CN106802160A - A kind of Demodulation System for Fiber Bragg and demodulation method based on fork-shaped interference pattern - Google Patents
A kind of Demodulation System for Fiber Bragg and demodulation method based on fork-shaped interference pattern Download PDFInfo
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- G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
- G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
- G01D5/26—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light
- G01D5/32—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light
- G01D5/34—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells
- G01D5/353—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells influencing the transmission properties of an optical fibre
- G01D5/35303—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells influencing the transmission properties of an optical fibre using a reference fibre, e.g. interferometric devices
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- G01D5/32—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light
- G01D5/34—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells
- G01D5/353—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells influencing the transmission properties of an optical fibre
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Abstract
The present invention proposes a kind of Demodulation System for Fiber Bragg and demodulation method based on fork-shaped interference pattern, including reference path and optical path composition, and Gaussian beam is produced in reference path；Fiber grating is introduced in optical path, produces the light beam with orbital angular momentum, the light in reference path and optical path to be interfered at beam-splitter by spiral phase plate, produce fork-shaped interference pattern.When extraneous change to be measured, propagation of the light in fiber grating can produce phase delay, the phase difference between reference path and optical path is caused to change, fork-shaped interference pattern is set to be moved at bifurcation, by CCD camera real-time detection and the change of fork-shaped interference pattern is recorded, finally draw extraneous corresponding relation to be measured and between fork-shaped interference pattern.The present invention carries out signal demodulation without traditional optical instrument spectral instrument etc., reduces the cost of sensor-based system, and fiber grating will be made to be applied to more engineering fields.
Description
Technical field
The present invention relates to a kind of Demodulation System for Fiber Bragg and demodulation method based on fork-shaped interference pattern, belong to light
Electro-detection technology field.
Background technology
With the rise of internet and technology of Internet of things, for the requirement more and more higher of sensor, the development of sensor with
Based on sensitive, high accuracy, small volume and intellectuality.Traditional sensor is in these emerging application field high temperature high voltage resistant characteristics
Differ from, easily receive electromagnetic interference, and fiber-optic grating sensor has high sensitivity, light, distribution as a kind of novel sensor
The advantages of formula measurement, electromagnetism interference, it is highly suitable for the fields such as architectural engineering, Aero-Space, biomedicine, power system.
The many advantages that fiber-optic grating sensor has can apply the occasion not applied in traditional sensors, be moment sensor technology
Study hotspot, and the key technology of fiber-optic grating sensor is the design of demodulating system.At present to fiber grating sensing signal
Demodulation generally use optical instrument spectrometer, but because its volume is big, expensive, sweep speed it is slow, use condition is harsh, no
Suitable for practical engineering application.It is therefore proposed that it is a kind of have industrial application value, low cost, can be portable optical fiber grating sensing solution
Tune method is significant.
The content of the invention
The purpose of the present invention is the weak point for overcoming existing optical fiber grating sensing signal demodulation method, proposes that one kind has
Practical engineering application value optical fiber grating sensing signal demodulation system and demodulation method, meet high accuracy, can portable, low cost
Demand.
It is adopted the following technical scheme that：A kind of Demodulation System for Fiber Bragg based on fork-shaped interference pattern, including：
Laser for producing light beam；
Light beam for that will inject carries out the coupler of light splitting, and the light beam that the laser sends injects the coupler；
Light beam for that will inject is converted into the optical path of the light beam with orbital angular momentum；
Light beam for that will inject is converted into the reference path of Gaussian beam, and the light beam after the coupler light splitting is penetrated respectively
Enter the reference path and the optical path；
Beam-splitter for producing fork-shaped interfering beam, the light beam in the reference path and the optical path injects institute
State in beam-splitter and interfere；
For by fork-shaped interfering beam real-time detection and being recorded as the CCD camera of fork-shaped interference pattern signal, the CCD phases
Machine receives the fork-shaped interfering beam that the beam-splitter is injected；
The optical path includes fiber grating, first collimator, spiral phase plate and speculum successively；
The reference path includes the second collimater.
Further, the laser is distributed feedback laser, and the coupler is single-mode optical-fibre coupler, described
Light beam in reference path is conducted by single-mode fiber, and the light beam that the first collimator and second collimater will be injected turns
Directional light is turned to, the collimated light beam of input is converted into orbital angular momentum light beam and exported, the reflection by the spiral phase plate
Beam-splitter described in the orbital angular momentum light beam directive that the direction of propagation that mirror changes light exports the speculum.
