KR20140101078A - Fiber bragg gratting sensor - Google Patents

Fiber bragg gratting sensor Download PDF

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Publication number
KR20140101078A
KR20140101078A KR1020130014186A KR20130014186A KR20140101078A KR 20140101078 A KR20140101078 A KR 20140101078A KR 1020130014186 A KR1020130014186 A KR 1020130014186A KR 20130014186 A KR20130014186 A KR 20130014186A KR 20140101078 A KR20140101078 A KR 20140101078A
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KR
South Korea
Prior art keywords
sensor
optical fiber
core layer
fbg
fiber bragg
Prior art date
Application number
KR1020130014186A
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Korean (ko)
Inventor
오영기
정동호
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(주)제이엠솔루션
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Publication date
Application filed by (주)제이엠솔루션 filed Critical (주)제이엠솔루션
Priority to KR1020130014186A priority Critical patent/KR20140101078A/en
Publication of KR20140101078A publication Critical patent/KR20140101078A/en

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
    • G01K11/00—Measuring temperature based upon physical or chemical changes not covered by groups G01K3/00, G01K5/00, G01K7/00 or G01K9/00
    • G01K11/32—Measuring temperature based upon physical or chemical changes not covered by groups G01K3/00, G01K5/00, G01K7/00 or G01K9/00 using changes in transmittance, scattering or luminescence in optical fibres
    • G01K11/3206—Measuring temperature based upon physical or chemical changes not covered by groups G01K3/00, G01K5/00, G01K7/00 or G01K9/00 using changes in transmittance, scattering or luminescence in optical fibres at discrete locations in the fibre, e.g. using Bragg scattering
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L1/00—Measuring force or stress, in general
    • G01L1/24—Measuring force or stress, in general by measuring variations of optical properties of material when it is stressed, e.g. by photoelastic stress analysis using infrared, visible light, ultraviolet
    • G01L1/242—Measuring force or stress, in general by measuring variations of optical properties of material when it is stressed, e.g. by photoelastic stress analysis using infrared, visible light, ultraviolet the material being an optical fibre
    • G01L1/246—Measuring force or stress, in general by measuring variations of optical properties of material when it is stressed, e.g. by photoelastic stress analysis using infrared, visible light, ultraviolet the material being an optical fibre using integrated gratings, e.g. Bragg gratings
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L11/00—Measuring steady or quasi-steady pressure of a fluid or a fluent solid material by means not provided for in group G01L7/00 or G01L9/00
    • G01L11/02—Measuring steady or quasi-steady pressure of a fluid or a fluent solid material by means not provided for in group G01L7/00 or G01L9/00 by optical means
    • G01L11/025—Measuring steady or quasi-steady pressure of a fluid or a fluent solid material by means not provided for in group G01L7/00 or G01L9/00 by optical means using a pressure-sensitive optical fibre
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/02—Optical fibres with cladding with or without a coating
    • G02B6/02057—Optical fibres with cladding with or without a coating comprising gratings
    • G02B6/02076—Refractive index modulation gratings, e.g. Bragg gratings

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Optical Transform (AREA)

Abstract

A fiber Bragg grating sensor is disclosed in which the clad layer surrounds a core layer having Bragg gratings. The core layer expands the Bragg gratings located therein using a predetermined method to have a structure wider than a predetermined width. The clad layer surrounds the core layer. According to the present invention, the sensitivity of the fiber bragg grating (FBG) sensor is maximized to improve the resolution of the sensor, thereby more accurately analyzing the physical property change of the measurement object. Also, it is an object of the present invention to provide an optical fiber grating sensor capable of improving sensitivity and resolution as a sensor by using an extended fiber Bragg grating (FBG) sensor to increase the moving width of a wavelength according to external influences.

Description

Fiber Bragg grating sensor

The present invention relates to a fiber grating sensor, and more particularly, to an optical fiber grating sensor designed to maximize the sensitivity of a fiber bragg grating (FBG) sensor to improve the resolution of the sensor.

