CN108204827A - A kind of phase-shifted fiber grating demodulating system - Google Patents
A kind of phase-shifted fiber grating demodulating system Download PDFInfo
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- G01D5/35306—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 an interferometer arrangement
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- 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
- G01D5/35383—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 multiple sensor devices using multiplexing techniques
- G01D5/35387—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 multiple sensor devices using multiplexing techniques using wavelength division multiplexing
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- 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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- 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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- G01D5/35396—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 multiple sensor devices using multiplexing techniques using other forms of multiplexing
Abstract
The invention discloses a kind of phase-shifted fiber grating demodulating systems, are sensed simultaneously to solve the problems, such as that existing phase-shifted fiber grating sensor-based system can not carry out multiple spot, realize that demodulation accuracy is high, can be multiplexed multiple phase-shifted fiber gratings, and measurement range is big.The system comprises frequency swept laser, coupler, first annular device, the second circulator, phase-shifted fiber grating array, gas absorption chamber, optical fiber FP interferometers, photodetector group, data acquisition device and demodulation modules.
Description
Technical field
The present invention relates to fibre optical sensor field, more particularly to a kind of phase-shifted fiber grating demodulating system.
Background technology
Fiber bragg grating is as a kind of new sensor, because the advantages of its uniqueness has more and more been closed
Note, application field are also increasingly extensive.Compared to traditional electricity, optical sensor, the transducing signal of fiber grating is compiled for wavelength
Code high sensitivity and is easy to be multiplexed without by electromagnetic interference.When it by ambient temperature, pressure when physical quantitys are influenced,
Its centre wavelength can change, therefore the sensor based on fiber grating can be used for measuring the variation of external physical quantity.Optical fiber
Grating sensing system has many advantages, such as corrosion-resistant, stable chemical performance, small, light-weight, can be widely applied to measure temperature,
The physical quantitys such as pressure, strain, acceleration have obtained extensively at present in fields such as civil structure, aerospace, petrochemical industry and medicine
General application.
Traditional fiber grating sensor reflection bandwidth is 0.2nm-0.5nm, and temperature and the demodulation accuracy highest strained can
Reach 0.1 DEG C and 1 microstrain.And demand of the sensory field to high-precision sensor is increasingly increasing, the demodulation of fiber grating
Precision is limited to its reflection bandwidth, reduces reflection bandwidth and is conducive to improve wavelength resolution.Phase-shifted fiber grating is as a kind of new
The fiber grating of type, narrowband transmission peaks are enabled it to for high-precision sensing field, such as ultrasonic sensing, weak signal possessed by it
Detection etc..Phase-shifted fiber grating is a kind of non-homogeneous periodic optical grating, and index distribution is discontinuous.The grating is in conventional fiber cloth
The a certain privileged site of glug grating introduces the phase shift of π, generates the grating of 2 mutual out-phase.The grating class of this 2 mutual out-phase
Wavelength selective resonance chamber is similar to, the light of resonance wavelength is allowed to be injected into stopband, the extremely narrow transmission of a line width is opened in stopband
Window, the 3-dB bandwidth of the window is about 10pm, and bandwidth reduces a number compared with the reflection bandwidth of ordinary optic fibre grating
Magnitude, and the centre wavelength of narrowband transmission peaks and external world's strain, temperature are in a linear relationship, therefore are suitable for high-precision sensing.
Phase-shifted fiber grating traditional demodulation scheme uses edge filter method more, although the demodulation scheme high sensitivity,
It is easily influenced by environment temperature, the centre wavelength of adjusting light source in real time is needed to realize optimum sensitivity, increases system complex
Degree.In addition the measurement range of the program is small, can only cover the size of transmission bandwidth, the range of about 10pm.It is limited to manufacture craft,
The centre wavelength of each phase-shifted fiber grating can not accomplish the consistency of pm magnitudes, so each sensing point is required to be equipped with one
Narrow-linewidth laser light source can not use a set of light-source system to carry out multiple spot and sense simultaneously.