Present invention also offers a kind of fiber grating sensing demodulation method based on fork-shaped interference pattern, including described base
It is further comprising the steps of in the Demodulation System for Fiber Bragg of fork-shaped interference pattern：
S1：Laser produces light beam to inject coupler；
S2：Light beam after the coupler light splitting injects optical path and reference path respectively；
S3：Light beam is converted into the light beam with orbital angular momentum by the optical path, and light beam is by the reference light
Road is converted into Gaussian beam, and light beam and Gaussian beam with orbital angular momentum are injected in beam-splitter and interfere to form fork respectively
Shape interfering beam；
S4：The fork-shaped interfering beam that CCD camera projects the beam-splitter is converted into fork-shaped interference pattern signal；
S5：The external world is to be measured to change, and propagation of the light beam in the fiber grating produces phase delay, causes measurement
Phase difference between the Gaussian beam that the light beam with orbital angular momentum and reference path that light path is projected are projected changes, and pitches
Shape interference pattern is moved at bifurcation, constantly passes through CCD camera real-time detection and exports fork-shaped interference pattern signal extremely
Computer 7；
S6：Computer 7 records fork-shaped interference pattern signal, obtains corresponding between the extraneous interference pattern with fork-shaped to be measured
Relation.
Further, the length of the fiber grating be 0.16mm, screen periods be 0.529 μm, fiber core refractive index be
1.4681st, cladding index is 1.4628 and largest refractive index difference is 0.0053.
Further, the laser is distributed feedback laser, and the coupler is single-mode optical-fibre coupler, described
Light beam in reference path is conducted by single-mode fiber, and the light beam that the first collimator and second collimater will be injected turns
Directional light is turned to, the collimated light beam of input is converted into orbital angular momentum light beam and exported, the reflection by the spiral phase plate
Beam-splitter described in the orbital angular momentum light beam directive that the direction of propagation that mirror changes light exports the speculum.
Further, the laser center wavelength is 1550nm, and the coupler is splitting ratio 1:1 and operation wavelength be
2 × 2 single-mode optical-fibre couplers of 1550nm；
The core diameter of the single-mode fiber in the reference path is 9 μm；
Transmitting beam in optical fiber is converted into dispersion angle and is no more than by the first collimator and second collimater
2 ° of directional light；
Work for the collimated light beam of input to be converted into orbital angular momentum light beam and the spiral phase plate for exporting
Wavelength is 1550nm；
The reflectivity of the speculum for changing the direction of propagation of light is higher than 85%；
The transflection ratio of the beam-splitter is 1:1.
The invention has the advantages that：
(1) a kind of Demodulation System for Fiber Bragg based on fork-shaped interference pattern of the invention, can realize to external world
Measurement to be measured, using this programme realize the demodulation of fiber grating sensing signal than traditional wavelength demodulation method small volume, into
This is low, is more suitable for practical engineering application；
(2) a kind of fiber grating sensing demodulation method based on fork-shaped interference pattern of the invention, using fiber grating
Light delay characteristic, can cause propagation of the light in fiber grating to produce different phase delays when extraneous change to be measured, enter
One step strengthens the interference effect between reference path and optical path, and this programme can be used for small size, highly sensitive various
In fiber bragg grating device；
(3) a kind of fiber grating sensing demodulation method based on fork-shaped interference pattern of the invention, by introducing track angle
Momentum light beam and adjustment light source, signal receiving device etc. improve the performance of measuring system, solve traditional wavelength demodulation method
Spectrometer resolving power is limited, causes its certainty of measurement and the limited problem of range of application；
(4) a kind of fiber grating sensing demodulation method based on fork-shaped interference pattern of the invention, only needs during use
Ensure the stability of whole device, without special technique compared with other method, reduce Process Exploration difficulty.
