CN1278069A - Optical fiber grating mfg. method with chirp and apodization function adjustment - Google Patents
Optical fiber grating mfg. method with chirp and apodization function adjustment Download PDFInfo
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- CN1278069A CN1278069A CN 00109436 CN00109436A CN1278069A CN 1278069 A CN1278069 A CN 1278069A CN 00109436 CN00109436 CN 00109436 CN 00109436 A CN00109436 A CN 00109436A CN 1278069 A CN1278069 A CN 1278069A
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- 239000013307 optical fiber Substances 0.000 title claims abstract description 42
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- XKRFYHLGVUSROY-UHFFFAOYSA-N argon Substances [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 claims description 3
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- 238000004891 communication Methods 0.000 abstract description 3
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- 238000000985 reflectance spectrum Methods 0.000 description 11
- 238000004519 manufacturing process Methods 0.000 description 8
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- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 3
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- 230000008878 coupling Effects 0.000 description 3
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- 238000010586 diagram Methods 0.000 description 3
- 238000005516 engineering process Methods 0.000 description 3
- 239000001257 hydrogen Substances 0.000 description 3
- 229910052739 hydrogen Inorganic materials 0.000 description 3
- 230000003287 optical effect Effects 0.000 description 3
- 238000001228 spectrum Methods 0.000 description 3
- 241001270131 Agaricus moelleri Species 0.000 description 2
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- 238000011161 development Methods 0.000 description 1
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- 238000009966 trimming Methods 0.000 description 1
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Abstract
The present invention relates to the photo electron and optical fiber communication field including use of ultraviolet rag laser as light source, the scanning reflective mirror fixed on scanning moving platform; the photo sensitive optical fiber fixed at proper position; uniform plase template set before optical fiber; by online input to set apodization function parameter, use of software in microcomputer to control moving state of scanning moving platform, to carry the scanning reflective mirror run according to said apodization function curve symmetrical distribution rule, scanning the optical fiber, the exposure of different optical fiber points distributing according to said function curve, so that the optical fiber grating is obtained. The present invention is simple, economy and fractical, and possesses good reproducibility and flexibility.
Description
The invention belongs to photoelectron technology and technical field of optical fiber communication.Be particularly related to the fiber grating manufacturing technology.
Since fiber grating comes out, experienced the course of two more than ten years.The manufacturing technology of fiber grating has also experienced several times and has changed.People such as K.Hill at first invented wrting method in the fiber grating in 1978, write light inlet and were introduced by the end face of optical fiber, form standing wave and realize that grating writes in optical fiber.1989, people such as G.Meltz invented the outer wrting method of optical fiber Bragg raster, promptly holographic wrting method, and light writes from the side of optical fiber, utilizes the coherence of light directly to form interference fringe on optical fiber.After 1993, people such as K.O.Hill have proposed phase mask method (Phasemask) in succession, point-to-point writing method (Point-by-point) [4] and scanning wrting method.
Holographic wrting method has been broken through the restriction of vertical standing wave method to the Bragg wavelength, but it has proposed higher requirement to the coherence of light source, also difficulty relatively in the adjustment.The manufacture difficulty of fiber grating has been simplified in the proposition of phase mask method greatly, has improved development efficient.The precision and the homogeneity of grating mainly guarantee by phase mask, all do not have very high requirement to the coherence of light source with to the stability of experimental provision.But the grating cycle of producing, a template can only be used for a specific centre wavelength by the decision of the grating cycle on the template.This is for its application in the division multiplex fibre-optic communication wave system very big restriction beyond doubt.Although people have found out some centre wavelength method for trimming, as gradient method and pulling method, its effect far from ideal.Make fiber grating with mask means and need prepare the mask plate in a lot of different grating cycles, to tens thousand of dollars, this is impracticable under the economic capability condition of limited to price thousands of.Point-to-point writing method does not need to use template, and it is to make to write light beam and move axially along optical fiber, controls the break-make and the Strength Changes of light simultaneously, thereby required grating pattern is write on the optical fiber.Obviously, as long as gated sweep speed and light intensity just can obtain grating cycle, chirp value and apodizing function arbitrarily, thereby obtain desirable spectral characteristic.But, realize that difficulty is big to the accuracy requirement height of existing machinery device.