Invention content
The defects of in order to overcome the prior art, the technical problem to be solved in the present invention is to provide a kind of phase-shifted fiber grating solutions
Adjusting system senses simultaneously to solve the problems, such as that existing phase-shifted fiber grating sensor-based system can not carry out multiple spot, realizes demodulation essence
Degree is high, can be multiplexed multiple phase-shifted fiber gratings, and measurement range is big.
In order to solve the above technical problems, a kind of phase-shifted fiber grating demodulating system in the present invention, including frequency swept laser,
Coupler, first annular device, the second circulator, phase-shifted fiber grating array, gas absorption chamber, optical fiber FP interferometers, photoelectricity are visited
Survey device group, data acquisition device and demodulation module；
The sweep light of the frequency swept laser output is divided into the first via, the second road and third road after the coupler and sweeps
Frequency light；After the first via sweep light is incident on the phase-shifted fiber grating array by the first annular device, and pass through institute
State first annular device output phase shift fiber grating sensing signal；After second tunnel sweep light is incident on the gas absorption chamber,
The transmission signal of output gas absorption chamber；Third road sweep light is incident on the optical fiber FP by second circulator to be done
After interferometer, and pass through the second circulator output optical fibre FP interferometer reflection signals；The phase-shifted fiber grating transducing signal,
The transmission signal of the gas absorption chamber and the optical fiber FP interferometer reflections signal are after the photodetector group, respectively
After being converted into corresponding analog signal, collection of simulant signal is completed by the data acquisition device；The demodulation module for pair
The analog signal of acquisition is demodulated.
Optionally, the instantaneous line width of the frequency swept laser is less than 10pm magnitudes.
Optionally, phase-shifted fiber grating array is connected in by least two phase-shifted fiber grating in same root optical fiber.
Specifically, phase-shifted fiber grating array is formed by being connected at least two phase-shifted fiber grating in same root optical fiber.
Specifically, the phase-shifted fiber grating array carries out port number extension by space division multiplexing.
Optionally, the photodetector group includes the first photodetector, the second photodetector and the spy of third photoelectricity
Survey device.
Optionally, third road sweep light is incident on the optical fiber FP interferometers by second circulator, passes through
After the optical fiber FP interferometers such as carry out at the wave numbers subdivision, and the wave numbers interval reflection peak such as there is by second circulator output
Optical fiber FP interferometer reflection signals.
Specifically, the demodulation module after the analog signal of acquisition is carried out digital-to-analogue conversion respectively, obtains gas
Body absorption spectra, optical fiber FP interferometer reflections spectrum and phase-shifted fiber grating transmission spectrum；
Using the gas absorption spectrum as absolute wavelength standard, according to the gas absorption spectrum and the optical fiber FP interferometers
The relative position relation of each reflection peak of reflectance spectrum determines the absolute wavelength of each reflection peak of optical fiber FP interferometer reflections spectrum；
The phase-shifted fiber grating transmission spectrum is demodulated based on the absolute wavelength.
Specifically, it is described that the phase-shifted fiber grating transmission spectrum is demodulated based on the absolute wavelength, including：
Determine the time-domain position of the narrowband transmission peaks of the phase-shifted fiber grating transmission spectrum；
According to the absolute wavelength, adjacent reflection peak is found in the time-domain position both sides；
According to the reflection peak found, the middle cardiac wave of phase-shifted fiber grating narrowband transmission peaks is calculated by linear interpolation algorithm
It is long, so as to fulfill the demodulation of phase-shifted fiber grating.
Specifically, the linear interpolation algorithm is specially：
In formula, λsensorFor the centre wavelength of phase-shifted fiber grating narrowband transmission peaks, tsensorTime domain for narrowband transmission peaks
Position, tref1And tref2The respectively position of the adjacent reflection peak of the time-domain position both sides, λref1And λref2Respectively both sides
The corresponding wavelength of adjacent reflection peak.