Brief description of the drawings
In order to illustrate more clearly of the embodiment of the present application or technical scheme of the prior art, below will be to embodiment or existing
The accompanying drawing to be used needed for having technology description is briefly described.It should be evident that drawings in the following description are only this
Some embodiments described in application, for those of ordinary skill in the art, on the premise of not paying creative work,
Other accompanying drawings can also be obtained according to these accompanying drawings；
Fig. 1 is the structure of the Demodulation System for Fiber Bragg based on fork-shaped interference pattern of the present invention and demodulation method
Schematic diagram；
Fig. 2 (a) is interference pattern when reference path and optical path phase difference are 0；Fig. 2 (b) is reference path and survey
Interference pattern when amount light path phase difference is pi/2；Fig. 2 (c) is interference pattern when reference path and optical path phase difference are π
Sample；
Fig. 3 (a) is 1 row amplitude variations situation of fork-shaped interference pattern bifurcation left side；Fig. 3 (b) is fork-shaped interference pattern point
1 row amplitude variations situation of crunode right side, different curves represent the amplitude point of reference path and optical path under out of phase difference
Cloth situation；
Fig. 4 (a) is the corresponding relation of reference path and optical path phase difference and amplitude；Fig. 4 (b) is reference path and survey
Measure the corresponding relation after light path phase difference makes the difference with bifurcation both sides amplitude.
Wherein：1st, optical path, 2, reference path, 3, laser, 4, coupler, 5, beam-splitter, 6, CCD camera, 11, light
Fine grating, 12, first collimator, 13, spiral phase plate, 14, speculum, the 21, second collimater.
Specific embodiment
To make technical scheme and advantage clearer, with reference to the accompanying drawing in the embodiment of the present invention, to this
Technical scheme in inventive embodiments carries out clearly complete description.
Embodiment 1
A kind of Demodulation System for Fiber Bragg based on fork-shaped interference pattern, including：
Laser 3 for producing light beam；
Light beam for that will inject carries out the coupler 4 of light splitting, and the light beam that the laser 3 sends injects the coupler
4；
Light beam for that will inject is converted into the optical path 1 of the light beam with orbital angular momentum；
Light beam for that will inject is converted into the reference path 2 of Gaussian beam, the light beam difference after the light splitting of the coupler 4
Inject the reference path 2 and the optical path 1；
Beam-splitter 5 for producing fork-shaped interfering beam, the light beam in the reference path 2 and the optical path 1
Enter and interfered in the beam-splitter 5；
For by fork-shaped interfering beam real-time detection and being recorded as the CCD camera 6 of fork-shaped interference pattern signal, the CCD
Camera 6 receives the fork-shaped interfering beam that the beam-splitter 5 is injected；
The optical path 1 includes fiber grating 11, first collimator 12, spiral phase plate 13 and speculum 14 successively；
The reference path 2 includes the second collimater 21.
Further, the laser 3 is distributed feedback laser, and the coupler 4 is single-mode optical-fibre coupler, institute
The light beam stated in reference path 2 is conducted by single-mode fiber, and the first collimator 12 and second collimater 21 will be injected
Light beam be converted into directional light, the collimated light beam of input is converted into orbital angular momentum light beam and defeated by the spiral phase plate 13
Go out, divide described in the orbital angular momentum light beam directive that the direction of propagation that the speculum 14 changes light exports the speculum 14
Tabula rasa 5.
Heretofore described CCD camera 6 is charge-coupled device camera.
Gaussian beam is produced in the reference path 2；The fiber grating 11, light beam warp are provided with the optical path 1
Cross the spiral phase plate 13 and be converted into the light beam with orbital angular momentum, in the reference path 2 and the optical path 1
Light beam is interfered in the beam-splitter 5, produces fork-shaped interfering beam, when the external world's (such as temperature, strain) change to be measured
When, propagation of the light beam in the fiber grating 11 can produce phase delay, cause the reference path 2 and the optical path
Phase difference between 1 changes, and fork-shaped interfering beam is moved at bifurcation, by the CCD camera 6 by fork-shaped
The change real-time detection of interfering beam is simultaneously recorded as the change of fork-shaped interference pattern, finally draws extraneous to be measured with fork-shaped interference
Corresponding relation between pattern, orbital angular momentum light beam is introduced on the basis of Mach-Zehnder interferometer and changes light source, signal
Reception device, so as to substitute the Wavelength demodulation method of traditional fiber grating sensing use i.e. by the movement of resonance wavelength on spectrometer
To realize measurement to be measured to external world.
