CN106019467B - A kind of production method of fiber grating resistant to high temperature - Google Patents
A kind of production method of fiber grating resistant to high temperature Download PDFInfo
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- CN106019467B CN106019467B CN201610541271.7A CN201610541271A CN106019467B CN 106019467 B CN106019467 B CN 106019467B CN 201610541271 A CN201610541271 A CN 201610541271A CN 106019467 B CN106019467 B CN 106019467B
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- fiber grating
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- 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
- G02B6/02123—Refractive index modulation gratings, e.g. Bragg gratings characterised by the method of manufacture of the grating
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- General Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Optical Fibers, Optical Fiber Cores, And Optical Fiber Bundles (AREA)
Abstract
The present invention provides a kind of production method of fiber grating resistant to high temperature, step 1: the normal single mode quartz optical fiber of polyimide coating is carried out to carry hydrogen processing in hyperbaric environment；Step 2: it places the fiber in high temperature roaster and anneals；Step 3: optical fiber grating region to be written is impregnated at high temperature using the concentrated sulfuric acid；Step 4: fiber grating inscription is carried out using ultraviolet laser；Grating bandwidth growth rate is detected between 2pm/s ~ 4pm/s, after stopping growing to grating spectral bandwidth, continues exposure a period of time；Step 5: naked fibre position is coated with using polyimides；Step 6: fiber grating is put into 400 ± 10 DEG C of oven for baking and carries out high-temperature heat treatment and on-line checking grating core wavelength and reflectivity.The sensor of high-temperature resistant optical fiber preparing grating of the invention can be directly used in 400 DEG C of working environments, can be simpler direct using the sensor of this Grating Design, and data are also more accurate.
Description
Technical field
The present invention relates to the production method of fiber grating more particularly to the production methods of fiber grating resistant to high temperature.
Background technique
Currently as some high-temperature fields such as petroleum industry, heat power station, aerospace science and technology, metallurgical industry are sensed
Measurement requires energy fiber grating production sensor resistant to high temperature, therefore improving the stability of fiber grating at high temperature is to pass
Important.
Ordinary optic fibre grating can only steady operation in 200 DEG C or less environment, such as want with such preparing grating be applied to height
Sensor under warm environment needs to design by complicated encapsulation, or manufactures temperature gradient or convert stress for temperature change
Variation is further conducted to fiber grating, completes the measurement under hot environment with this.Such design can all cause biggish
Measurement error.
Current optical fiber grating can be divided into following four kinds by its temperature:
Type I type: i.e. ordinary optic fibre grating: under the irradiation of ultraviolet light, fiber core refractive index generating period sexually revises
And formed phase grid, but the periodic modulation of this refractive index be not it is permanent, as the temperature rises, grating it is anti-
The rate of penetrating can be reduced gradually, and such fiber grating can only be in 200 DEG C or less steady operations, when temperature is at 200 DEG C or more, grating
Reflectivity can decline as the temperature rises；When temperature is at 350 DEG C, after keeping the temperature several hours, grating has been wiped free of.
Type II type: the preparation of such fiber grating needs the ultraviolet laser of ultrahigh speed laser or higher energy density,
The energy density of high energy ultraviolet pulse is greater than 1000mJ/cm2/Pulse.Since there is high energy during grating is written
The nonlinear effect of ultraviolet laser makes fiber core that physical damage have occurred so as to cause the melting of quartz substrate, generates
Biggish refractive index periodic modulation.The fiber grating of this type stability with higher at high temperature, can 800 DEG C with
Lower stable work.
Type II A type: the type grating it is related with the dense effect of matrix material of optic fibre at grid mechanism, in Type
During grating is written in II A type fiber grating, under the irradiation of ultraviolet light, when refractive index positively-modulated depth elder generation is with exposure
Between increase and increase, Type I type fiber grating is formd, with the increase of ultraviolet light time, Type I type grating quilt
It partially or completely wipes, finally, producing refractive index negatively-modulated depth when accumulation energy density is greater than 500J/CM2, occurs
New reflection wavelength is formed Type II A type grating, and the type grating is with good stability at high temperature, can
Bear 500 DEG C to 700 DEG C of high temperature.