The present invention has the beneficial effect that：
The present invention effectively solves the problems, such as that existing phase-shifted fiber grating sensor-based system can not carry out multiple spot and sense simultaneously, realizes
Demodulation accuracy is high, can be multiplexed multiple phase-shifted fiber gratings, and measurement range is big.
Description of the drawings
Fig. 1 is a kind of structure diagram of phase-shifted fiber grating demodulating system in the embodiment of the present invention；
Fig. 2 is demodulating algorithm principle flow chart in the embodiment of the present invention；
Fig. 3 is time-domain signal schematic diagram on three detectors in the embodiment of the present invention.
Specific embodiment
In order to solve problem of the prior art, the present invention provides a kind of phase-shifted fiber gratings based on frequency sweep method to demodulate system
System.The non-linear jittering noise for the swept light source that phase-shifted fiber grating demodulating system proposed by the present invention uses and phase shift optical fiber light
The narrowband transmission peaks bandwidth of grid is in 10pm magnitudes, if using traditional gamma correction scheme, the error introduced is larger,
Therefore it needs to carry out high-precision gamma correction.Use the combined type based on optical fiber FP interferometers and gas absorption chamber exhausted thus
Wavelength reference is calibrated non-linear in length scanning, nonlinear calibration precision is improved to pm magnitudes, and by wavelength-division, when
Divide multiplexing that multiple phase shift optical fibers can be multiplexed on an optical fiber and carry out multiple spot high-precision large-range sensing.Below in conjunction with attached drawing with
And embodiment, the present invention will be described in further detail.It should be appreciated that specific embodiment described herein is only explaining
The present invention does not limit the present invention.
As shown in Figure 1, the embodiment of the present invention provides a kind of phase-shifted fiber grating demodulating system, including frequency swept laser 1,
1x3 couplers 2, first annular device 3, the second circulator 8, phase-shifted fiber grating array 4, gas absorption chamber 6, optical fiber FP interferometers
9th, photodetector group (including photoelectric sensor 5,7 and 10), data acquisition device 11 and demodulation module 12；
The sweep light that the frequency swept laser 1 exports is divided into the first via, the second road and third road after the coupler 2
Sweep light；After the first via sweep light is incident on the phase-shifted fiber grating array 4 by the first annular device 3, and lead to
Cross the 3 output phase shift fiber grating sensing signal of first annular device；Second tunnel sweep light is incident on the gas and absorbs
Behind room 6, the transmission signal of output gas absorption chamber；Third road sweep light is incident on described by second circulator 8
After optical fiber FP interferometers 9, and pass through the 8 output optical fibre FP interferometer reflection signals of the second circulator；The phase shift optical fiber light
Grid transducing signal, the transmission signal of the gas absorption chamber and the optical fiber FP interferometer reflections signal pass through the photodetection
After device group, after being converted into corresponding analog signal respectively, collection of simulant signal is completed by the data acquisition device 11；The solution
Mode transfer block 12 is used to be demodulated the analog signal of acquisition.
On the basis of above-described embodiment, it is further proposed that the variant embodiment of above-described embodiment, needs what is illustrated herein
It is, in order to make description brief, the only description and the difference of above-described embodiment in each variant embodiment.
In one embodiment of the invention, the instantaneous line width of the frequency swept laser is less than 10pm magnitudes.Phase shift optical fiber
Grating array is connected in by least two phase-shifted fiber grating in same root optical fiber.
Furtherly, at least two phase-shifted fiber grating is connected in by wavelength-division and time-sharing multiplex in same root optical fiber.
It further says, the phase-shifted fiber grating array carries out port number extension by space division multiplexing.
The photodetector group includes the first photodetector 5, the second photodetector 7 and third photodetector
10。
Wherein, demodulation module 12 is specially processor.
Present invention uses narrow linewidth frequency swept laser 1, the instantaneous line width of the laser is less than 10pm magnitudes, can be in time domain
On collect in phase-shifted fiber grating reflectance spectrum narrowband transmission peak-to-peak signal.