Embodiment 2
Present invention also offers a kind of fiber grating sensing demodulation method based on fork-shaped interference pattern, including described base
It is further comprising the steps of in the Demodulation System for Fiber Bragg of fork-shaped interference pattern：
S1：Laser 3 produces light beam to inject coupler 4；
S2：Light beam after the light splitting of the coupler 4 injects optical path 1 and reference path 2 respectively；
S3：Light beam is converted into the light beam with orbital angular momentum by the optical path 1, and light beam is by the reference light
Road 2 is converted into Gaussian beam, and light beam and Gaussian beam with orbital angular momentum are injected interfere to be formed in beam-splitter 5 respectively
Fork-shaped interfering beam；
S4：The fork-shaped interfering beam that CCD camera 6 projects the beam-splitter 5 is converted into fork-shaped interference pattern signal；
S5：The external world is to be measured to change, and propagation of the light beam in the fiber grating 11 produces phase delay, causes to survey
Phase difference between the Gaussian beam that the light beam with orbital angular momentum and reference path 2 that amount light path 1 is projected are projected becomes
Change, fork-shaped interference pattern is moved at bifurcation, constantly pass through the real-time detection of CCD camera 6 and export fork-shaped interference pattern
Signal is to computer 7；
S6：Computer 7 records fork-shaped interference pattern signal, obtains corresponding between the extraneous interference pattern with fork-shaped to be measured
Relation.
Further, the length of the fiber grating 11 be 0.16mm, screen periods be 0.529 μm, fiber core refractive index be
1.4681st, cladding index is 1.4628 and largest refractive index difference is 0.0053.
Further, the laser 3 is distributed feedback laser, and the coupler 4 is single-mode optical-fibre coupler, institute
The light beam stated in reference path 2 is conducted by single-mode fiber, and the first collimator 12 and second collimater 21 will be injected
Light beam be converted into directional light, the collimated light beam of input is converted into orbital angular momentum light beam and defeated by the spiral phase plate 13
Go out, divide described in the orbital angular momentum light beam directive that the direction of propagation that the speculum 14 changes light exports the speculum 14
Tabula rasa 5.
Further, the centre wavelength of the laser 3 is 1550nm, and the coupler 4 is splitting ratio 1:1 and operation wavelength
It is 2 × 2 single-mode optical-fibre couplers of 1550nm；
The core diameter of the single-mode fiber in the reference path 2 is 9 μm；
Transmitting beam in optical fiber is converted into dispersion angle not by the first collimator 12 and second collimater 21
Directional light more than 2 °；
Work for the collimated light beam of input to be converted into orbital angular momentum light beam and the spiral phase plate for exporting
Wavelength is 1550nm；
The reflectivity of the speculum 14 for changing the direction of propagation of light is higher than 85%；
The transflection ratio of the beam-splitter 5 is 1:1.
Embodiment 3
The present invention proposes a kind of Demodulation System for Fiber Bragg and demodulation method based on fork-shaped interference pattern, and studies
The fundamental characteristics of the Demodulation System for Fiber Bragg and demodulation method based on fork-shaped interference pattern, including reference path
2 and optical path 1, produce Gaussian beam in the reference path 2；The fiber grating is injected in the optical path 1
11, then produce the light beam with orbital angular momentum, the reference path 2 and the measurement light by the spiral phase plate 13
Light beam in road 1 is interfered at the beam-splitter 5, produces fork-shaped interference pattern.When the external world's (such as temperature, strain to be measured
Deng) change when, propagation of the light beam in the fiber grating 11 can produce phase delay, cause the reference path 2 and described
Phase difference between optical path 1 changes, and fork-shaped interference pattern is moved at bifurcation, by the CCD phases
The real-time detection of machine 6 simultaneously records the change of fork-shaped interference pattern, and what is finally gone out between the extraneous interference pattern with fork-shaped to be measured is corresponding
Relation.