Regeneration grating: when being specifically heat-treated to load hydrogen ordinary optic fibre grating, it may occur that following reversible reaction is shown in
Following formula:
2 (Si-OH) ← → Si-O-Si+H2O (formula 1)
2 (Ge-OH) ← → Ge-O-Ge+H2O (formula 2)
As the temperature rises, the covalent bond of silicone hydroxyl (Si-OH) and germanium hydroxyl (Ge-OH) can die down, and reaction is continuous
It is carried out towards formula positive reaction, and regenerates silicon oxygen covalent bond (Si-O-Si) and germanium oxygen covalent bond (Ge-O-Ge) and hydrone
(H2O), related silicone hydroxyl (Si-OH) and germanium hydroxyl (Ge-OH) concentration with refractive index periodic modulation is caused constantly to reduce, because
This original reflectivity for carrying hydrogen fiber grating is smaller and smaller as the temperature rises, and when temperature is 790 DEG C, reflection spectral line disappears
It loses, with the further raising of temperature, carries the dense of the hydrone around the modulation of hydrogen fiber grating refractive index periodic original
Degree can increase, so as to cause the generation of the back reaction of above formula, at high temperature once more generate refractive index periodic tune
Related silicone hydroxyl (Si-OH) and germanium hydroxyl (Ge-OH) are made, therefore forms new refractive index periodic in the fibre core of optical fiber
Modulation, that is, generate new fiber grating --- regeneration grating.Regeneration grating is resistant to 800 celsius temperatures.
Current four kinds of fiber gratings have following defects that
TypeI type: under the conditions of being applicable only to environment temperature lower than 200 DEG C；
TypeII type: the reflectance spectrum bandwidth of grating is bigger than normal, and the loss of its transmission spectrum shortwave is big, and then influences the measurement of grating
Precision and wavelength-division multiplex ability, laser needed for preparing is expensive, and millions of costs of manufacture are higher easily.
TypeII A type: fiber grating fabrication cycle is long, and cost of manufacture is higher；
Regenerate grating: mechanical strength is poor, and qualification rate is low, and cost of manufacture is higher；
The sensor of high-temperature resistant optical fiber preparing grating of the invention can be directly used for using this light in 400 DEG C of working environments
The sensor of grid design can be simpler direct, and data are also more accurate.
The present invention has filled up the blank of the high-temperature resistant optical fiber grating of 200 to 400 DEG C of temperature sections.
The lower cost of manufacture of the present invention, is widely used in the various engineer applications of the temperature environment.
Summary of the invention
In order to solve the problems, such as that in the prior art, the present invention provides a kind of production method of fiber grating resistant to high temperature, packets
Include following steps:
Step 1: the general single mode fiber of polyimide coating is carried out to carry hydrogen processing in hyperbaric environment, has optical fiber
There is light sensitive characteristic；
Step 2: it places the fiber in high temperature roaster and anneals；
Step 3: optical fiber grating region to be written is impregnated under 120 ± 10 DEG C of environment using the concentrated sulfuric acid, to remove polyimides
Coat；
Step 4: carrying out fiber grating inscription using ultraviolet laser, inscribe optical pulse energy be set as 4.7 ±
0.2mJ/Pulse, set of frequency are 35 ± 10HZ；Grating bandwidth growth rate is detected between 2pm/s~4pm/s, to grating
After spectral bandwidth stops growing, continues exposure to stablize and effect is written；
Step 5: fiber grating is put into 400 ± 10 DEG C of oven for baking and carries out high-temperature heat treatment and on-line checking grating
Core wavelength and reflectivity, when grating spectral line is without occurring any deterioration phenomenon, high-temperature resistant optical fiber preparing grating is completed.
As a further improvement of the present invention, hyperbaric environment described in step 1 is in the environment of 1MPa to 20MPa.
As a further improvement of the present invention, after step 4 before step 5: using polyimides glue to naked fibre position
It sets and is coated with.
As a further improvement of the present invention, the step 2: placing the fiber in high temperature roaster and anneal, the height
Temperature is 100 DEG C to 180 DEG C.
As a further improvement of the present invention, the step 3: optical fiber is impregnated under 120 ± 5 DEG C of environment using the concentrated sulfuric acid
Grating region to be written, to remove polyimide coating layer.
As a further improvement of the present invention, the step 4: fiber grating quarter is carried out using 248nm ultraviolet laser
It writes.