The fiber optic sensor is durable and does not suffer from corrosion due to no corrosion, and can be multiplexed. Although various measurement sensors are used to analyze the safety of buildings and other structures, the use of optical fiber sensors has been increasingly used as an alternative to conventional measurement systems.

The optical fiber constituting such an optical fiber sensor is generally composed of a fiber core, a cladding, and a jacket for protecting the core and the cladding with different refractive indexes so that the incident light is totally reflected. Optical fiber sensors using these optical fibers can be classified into a single point, a distribution, and a multi-point type according to the measurement range.

In other words, the single-point optical fiber sensor is for measuring the variation of the strain, temperature, and pressure of the portion where the optical fiber sensor is mounted, and is simple. However, when a plurality of portions are targeted, it is necessary to mount the optical fiber sensor in various portions. There may be some limitations. OTDR (Optical Time Domain Reflectometry) is a typical distributed optical fiber sensor. This is advantageous for measuring the overall behavior of a structure using a single optical fiber. A multi-fiber optical fiber sensor is a type in which two or more single-point optical fiber sensors are installed in one optical fiber sensor, and corresponds to an FBG sensor (fiber Bragg grating sensor).

Such an FBG sensor generates a grating by inducing a refractive index change by periodically scanning a laser beam in an ultraviolet region on an optical fiber core to which Ge is added, and an optical element for reflecting light of a specific wavelength determined by the interval of the grating to be. When a broadband spectrum is incident on an optical fiber, the wavelength components satisfying the condition are reflected from the optical fiber grating, and the remaining wavelength components pass through the optical spectrum analyzer.

Fiber Bragg Grating Sensor (FBG), which is currently being used, can be used as a sensor for various fields such as strain sensor, pressure sensor and gas sensor, and has the advantage of using multiple sensors in one strand . In order to improve the sensitivity of FBG sensor (fiber Bragg Grating Sensor), uniform, chirped, and long-period methods are used by changing Bragg and Gratting. However, this causes an excessive cost.

Specifically, the optical fiber grating sensor can be fixed within a short period of time when the optical fiber grating sensor is fixed to the optical axis of the sensor device, Discloses an optical fiber grating sensor fixing structure which is excellent in efficiency and capable of accurate sensing action.

Also, Korean Laid-Open Publication No. 2012-0010296 (entitled " optical fiber grating sensor fixing method and fixing structure thereof ") provides a method of easily fixing an optical fiber grating sensor to a fixture and a fixing structure thereof, Discloses an optical fiber grating sensor fixing method and a fixing structure capable of stably fixing a lattice sensor.

SUMMARY OF THE INVENTION The present invention provides an optical fiber grating sensor capable of improving the resolution of a sensor by maximizing the sensitivity of a fiber bragg grating (FBG) sensor, thereby more accurately analyzing changes in physical characteristics of a measurement object have.

Another object of the present invention is to provide an optical fiber grating sensor capable of improving sensitivity and resolution as a sensor by using an extended fiber Bragg grating (FBG) sensor to increase the moving width of a wavelength according to external influences I have to.

According to an aspect of the present invention, there is provided an optical fiber grating sensor comprising: a fiber Bragg grating (FBG) in which a clad layer surrounds a core layer having Bragg gratings; A core layer having an expanded structure larger than a predetermined width by expanding Bragg gratings located therein; And a clad layer surrounding the core layer.

According to the optical fiber grating sensor of the present invention, the sensitivity of the fiber bragg grating (FBG) sensor can be maximized to improve the resolution of the sensor, thereby more accurately analyzing the physical property change of the measurement object. Also, it is an object of the present invention to provide an optical fiber grating sensor capable of improving sensitivity and resolution as a sensor by using an extended fiber Bragg grating (FBG) sensor to increase the moving width of a wavelength according to external influences.

1 is a view showing the structure of an optical fiber grating sensor (FBG) according to the present invention,
FIG. 2 is an enlarged view of an optical fiber core constituting an optical fiber grating sensor (FBG) according to the present invention,
3 is a cross-sectional view of a fiber grating sensor (FBG) according to the present invention in a vertical direction.

