN102706825AInactive Publication Date: 2012-10-03东北大学秦皇岛分校
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Publication Date
2012-10-03
Estimated Expiration
Not applicable · inactive patent

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Abstract

The invention discloses a method and system for measuring the concentration of a chemical solution by fiber bragg gratings (FBG). The system comprises a broadband light source 1, a fiber isolator 12, a coupler 2, an FBG sensor 3, a spectrum analyzer 4 and a computer control end 5, wherein the fiber isolator 12 is respectively connected with the broadband light source 1 and a coupler 2, the coupler 2 is respectively connected with the FBG sensor 3 and the spectrum analyzer 4, and the spectrum analyzer 4 is connected with the computer control end 5. According to the invention, a double FBG single-end photoetching method is used to reduce the radius of claddings or fiber cores of fiber bragg gratings, so as to obtain a double fiber bragg grating structure which is sensitive to the external refractive index, and thus the FBG sensor is formed so that the FBG propagation mode is sensitive to the change of concentration of a solution outside, and therefore the on-ling and real-time acquisition and remote control for the concentration of the solution can be realized through detection on the change of reflection wavelength of fiber bragg gratings under the support of equipment such as the coupler, the FBG sensor, the spectrum analyzer.
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Description

[0001] technical field

[0002] The invention relates to a method and system for measuring the concentration of a chemical solution by using an optical fiber grating, and belongs to the technical field of concentration measurement of the chemical solution. Background technique

[0003] Concentration is one of the main parameters to characterize the characteristics of a solution, and it is also an important measurement parameter in industrial and agricultural production and scientific research experiments. Many physical and chemical properties of substances are easily affected by concentration, and the quality of the product will be affected if the concentration is too high or too low. The traditional concentration measurement method is susceptible to electromagnetic interference and has a complex structure, which cannot meet the requirements of high-precision online measurement in places such as flammable, explosive, and corrosive.

[0004] In recent years, long-period fibe...

Examples

Embodiment 1

[0034] Embodiment 1 of the present invention: a kind of method utilizing optical fiber grating to measure chemical solution concentration, comprises the following steps:

[0035] S1, the broadband light enters the coupler through the fiber isolator for separation;

[0036] S2, using double FBG single-ended photolithography to reduce the cladding or core radius of the fiber grating to form a FBG sensor; the evanescent field of light wave is transmitted from the FBG sensor to directly interact with the solution, and the reflected light is input to the spectrum analyzer;

[0037] S3, the spectrum analyzer analyzes and measures the change information of the fiber grating wavelength, and sends the data information to the remote control terminal for demodulation, analysis and processing, so as to realize the real-time collection of the solution concentration.

[0038] In step S2, the double-FBG single-ended lithography method refers to first placing the sensitive grating on a preci...

Embodiment 2

[0055] Embodiment 2: a kind of method utilizing optical fiber grating to measure chemical solution concentration, comprises the following steps:

[0056] S1, the broadband light enters the coupler through the fiber isolator for separation;

[0057] S2, using double FBG single-ended photolithography to reduce the cladding or core radius of the fiber grating to form a FBG sensor; the evanescent field of light wave is transmitted from the FBG sensor to directly interact with the solution, and the reflected light is input to the spectrum analyzer;

[0058] S3, the spectrum analyzer analyzes and measures the change information of the fiber grating wavelength, and sends the data information to the remote control terminal for demodulation, analysis and processing, so as to realize the real-time collection of the solution concentration.

[0059]A system for measuring the concentration of a chemical solution using an optical fiber grating to achieve the above method, comprising: a bro...

Embodiment 3

[0060] Embodiment 3: a kind of method utilizing optical fiber grating to measure chemical solution concentration, comprises the following steps:

[0061] S1, the broadband light enters the coupler through the fiber isolator for separation;

[0062] S2, using double FBG single-ended photolithography to reduce the cladding or core radius of the fiber grating to form a FBG sensor; the evanescent field of light wave is transmitted from the FBG sensor to directly interact with the solution, and the reflected light is input to the spectrum analyzer;

[0063] S3, the spectrum analyzer analyzes and measures the change information of the fiber grating wavelength, and sends the data information to the remote control terminal for demodulation, analysis and processing, so as to realize the real-time collection of the solution concentration.

[0064] A system for measuring the concentration of a chemical solution using an optical fiber grating to realize the above method, comprising: a br...