In such scheme, optical fiber grating structure is used in the optical path 1, what is utilized is the light of the fiber grating 11
Lag characteristic, rather than the wavelength mobile message of its reflectance spectrum.Known by fiber grating operation principle, when a branch of broad band light wave exists
When being transmitted in grating, incident light can be reflected back in corresponding frequency, and its remaining light will be unaffected saturating from the grating other end
Project.This programme exactly using the transmittance of fiber grating, is less than under conditions of 15%, using optical fiber in fiber grating reflectivity
Grating light delay characteristic produces different phase delays.Research shows that the fiber grating 11 is imitated with good light delay
Really, up to picosecond magnitude.When extraneous change to be measured, propagation of the light beam in the fiber grating 11 will postpone,
And then cause the phase difference between the reference path 2 and the optical path 1 to change.The length of the fiber grating 11 is
0.16mm, screen periods are 0.529 μm, and fiber core refractive index is 1.4681, and cladding index is 1.4628, and largest refractive index difference is
0.0053。
In such scheme, the fork-shaped interference pattern is different from common interference pattern, and it is due to introducing track angular motion
Measure light beam and make interference pattern that fork configuration is presented, so that realize being combined orbital angular momentum with light sensing, using the CCD
The change of the real-time detection fork-shaped interference pattern of camera 6, extracts the change information at interference pattern bifurcation, so as to effectively instead of
Detect that the change information of resonance wavelength is Wavelength demodulation method with spectrometer in conventional method, realize a kind of new signal demodulation side
Method.Described CCD camera model Digital CamIR1550, ultimate resolution is 1296 × 964.
In such scheme, the laser 3 is the distributed feedback laser of 100kHz line widths, and wherein cardiac wave is a length of
1550nm.The coupler 4 is 2 × 2 single-mode optical-fibre couplers, its splitting ratio 1:1, operation wavelength is 1550nm.The reference
Optical fiber used is single-mode fiber in light path 2, and core diameter is 9 μm.The collimater 21 of first collimator 12 and second is by the transmission in optical fiber
Light becomes directional light, and dispersion angle is no more than 2 °.The spiral phase plate 13 is that the collimated light beam of input is converted into track angle
Momentum light beam and export, operation wavelength is 1550nm.The speculum 14 changes the direction of propagation of light, and its reflectivity is higher than
85%.The beam-splitter 5 is NPCH-20-15500 type beam-splitters, and transflection ratio is 1:1.
It is as shown in Figure 1 the principle signal of Demodulation System for Fiber Bragg and demodulation method based on fork-shaped interference pattern
Figure.The light beam that the laser 3 sends is the light of two beam independences by 4 points of the coupler, wherein a branch of optically coupling to carrying
In the optical path 1 of the fiber grating 11, collimated light beam is sent through the first collimator 12, incide the helical phase
The light beam with orbital angular momentum is produced in plate 13；Another beam is produced optically coupling in the reference path 2 with single-mode fiber
Raw Gaussian beam, two-beam is interfered at the beam-splitter 5, produces fork-shaped interference pattern.To make measurement result more adduction
Reason, need to be placed in environment to be measured simultaneously by single-mode fiber part in the part of fiber grating 11 described in optical path and reference path
In, the delay of such two-way light only will be influenceed by the characteristic of the fiber grating 11, and unrelated with optical fiber self character.When outer
Boundary is to be measured when changing, and propagation of the light beam in the fiber grating 11 can make its phase produce delay, and then make difference
Phase difference is produced between light beam by the reference path 2 and the optical path 1, causes fork-shaped interference pattern to move
Dynamic, the change of the real-time detection fork-shaped interference pattern of the CCD camera 6 finally, the CCD camera is stored by the computer 7
The data of 6 collections, draw extraneous corresponding relation to be measured and between fork-shaped interference pattern, so as to realize the solution of transducing signal
Adjust.
Fig. 2 is the interference pattern of the reference path 2 and the optical path 1 under out of phase difference.By Fig. 2 (a) extremely
C () understands that with the increase of phase difference, interference pattern bifurcation constantly moves right, and bifurcation both sides amplitude is continually changing.For
It is accurate to extract the information to be measured that interference pattern is included, this programme using image processing techniques to interference pattern bifurcation at
The amplitude information of both sides is extracted, and interference pattern information is read with imread functions in matlab tool boxes, and to interference
Pattern carries out the treatment such as image enhaucament, filtering and reduces image procossing error.(light is now measured on the basis of at Fig. 2 (a) bifurcations
Phase difference is 0), two side datas at bifurcation to be extracted, and draw both sides number with matlab between road 1 and reference path 2
According to amplitude curve.For the interference image information that guarantee is extracted is clearly accurate, by difference column information in both sides at bifurcation
Extracted repeatedly, by comparative analysis, shown at bifurcation or so that when respectively returning 40 row, both sides shake at the bifurcation for extracting
Width information change rule, it is easy to process and have preferable result, analysis result is as shown in Figure 3.From the figure 3, it may be seen that interference pattern point
Crunode both sides amplitude change have certain symmetry, in figure curve from bottom to top, with the increase of phase difference, amplitude width
Value gradually increases.In order to reduce measurement error, when the reference path 2 and the timing of 1 phase difference of the optical path one, area is chosen
The average value of amplitude is used as amplitude in domain, determines phase difference between the reference path 2 and the optical path 1 and shakes
Relation between amplitude.