Hereinafter, a preferred embodiment of the optical fiber grating sensor according to the present invention will be described in detail with reference to the accompanying drawings.

1 is a view showing the structure of an optical fiber grating sensor (FBG) according to the present invention. Referring to FIG. 1, the optical fiber grating sensor (FBG) 5 according to the present invention is intended to provide an extended core layer 2 in order to improve the sensitivity of a fiber grating sensor (FBG).

The optical fiber grating sensor (FBG) 5 according to the present invention is characterized by reflecting only a specific wavelength according to the number and width of the bragg grating. Therefore, when a broadband light source 1 is input, a specific wavelength is reflected (4) when passing through the FBG (5), other wavelengths except the reflected wavelength pass (6), and the next optical fiber grating sensor (FBG).

When an external influence is applied to such an optical fiber grating sensor (FBG) 5, the interval of the optical fiber grating sensor (FBG) 5 at a constant interval is changed and the reflected wavelength 4 is moved to another wavelength band. Sensing can be done in the form of sensing. At this time, the input light source should be a broadband light source 1 having the full wavelength as described above.

The optical fiber constituting the optical fiber sensor includes a fiber core layer 2, a cladding layer 3 and a core layer 2 and a cladding layer 3 having different refractive indices so that the incident light is totally reflected. As shown in Fig.

FIG. 2 is an enlarged view of the core layer 2 shown in FIG. 1, and a bragg grating is formed on a core having a constant width. 3 is a view showing a state in which the Bragg grating portion of the core layer 2 is extended. This is a structure which can respond more sensitively to external influences, and is more preferable than a structure of a conventional Bragg grating And has a structure with a wider width.

3, the core layer 2 of the optical fiber grating sensor (FBG) 5 according to the present invention is heated to a high temperature when the optical fiber grating sensor (FBG) 5 is manufactured, And an expanded core layer (7) which expands the core layer (2) by thermal expansion. (FBG) 5 having an extended structure is implemented in the extended core layer 7 using a phase mask, a holographic method, a point-to-point method, or the like.

The extended fiber grating sensor (FBG) 5 has a wider range of wavelengths depending on the external influences, thereby enhancing the resolution and increasing the sensitivity.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is clearly understood that the same is by way of illustration and example only and is not to be taken by way of limitation in the embodiment in which said invention is directed. It will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the scope of the appended claims.

1: broadband source
2: core layer
3: cladding layer
7: extended core layer

Claims (4)

In a fiber Bragg grating (FBG) in which a clad layer surrounds a core layer having Bragg gratings,
A core layer having an expanded structure larger than a predetermined width by expanding Bragg gratings located therein using a predetermined method; And
And a clad layer surrounding the core layer. The method according to claim 1,
Wherein the core layer is made of Si. 3. The method of claim 2,
The predetermined method of the core layer is a high temperature heating method,
Wherein the Si layer is thermally expanded using the high-temperature heating method to expand the width of the core layer. The method according to claim 1,
Wherein the core layer has a diameter of 10 占 퐉 to 12 占 퐉.
KR1020130014186A 2013-02-08 2013-02-08 Fiber bragg gratting sensor KR20140101078A (en)

Priority Applications (1)

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KR1020130014186A KR20140101078A (en) 2013-02-08 2013-02-08 Fiber bragg gratting sensor

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KR1020130014186A KR20140101078A (en) 2013-02-08 2013-02-08 Fiber bragg gratting sensor

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105115440A (en) * 2015-08-19 2015-12-02 华中科技大学 Partial displacement measurement method based on fiber grating sensor
US10012776B2 (en) 2015-11-23 2018-07-03 Microsoft Technology Licensing, Llc Optical filters, methods of manufacture, and methods of use

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105115440A (en) * 2015-08-19 2015-12-02 华中科技大学 Partial displacement measurement method based on fiber grating sensor
CN105115440B (en) * 2015-08-19 2017-09-12 华中科技大学 A kind of local displacement measuring method based on fiber-optic grating sensor
US10012776B2 (en) 2015-11-23 2018-07-03 Microsoft Technology Licensing, Llc Optical filters, methods of manufacture, and methods of use

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