Meanwhile gas absorption chamber 6 and optical fiber FP interferometers 9 have been used collectively as wavelength reference.Gas absorption chamber conduct
Absolute wavelength standard, and optical fiber FP interferometers 9 then as etc. wave numbers interval multiple wavelengths filter, the two may be constructed with absolute
The wavelength ruler of lambad labeling.Furtherly, optical fiber FP interferometers 9 such as can carry out frequency sweep spectrum at wave numbers subdivision, the interferometer reflection
Frequency sweep track in spectrum between each peak can be approximately linear scan, non-linear during frequency sweep so as to effectively calibrate, and improve wave
The accuracy of long demodulation.
In another embodiment of the present invention, third road sweep light is incident on described by second circulator
Optical fiber FP interferometers after the optical fiber FP interferometers such as carry out at the wave numbers subdivision, and pass through the second circulator output tool
The optical fiber FP interferometer reflection signals of wave numbers interval reflection peak such as have.
Furtherly, the demodulation module after the analog signal of acquisition is carried out digital-to-analogue conversion respectively, obtains
Gas absorption spectrum, optical fiber FP interferometer reflections spectrum and phase-shifted fiber grating transmission spectrum；
Using the gas absorption spectrum as absolute wavelength standard, according to the gas absorption spectrum and the optical fiber FP interferometers
The relative position relation of each reflection peak of reflectance spectrum determines the absolute wavelength of each reflection peak of optical fiber FP interferometer reflections spectrum；
The phase-shifted fiber grating transmission spectrum is demodulated based on the absolute wavelength.
Wherein, it is described that the phase-shifted fiber grating transmission spectrum is demodulated based on the absolute wavelength, including：
Determine the time-domain position of the narrowband transmission peaks of the phase-shifted fiber grating transmission spectrum；
According to the absolute wavelength, adjacent reflection peak is found in the time-domain position both sides；
According to the reflection peak found, the middle cardiac wave of phase-shifted fiber grating narrowband transmission peaks is calculated by linear interpolation algorithm
It is long, so as to fulfill the demodulation of phase-shifted fiber grating.
Wherein, the linear interpolation algorithm is specially：
In formula, λsensorFor the centre wavelength of phase-shifted fiber grating narrowband transmission peaks, tsensorTime domain for narrowband transmission peaks
Position, tref1And tref2The respectively position of the adjacent reflection peak of the time-domain position both sides, λref1And λref2Respectively both sides
The corresponding wavelength of adjacent reflection peak.
The embodiment of the present invention composes the relative position relation at each peak according to gas absorption spectrum line and optical fiber FP interferometer reflections, really
Determine the absolute wavelength that optical fiber FP interferometer reflections compose each peak.Then the narrowband that phase-shifted fiber grating is found by peak-seeking algorithm transmits
The time-domain position at peak, in this position, the reflection peak of adjacent optical fiber FP interferometers is found in both sides, and then passes through linear interpolation algorithm
The centre wavelength of phase-shifted fiber grating narrowband transmission peaks is calculated, large scale and high accuracy while realizing multiple phase-shifted fiber gratings
Demodulation.
Illustrate the present invention embodiment.
As shown in Figure 1, narrow linewidth frequency swept laser 1 is a light source with output tail optical fiber, output light is through overcoupling
Device 2 is divided into three beams, and the first beam reaches phase-shifted fiber grating array 4 by circulator 3 and (is illustrated as 2 phase-shifted fiber grating strings
Connection), reflected light is received by the third port of circulator by photodetector 5；Second beam light of coupler output passes through
Gas absorption chamber 6, transmitted light are received by photodetector 7；The three-beam of coupler passes through circulator 8, reaches optical fiber FP
Interferometer 9, third port of the interference signal through circulator are received by photodetector 10.Due to narrow linewidth frequency swept laser
The periodically continued variation at any time of its output center wavelength, therefore reflection or transmitted spectrum signal can be converted into time domain light intensity letter
Number, it is received by three photodetectors, enters the solution based on data collecting card 11 and processor 12 after being converted into analog electrical signal
Mode transfer block.