Fig. 4 (a) is shaking for the fork-shaped interference pattern of the reference path 2 and the optical path 1 under out of phase difference
Amplitude situation of change, two curves are illustrated respectively in fork-shaped interference pattern bifurcation both sides amplitude variations situation in figure.To calculate
The relation between phase difference and amplitude between the reference path 2 and the optical path 1, this programme is by bifurcation or so
The amplitude of both sides is accordingly made the difference as shown in Fig. 4 (b).Known by Fig. 4 (b), the phase of the reference path 2 and the optical path 1
It is approximately linear relationship between potential difference and amplitude, the linearity is up to 0.9988.Analyzed according to more than, one kind proposed by the present invention is based on
The fiber grating sensing demodulation method of fork-shaped interference pattern changes the signal demodulation structure of traditional fiber grating, solves tradition
Because using the limited problem of spectrometer resolving power, more practical engineering application value in measurement process.
By adopting the above-described technical solution, a kind of optical fiber grating sensing based on fork-shaped interference pattern that the present invention is provided
Demodulating system and demodulation method, can realize measurement to be measured to external world, and fiber grating sensing signal is realized using this programme
Demodulation than traditional wavelength demodulation method small volume, low cost, be more suitable for practical engineering application；Light using fiber grating prolongs
Slow characteristic, can cause propagation of the light in fiber grating to produce different phase delays, further when extraneous change to be measured
Strengthen the interference effect between reference path and optical path, this programme can be used for small size, highly sensitive various optical fiber
In grating device；Improve measuring system by introducing orbital angular momentum light beam and adjustment light source, signal receiving device etc.
Performance, solves that traditional wavelength demodulation method spectrometer resolving power is limited, causes its certainty of measurement and the limited problem of range of application；
The stability of whole device need to only be ensured during use, without special technique compared with other method, technique spy is reduced
Rope difficulty.
The above, the only present invention preferably specific embodiment, but protection scope of the present invention is not limited thereto,
Any one skilled in the art the invention discloses technical scope in, technology according to the present invention scheme and its
Inventive concept is subject to equivalent or change, should all be included within the scope of the present invention.
Claims (6)
1. a kind of Demodulation System for Fiber Bragg based on fork-shaped interference pattern, it is characterised in that including：
Laser for producing light beam；
Light beam for that will inject carries out the coupler of light splitting, and the light beam that the laser sends injects the coupler；
Light beam for that will inject is converted into the optical path of the light beam with orbital angular momentum；
Light beam for that will inject is converted into the reference path of Gaussian beam, and the light beam after the coupler light splitting injects institute respectively
State reference path and the optical path；
Beam-splitter for producing fork-shaped interfering beam, the light beam in the reference path and the optical path injects described point
Interfered in tabula rasa；
For by fork-shaped interfering beam real-time detection and being recorded as the CCD camera of fork-shaped interference pattern signal, the CCD camera connects
Receive the fork-shaped interfering beam that the beam-splitter is injected；
The optical path includes fiber grating, first collimator, spiral phase plate and speculum successively；
The reference path includes the second collimater.
2. the Demodulation System for Fiber Bragg based on fork-shaped interference pattern according to claim 1, is further characterized in that：
The laser is distributed feedback laser, and the coupler is single-mode optical-fibre coupler, the light beam in the reference path
Conducted by single-mode fiber, the light beam that the first collimator and second collimater will be injected is converted into directional light, described
The collimated light beam of input is converted into orbital angular momentum light beam and exported by spiral phase plate, and the speculum changes the propagation of light
Beam-splitter described in the orbital angular momentum light beam directive that direction exports the speculum.