As a further improvement of the present invention, it the step 4: inscribes optical pulse energy and is set as 4.7 ± 0.1mJ/
Pulse。
As a further improvement of the present invention, the step 4: set of frequency is 35 ± 5HZ.
As a further improvement of the present invention, the step 5: fiber grating is put into 400 DEG C of oven for baking and carries out height
Warm processing and on-line checking grating core wavelength and reflectivity.
As a further improvement of the present invention, the step 4: fiber grating is carried out using 248 ± 10nm ultraviolet laser
It inscribes.
Fiber grating of the present invention is to carry out process modification on the basis of ordinary optic fibre preparing grating, optical fiber carry hydrogen link into
The control of row pressure, and shorten and carry the hydrogen time.Increase high annealing link after carrying hydrogen, to the output ultraviolet light arteries and veins of ultraviolet laser
It rushes energy and frequency carries out special setting, and continue to be exposed processing after fiber grating growth.Above series of changes
It is kind all to be obtained by many experiments, achieve the effect that be resistant to 400 DEG C of high temperature with this, manufacturing process is simple, does not increase extra cost
Investment.
The index for the fiber grating that the present invention makes are as follows: bandwidth :≤0.2nm@3dB；Reflectivity: >=20%；
It can be directly invested in 400 DEG C of hot environments using the sensor of this preparing grating, easy to use, data are surveyed
Amount is accurate.
Optical fiber carries the principle that hydrogen improves UV Photosensitivity in Optical Fiber: being that will be put into certain pressure mixed with germanium ion general single mode fiber
In hydrogen environment, a period of time is stood.At this point, hydrogen will diffuse into the fibre core of optical fiber in the form of molecular state, when load hydrogen
When optical fiber is under the ultraviolet light irradiation of specific wavelength, Ge-O key and Si-O key in hydrogen molecule and fiber optic materials are had occurred instead
It answers, generates the GODC and Ge-OH with specific absorption band, Si-OH chemical bond, to improve the refractive index change for carrying hydrogen optical fiber
Change.The modulation amplitude for carrying the refractive index periodic of hydrogen optical fiber can reach 5.9x10-3.Compare do not carry hydrogen optical fibre refractivity variation mention
High two orders of magnitude, effectively improve the light sensitivity of optical fiber.
The principle of fiber grating annealing: due to being the load hydrogen grating of write-in under the irradiation of the ultraviolet laser of a pulse
Refractive index modulation depth it is very low, and its maximum reflection power is not also high, so that is generated is modulated with refractive index periodic
The silicone hydroxyl (Si-OH) of pass and the covalent bond of germanium hydroxyl (Ge-OH) are simultaneously insecure, at high temperature, silicone hydroxyl (Si-OH) and germanium hydroxyl
The covalent bond of base (Ge-OH) can die down, and regenerate silicon oxygen covalent bond (Si-O-Si) and germanium oxygen covalent bond (Ge-O-Ge) therefore
Modulating related silicone hydroxyl (Si-OH) and germanium hydroxyl (Ge-OH) concentration with refractive index periodic reduces, and causes to carry hydrogen weak fiber light
The reflection power of grid declines, for carrying hydrogen weak optical fiber Bragg grating in high-temperature annealing process, with the increase of annealing time, formula 1
Reversible reaction with formula 2 respectively reaches balance, and the concentration of silicone hydroxyl (Si-OH) and germanium hydroxyl (Ge-OH) is held essentially constant.
2 (Si-OH) ← → Si-O-Si+H2O (formula 1)
2 (Ge-OH) ← → Ge-O-Ge+H2O (formula 2)
Content of the inducible factor hydrogen in optical fiber number directly result in fiber grating write-in efficiency and as a result, hydrogen
Higher, grating writing fast speed, the attenuation after fiber grating annealing also can be larger；Hydrogen content is lower, grating writing
Efficiency reduces, and after hydrogen exhausts, will be unable to be written；Equally, the output pulse energy and frequency of laser and fiber grating
It is written with close relationship, energy is bigger, and frequency is higher, and the write efficiency of fiber grating is higher, but energy is excessive to damage
Optical fiber itself even interrupts optical fiber, leads to the reduction of its mechanical performance.Energy is smaller, and frequency is lower, the write-in effect of fiber grating
Rate is lower, or even can not be written, and the cooperation of the content of inducible factor hydrogen and the pulse energy of laser and frequency is to write out conjunction
The vital factor of lattice grating.