In reference signal, the absorption line of gas absorption chamber can be used as absolute wavelength standard, optical fiber FP interferometers because
The special designing of its chamber length can obtain the interference fringe that FSR is 50pm magnitudes, can be with shape with reference to the absorption line of gas absorption chamber
Into lambad labeling etc. wave numbers interval wavelength ruler, the centre wavelength of the narrowband transmission peaks of phase-shifted fiber grating can be carried out high
Precision measure.The method of measurement is linear interpolation method, can measure phase shift light by measuring the relative position of narrowband transmission peaks
The variation of fine raster center wavelength, realizes the sensing and demodulating to external physical quantity.
The flow chart of the demodulating algorithm of the present invention using data collecting card as shown in Fig. 2, acquire three photoelectricity after synchronizing
Analog signal on detector using the acquisition signal of a complete cycle as process object, first carries out analog electrical signal
Digital-to-analogue conversion and digital filtering, by the way that suitable peak-seeking threshold value and peak width is set to determine the position of phase-shifted fiber grating narrowband transmission peaks
It puts.As shown in figure 3,1. signal is phase-shifted fiber grating transducing signal, 2. signal is optical fiber FP interferometer reflection peak-to-peak signals, signal
3. the transmission signal for gas absorption chamber.By the transmission peaks of gas absorption chamber, its line width is relatively narrow, about 10pm magnitudes, and optical fiber
The FSR of FP interferometers is about 50pm, and it is then a definite value to be converted into frequency values, therefore can pass through the absolute wave of gas absorption spectrum line
Long and interferometer FSR value can orient the absolute wavelength at each interferometer reflection peak, thus above-mentioned two reference signal just structure
Into the wavelength ruler at the wave numbers interval such as one.
By taking wherein some sensing phase-shifted fiber grating as an example, if meta position is set to t at that timesensor, can be found by peak-seeking algorithm
The position t at the interferometer reflection peak of its adjacent both sides in time domainref1And tref2, corresponding wavelength is respectively λref1And λref2.It is logical
Sensing phase-shifted fiber grating centre wavelength can be solved by crossing interpolation algorithmAnd in this
The variation of cardiac wave length and external physical quantity can realize the sensing to external physical quantity in one-to-one relationship.
The beneficial effects of the invention are as follows：
1. the multiplexing of multiple phase-shift fiber grating.Multiple phase-shifted fiber gratings can be connected on same by wavelength-division, time division multiplexing
In root optical fiber, and can port number extension further be carried out by space division multiplexing, improve the sensing point quantity of system.
2. it is big to demodulate range.I.e. dynamic range is big, and the range of conventional method demodulation is saturating no more than phase-shifted fiber grating narrowband
The 3-dB bandwidth at peak, about 10pm are penetrated, and the demodulation rule is not limited, can carry out wide range sensing, demodulation range is
It is determined by swept bandwidth and grating multiplexing quantity.
3. high-precision.Used gamma correction method, using can to optical fiber FP interferometers that swept frequency range is finely divided (from
It is 50pm magnitudes by spectrum journey), make frequency sweep is non-linear to be calibrated, and high-precision absolute wavelength is obtained by gas absorption chamber
Demodulation.
Although This application describes the particular example of the present invention, those skilled in the art can not depart from the present invention generally
Variant of the invention is designed on the basis of thought.
Under the inspiration that those skilled in the art conceive in the technology of the present invention, on the basis of the content of present invention is not departed from, also
Various improvement can be made to the present invention, this still falls within the scope and spirit of the invention.