3. a kind of fiber grating sensing demodulation method based on fork-shaped interference pattern, it is characterised in that：Including described in claim 1
The Demodulation System for Fiber Bragg based on fork-shaped interference pattern, it is further comprising the steps of：
S1：Laser produces light beam to inject coupler；
S2：Light beam after the coupler light splitting injects optical path and reference path respectively；
S3：Light beam is converted into the light beam with orbital angular momentum by the optical path, and light beam turns by the reference path
Turn to Gaussian beam, light beam and Gaussian beam with orbital angular momentum inject respectively in beam-splitter interfere to be formed fork-shaped do
Relate to light beam；
S4：The fork-shaped interfering beam that CCD camera projects the beam-splitter is converted into fork-shaped interference pattern signal；
S5：The external world is to be measured to change, and propagation of the light beam in the fiber grating produces phase delay, causes optical path
Phase difference between the Gaussian beam that the light beam with orbital angular momentum and reference path for projecting are projected changes, and fork-shaped is done
Relate to pattern to be moved at bifurcation, constantly pass through CCD camera real-time detection and export fork-shaped interference pattern signal to calculating
Machine 7；
S6：Computer 7 records fork-shaped interference pattern signal, obtains the corresponding pass between the extraneous interference pattern with fork-shaped to be measured
System.
4. a kind of fiber grating sensing demodulation method based on fork-shaped interference pattern according to claim 3, its feature is also
It is：The length of the fiber grating is 0.16mm, screen periods are 0.529 μm, fiber core refractive index is 1.4681, clad refractive
Rate is 1.4628 and largest refractive index difference is 0.0053.
5. a kind of fiber grating sensing demodulation method based on fork-shaped interference pattern according to claim 3, its feature is also
It is：The laser is distributed feedback laser, and the coupler is single-mode optical-fibre coupler, in the reference path
Light beam is conducted by single-mode fiber, and the light beam that the first collimator and second collimater will be injected is converted into directional light,
The collimated light beam of input is converted into orbital angular momentum light beam and exported by the spiral phase plate, and the speculum changes light
Beam-splitter described in the orbital angular momentum light beam directive that the direction of propagation exports the speculum.
6. a kind of fiber grating sensing demodulation method based on fork-shaped interference pattern according to claim 5, its feature is also
It is：The laser center wavelength is 1550nm, and the coupler is splitting ratio 1:1 and operation wavelength for 1550nm 2 × 2
Single-mode optical-fibre coupler；
The core diameter of the single-mode fiber in the reference path is 9 μm；
Transmitting beam in optical fiber is converted into dispersion angle and is no more than 2 ° by the first collimator and second collimater
Directional light；
Operation wavelength for the collimated light beam of input to be converted into orbital angular momentum light beam and the spiral phase plate for exporting
It is 1550nm；
The reflectivity of the speculum for changing the direction of propagation of light is higher than 85%；
The transflection ratio of the beam-splitter is 1:1.
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Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107707300A (en) * | 2017-09-26 | 2018-02-16 | 南京邮电大学 | A kind of method of the non-aligned OAM multiplex systems crosstalk of suppression based on RVP modulation |
| CN108645431A (en) * | 2018-05-30 | 2018-10-12 | 西安工业大学 | A kind of fitting Peak Search Method for the long correlation demodulation of optical fiber Fabry-Perot sensor chamber |
| CN108827344A (en) * | 2018-07-20 | 2018-11-16 | 任元 | A kind of gyroscopic effect verifying device of wave-particle vortex gyro |
| CN111238634A (en) * | 2020-02-17 | 2020-06-05 | 北京理工大学 | Light beam orbital angular momentum spectrum analysis method and device based on interference |
| CN114140383A (en) * | 2021-10-25 | 2022-03-04 | 深圳大学 | Sensing demodulation method for orbital angular momentum mode |