The beneficial effects of the present invention are:
The reliability test of high-temperature resistant optical fiber grating of the present invention is as follows:
High-temperature resistant optical fiber grating is placed in the stability for carrying out detection grating spectral line in 400 DEG C of muffle furnaces online, test
System schematic such as Fig. 1.
High-temperature resistant optical fiber grating test data analysis chart of the present invention such as Fig. 2.
Production process of the present invention is simple, requires process equipment low；It can directly be invested in 400 DEG C of working environments, effectively
The design difficulty of sensor is reduced, measurement accuracy is more accurate.It is low in cost, it is widely portable to the various engineerings of this temperature section
Using.
Detailed description of the invention
Fig. 1 is that of the invention high-temperature resistant optical fiber grating is placed in 400 DEG C of muffle furnaces carries out detection grating spectral line online
Stability, test macro schematic diagram；
Fig. 2 is the high-temperature resistant optical fiber grating that makes of the present invention in 400 degree of at a temperature of wavelength long-time stability and reflectivity
The tendency chart of long-time stability.
Specific embodiment
The present invention will be further described with reference to the accompanying drawing.
A kind of production method of fiber grating resistant to high temperature:
Step 1: it is small that the general single mode fiber that Polyimide (polyimides) coats is stored 24 in 10Mpa hydrogen
When, make optical fiber that there is light sensitive characteristic；
Step 2: placing the fiber in 150 DEG C of ovens and store 30 minutes, so that the inducible factor hydrogen in optical fiber reaches certain
Certain proportion state；
Step 3: using the concentrated sulfuric acid in 120 degree of bubble optical fiber grating regions to be written of high temperature, to remove polyimide coating layer；
Step 4: carrying out fiber grating inscription using 248nm ultraviolet laser, inscribes optical pulse energy and is set as 4.7
± 0.1mJ/Pulse, set of frequency are 35 ± 5HZ.Grating bandwidth growth rate is detected between 2pm/s~4pm/s, to grating
After spectral bandwidth stops growing, continue to stablize write-in effect in exposure 10 seconds；
Step 5: naked fibre position is coated with using polyimides glue.According to actual needs, it can not also do again
Coating.
Step 6: fiber grating is put into 400 DEG C of oven for baking and carries out high-temperature heat treatment and on-line checking grating spectral line
Central wavelength and reflectivity, when grating spectral line is without occurring any deterioration phenomenon, high-temperature resistant optical fiber preparing grating is completed.
The present invention obtains following result by largely test:
Grating of the present invention needs first to place the fiber in 150 DEG C of pot annealing 70-80 minutes roasting, reduction inducible factor hydrogen before inscribing
The levels of gas, and then the refractive index periodic modulation amplitude for carrying hydrogen optical fiber is reduced, the photosensitive property of the optical fiber made reaches one
A reasonable range；
The present invention when fiber grating is inscribed need to power to laser and frequency carry out specific setting, pass through experiment monochromatic light
Pulse energy is set as 4.7 ± 0.1mJ/Pulse, and optical pulse frequency is set as 35 ± 5HZ, and the grating spectral line write out at this time is stablized
Property is best.The unreasonable fiber grating that will will lead to of optical pulse energy parameter setting can not be normally written or destroy this body structure of optical fiber
The bad result for causing its mechanical strength to be deteriorated.
Bandwidth growth rate when the present invention inscribes grating under the above specified conditions is about 3pm/s.And it is composed in grating
Tape is wide stop growing after need to continue 10 ± 5s of exposure and may make that fiber grating is more stable.
Fig. 2 is the high-temperature resistant optical fiber grating that makes of the present invention in 400 degree of at a temperature of wavelength long-time stability and reflectivity
The tendency chart of long-time stability, as can be seen from the figure the high-temperature stability of the two is fine, adapts to the needs of Practical Project completely.
The above content is a further detailed description of the present invention in conjunction with specific preferred embodiments, and it cannot be said that
Specific implementation of the invention is only limited to these instructions.For those of ordinary skill in the art to which the present invention belongs, exist
Under the premise of not departing from present inventive concept, a number of simple deductions or replacements can also be made, all shall be regarded as belonging to of the invention
Protection scope.