Claims (10)
1. a kind of phase-shifted fiber grating demodulating system, which is characterized in that the system comprises frequency swept laser, coupler, first
Circulator, the second circulator, phase-shifted fiber grating array, gas absorption chamber, optical fiber FP interferometers, photodetector group, data
Harvester and demodulation module；
The sweep light of the frequency swept laser output is divided into the first via, the second road and third road frequency sweep after the coupler
Light；After the first via sweep light is incident on the phase-shifted fiber grating array by the first annular device, and pass through described
First annular device output phase shift fiber grating sensing signal；It is defeated after second tunnel sweep light is incident on the gas absorption chamber
Go out the transmission signal of gas absorption chamber；Third road sweep light is incident on the optical fiber FP by second circulator interferes
After instrument, and pass through the second circulator output optical fibre FP interferometer reflection signals；The phase-shifted fiber grating transducing signal, institute
State gas absorption chamber transmission signal and the optical fiber FP interferometer reflections signal after the photodetector group, turn respectively
After changing corresponding analog signal into, collection of simulant signal is completed by the data acquisition device；The demodulation module is used for adopting
The analog signal of collection is demodulated.
2. the system as claimed in claim 1, which is characterized in that the instantaneous line width of the frequency swept laser is less than 10pm magnitudes.
3. the system as claimed in claim 1, which is characterized in that phase-shifted fiber grating array is by being connected in same root optical fiber extremely
Few 2 phase-shifted fiber gratings composition.
4. system as claimed in claim 3, which is characterized in that at least two phase-shifted fiber grating passes through wavelength-division and timesharing
Multiplexing is connected in same root optical fiber.
5. system as claimed in claim 4, which is characterized in that the phase-shifted fiber grating array is led to by space division multiplexing
Road number extension.
6. the system as claimed in claim 1, which is characterized in that the photodetector group includes the first photodetector, the
Two photodetectors and third photodetector.
7. the system as described in any one in claim 1-5, which is characterized in that third road sweep light passes through described
Second ring device is incident on the optical fiber FP interferometers, after the optical fiber FP interferometers such as carry out at the wave numbers subdivision, and passes through institute
State the second circulator output with etc. wave numbers interval reflection peak optical fiber FP interferometer reflection signals.
8. system as claimed in claim 7, which is characterized in that the demodulation module, specifically for by the analog signal acquired
After carrying out digital-to-analogue conversion respectively, gas absorption spectrum, optical fiber FP interferometer reflections spectrum and phase-shifted fiber grating transmission spectrum are obtained；
Using the gas absorption spectrum as absolute wavelength standard, according to the gas absorption spectrum and the optical fiber FP interferometer reflections
The relative position relation of each reflection peak of spectrum determines the absolute wavelength of each reflection peak of optical fiber FP interferometer reflections spectrum；
The phase-shifted fiber grating transmission spectrum is demodulated based on the absolute wavelength.
9. system as claimed in claim 8, which is characterized in that described to be based on the absolute wavelength to the phase-shifted fiber grating
Transmission spectrum is demodulated, including：
Determine the time-domain position of the narrowband transmission peaks of the phase-shifted fiber grating transmission spectrum；
According to the absolute wavelength, adjacent reflection peak is found in the time-domain position both sides；
According to the reflection peak found, the centre wavelength of phase-shifted fiber grating narrowband transmission peaks is calculated by linear interpolation algorithm,
So as to fulfill the demodulation of phase-shifted fiber grating.
10. system as claimed in claim 9, which is characterized in that the linear interpolation algorithm is specially：
In formula, λsensorFor the centre wavelength of phase-shifted fiber grating narrowband transmission peaks, tsensorFor the time-domain position of narrowband transmission peaks,
tref1And tref2The respectively position of the adjacent reflection peak of the time-domain position both sides, λref1And λref2Respectively both sides is adjacent
Reflection peak corresponding wavelength.
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| CN113670351A (en) * | 2020-05-15 | 2021-11-19 | 大连理工大学 | VCSEL multiplexing-based fiber bragg grating array measuring method, device and system |
| WO2024077503A1 (en) * | 2022-10-09 | 2024-04-18 | 广东感芯激光科技有限公司 | Interferometer absolute-displacement demodulation system and method using gas absorption spectrum as reference |
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