| CN114964328A (en) * | 2022-05-10 | 2022-08-30 | 南京师范大学 | All-fiber angular momentum interference sensing measurement system and method based on spiral grating |
| WO2023070855A1 (en) * | 2021-10-25 | 2023-05-04 | 深圳大学 | Orbital angular momentum mode sensing demodulation method and orbital angular momentum mode sensing system |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1596246A1 (en) * | 2004-05-13 | 2005-11-16 | Fujitsu Limited | Modulator for an optical transmitter, push-pull driven modulator, and an asymmetric modulator |
| CN101334315A (en) * | 2008-06-25 | 2008-12-31 | 北京理工大学 | Method and device for measuring light beam orbit angular momentum spectrum |
| CN102148067A (en) * | 2011-01-27 | 2011-08-10 | 西北工业大学 | Device for generating rotary combined vortex light beam |
| CN103792605A (en) * | 2013-12-11 | 2014-05-14 | 南京大学 | Forked liquid crystal grating preparation method and application of forked liquid crystal grating in vortex beam |
| CN204479017U (en) * | 2015-03-13 | 2015-07-15 | 浙江师范大学 | Spiral phase shift interference instrument apparatus |
| CN104833314A (en) * | 2015-06-03 | 2015-08-12 | 中国科学技术大学 | High-resolution optical fiber strain sensor and measuring method |
-
2017
- 2017-03-14 CN CN201710149972.0A patent/CN106802160B/en not_active Expired - Fee Related
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1596246A1 (en) * | 2004-05-13 | 2005-11-16 | Fujitsu Limited | Modulator for an optical transmitter, push-pull driven modulator, and an asymmetric modulator |
| CN101334315A (en) * | 2008-06-25 | 2008-12-31 | 北京理工大学 | Method and device for measuring light beam orbit angular momentum spectrum |
| CN102148067A (en) * | 2011-01-27 | 2011-08-10 | 西北工业大学 | Device for generating rotary combined vortex light beam |
| CN103792605A (en) * | 2013-12-11 | 2014-05-14 | 南京大学 | Forked liquid crystal grating preparation method and application of forked liquid crystal grating in vortex beam |
| CN204479017U (en) * | 2015-03-13 | 2015-07-15 | 浙江师范大学 | Spiral phase shift interference instrument apparatus |
| CN104833314A (en) * | 2015-06-03 | 2015-08-12 | 中国科学技术大学 | High-resolution optical fiber strain sensor and measuring method |
Non-Patent Citations (2)
| Title |
|---|
| 施建珍等: "用四台阶相位板产生涡旋光束", 《物理学报》 * |
| 郭苗军等: "基于螺旋相位板的涡旋光束的产生与干涉", 《激光与光电子学进展》 * |
Cited By (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107707300A (en) * | 2017-09-26 | 2018-02-16 | 南京邮电大学 | A kind of method of the non-aligned OAM multiplex systems crosstalk of suppression based on RVP modulation |
| CN107707300B (en) * | 2017-09-26 | 2020-07-07 | 南京邮电大学 | RVP modulation-based method for inhibiting crosstalk of non-aligned OAM multiplexing system |
| CN108645431A (en) * | 2018-05-30 | 2018-10-12 | 西安工业大学 | A kind of fitting Peak Search Method for the long correlation demodulation of optical fiber Fabry-Perot sensor chamber |
| CN108645431B (en) * | 2018-05-30 | 2020-08-07 | 西安工业大学 | Fitting peak searching method for cavity length correlation demodulation of optical fiber Fabry-Perot sensor |
| CN108827344A (en) * | 2018-07-20 | 2018-11-16 | 任元 | A kind of gyroscopic effect verifying device of wave-particle vortex gyro |
| CN108827344B (en) * | 2018-07-20 | 2022-06-03 | 任元 | Gyro effect verification device of wave particle vortex gyro |
| CN111238634A (en) * | 2020-02-17 | 2020-06-05 | 北京理工大学 | Light beam orbital angular momentum spectrum analysis method and device based on interference |
| CN111238634B (en) * | 2020-02-17 | 2020-12-15 | 北京理工大学 | Light beam orbital angular momentum spectrum analysis method and device based on interference |
| CN114140383A (en) * | 2021-10-25 | 2022-03-04 | 深圳大学 | Sensing demodulation method for orbital angular momentum mode |
| WO2023070855A1 (en) * | 2021-10-25 | 2023-05-04 | 深圳大学 | Orbital angular momentum mode sensing demodulation method and orbital angular momentum mode sensing system |
| CN114964328A (en) * | 2022-05-10 | 2022-08-30 | 南京师范大学 | All-fiber angular momentum interference sensing measurement system and method based on spiral grating |
| CN114964328B (en) * | 2022-05-10 | 2023-12-05 | 南京师范大学 | All-fiber angular momentum interferometry sensing measurement system and method based on spiral grating |
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