Claims (8)
1. a kind of production method of fiber grating resistant to high temperature, which comprises the steps of:
Step 1: the general single mode fiber of polyimide coating is carried out to carry hydrogen processing in hyperbaric environment, makes optical fiber that there is light
Quick characteristic；The hyperbaric environment is in the environment of 1MPa to 20MPa；
Step 2: it places the fiber in high temperature roaster and anneals；The high temperature is 100 DEG C to 180 DEG C；
Step 3: optical fiber grating region to be written is impregnated under 120 ± 10 DEG C of environment using the concentrated sulfuric acid, to remove polyimide coating
Layer；
Step 4: carrying out fiber grating inscription using ultraviolet laser, inscribes optical pulse energy and is set as 4.7 ± 0.2mJ/
Pulse, set of frequency are 35 ± 10HZ；Grating bandwidth growth rate is detected between 2pm/s ~ 4pm/s, to grating spectral bandwidth
After stopping growing, continues exposure to stablize and effect is written；
Step 5: fiber grating is put into 400 ± 10 DEG C of oven for baking and carries out high-temperature heat treatment and on-line checking grating spectral line
Central wavelength and reflectivity, when grating spectral line is without occurring any deterioration phenomenon, high-temperature resistant optical fiber preparing grating is completed.
2. a kind of production method of fiber grating resistant to high temperature according to claim 1, it is characterised in that: after step 4
Before step 5: being coated with using polyimides glue to naked fibre position.
3. a kind of production method of fiber grating resistant to high temperature according to claim 1, it is characterised in that: the step
Three: optical fiber grating region to be written is impregnated under 120 ± 5 DEG C of environment using the concentrated sulfuric acid, to remove polyimide coating layer.
4. a kind of production method of fiber grating resistant to high temperature according to claim 1, it is characterised in that: the step
Four: carrying out fiber grating inscription using 248nm ultraviolet laser.
5. a kind of production method of fiber grating resistant to high temperature according to claim 1, it is characterised in that: the step
Four: inscribing optical pulse energy and be set as 4.7 ± 0.1mJ/Pulse.
6. a kind of production method of fiber grating resistant to high temperature according to claim 1, it is characterised in that: the step
Four: set of frequency is 35 ± 5HZ.
7. a kind of production method of fiber grating resistant to high temperature according to claim 1, it is characterised in that: the step
Five: fiber grating being put into 400 DEG C of oven for baking and carries out high-temperature heat treatments and on-line checking grating core wavelength and anti-
Penetrate rate.
8. a kind of production method of fiber grating resistant to high temperature according to claim 1, it is characterised in that: the step
Four: carrying out fiber grating inscription using 248 ± 10nm ultraviolet laser.
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| CN108240859B (en) * | 2016-12-26 | 2020-12-01 | 深圳太辰光通信股份有限公司 | Parameter design method of fiber grating vibration sensor |
| CN107478354A (en) * | 2017-10-09 | 2017-12-15 | 中国计量大学 | A kind of pyrostat based on the miniature temperature probe of high germnium doped fiber |
| CN109445018B (en) * | 2018-10-24 | 2020-01-31 | 武汉理工大学 | Preparation method and system of regenerated weak grating array |
| CN113359226A (en) * | 2021-06-02 | 2021-09-07 | 上海飞博激光科技有限公司 | Local heat treatment method for high-power laser fiber grating |
| CN113759459B (en) * | 2021-09-13 | 2024-04-12 | 北京知觉科技有限公司 | Preparation method of high-temperature-resistant fiber Bragg grating array |
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| CN102169028A (en) * | 2011-01-20 | 2011-08-31 | 中国电力科学研究院 | System for measuring temperature in thyristor in real time |
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| JP4413972B2 (en) * | 2008-02-01 | 2010-02-10 | 古河電気工業株式会社 | Manufacturing method of fiber grating |
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| CN102169028A (en) * | 2011-01-20 | 2011-08-31 | 中国电力科学研究院 | System for measuring temperature in thyristor in real time |
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| 基于相位掩模技术的光纤布拉格光栅制作工艺研究;王广祥 等;《河北科技大学学报》;20111215;第32卷(第6期);563-566 |
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