The scanning wrting method has appearred in the advantage in conjunction with phase mask method and point-to-point writing method two aspects.People such as nineteen ninety-five W.H.Loh roll up the 20th phase (W.H.Loh. at the optics journal the 20th in 95 years, et al., Optics Letters, 20 (20), 2051 (1995)) propose to utilize the tuning scanning method of piezoelectric ceramics (PZT), this experimental provision as shown in Figure 1, among the figure: frequency multiplication Ar+ ion laser 244nm light source 11 through scanning mirror 12 reflected illumination on phase mask 13, template is close to by optical fiber 14 and two is fixed on the micro-processor controlled PZT scanning mobile platform 15, and it is that 5nm, the linearity are the displacement of ± 0.5,20 μ m that the PZT platform can produce error.The method of making grating with this device is: scanning mirror is at the uniform velocity to move, and its speed is to pre-set, and can't accomplish has different rate values at diverse location.When scanning mirror moved, the last added voltage of PZT was with the position change of exposure station, just makes optical fiber be subjected to shake in various degree in different places.In optical fiber middle part amount of jitter minimum, two ends amount of jitter maximum, original so uniform exposure is distributed on the optical fiber with regard to uneven, thereby can obtain cutting the fiber grating of toe.Adopt this method, can obtain 6mm long cut the toe fiber grating.Empirical curve as shown in Figure 2.Among the figure: X-axis is wavelength shift (nm), and Y-axis is reflectivity (dB), the reflectance spectrum curve of the solid line among the figure for obtaining in the experiment, and dotted line is the reflectance spectrum curve that Theoretical Calculation obtains, the about 0.3nm of fiber grating three dB bandwidth that obtains in the experiment, side mode suppression ratio 40dB.
Though this method has realized high side mode suppression ratio, can find out from its reflectance spectrum curve; Reflectance spectrum curve top is also uneven, and reflection bandwidth is narrower; And must scanning mirror and the PZT platform move simultaneously, cooperatively interact, control accuracy requires high, the experimental provision complexity realizes that difficulty is big.
The objective of the invention is for overcoming the weak point of prior art, a kind of warbling and the adjustable fiber grating method for making of apodizing function proposed, adopting argon ion frequency multiplication continuous wave laser is light source, use uniform phase mask, by the different software of operation on microcomputer, control and dynamic sweep velocity and the exposure of adjusting light beam, can on the standard single-mode fiber that hydrogen carries, produce and have high reflectance, high side mode suppression ratio, the grating of reflectance spectrum flat-top band broad, with the different apodizing function of setting of software input, can make different gratings, make the present invention simpler, economical, practical, be easy to realize having good repeatability and dirigibility.Be convenient to business enterprise expand application at home.
A kind of the warbling and the adjustable fiber grating method for making of apodizing function that the present invention proposes may further comprise the steps:
1) adopt continuous ultraviolet laser device as light source;
2) scanning reflection mirror that will have a function of scanner uni folded light beam is fixed on the scanning mobile platform, and this scanning mobile platform links to each other with the PIO mouth of microcomputer;
3) light-sensitive optical fibre is fixed on the appropriate location, makes its hot spot that can receive the scanning reflection mirror reflection, and near an even phase mask is set before this optical fiber;
4) set the apodizing function parameter by online input, the motion state of coming the gated sweep mobile platform with the software that is stored in the microcomputer, make it according to this apodizing function curve symmetrical distribution rule operation, and the drive scanning reflection mirror scans said optical fiber, then the exposure of optical fiber each point distributes by this function curve, obtains required warble and cutting the toe fiber grating.
The present invention changes movement velocity, run duration, the move distance of scanning mobile platform by the different apodizing function of input, both can produce different warble and cut the toe fiber grating.
Method of the present invention is with the existing difference of the tuning scanning method of piezoelectric ceramics that adopts:
When the present invention was based on the optical fiber every bit place scan speed change, the residence time was different, thereby suffered exposure also changes, and with sweep velocity complementary relationship was arranged.Promptly, must make the change curve of sweep velocity and the curve of exposure be symmetrical distribution so if to make optical fiber be along a certain curvilinear motion in axial exposure.For example, be to change if make optical fiber in axial exposure by Gaussian curve, should make the change curve of sweep velocity and Gaussian curve be symmetrical distribution so.Gauss's apodizing function curve as shown in Figure 3, X-axis is time (min), Y-axis is normalized intensity (a.u.).Fig. 4 is the change curve of corresponding sweep velocity with it, and X-axis is time (min), and Y-axis is normalized intensity (a.u.), and the optical fiber that obtains also is to change by Gaussian curve in axial exposure.Certainly will make optical fiber is to change along other different function curve in axial exposure, then makes get final product corresponding with it of change curve of sweep velocity.The present invention adopts in the enterprising line program design of microcomputer, uses micro-processor controlled scanning mobile platform of software-driven, the catoptron that folded light beam is arranged on this platform, by online input apodizing function parameter, thereby dynamically adjust the sweep velocity and the exposure of light beam by system controlled by computer, obtain different fiber gratings at last.
The principle that the present invention adopts is as follows:
Evenly optical fiber Bragg raster has the modulation of strict periodic refractive index uniformly, its Bragg centre wavelength
λ
B=2 Λ n
EffWherein, L is the cycle of grating, and neff is the effective refractive index of optical fiber.As long as change optical fibre refractivity, just can change the centre wavelength of fiber grating, thereby obtain the fiber grating of different performance requirement.
For suppressing the secondary lobe of fiber grating reflectance spectrum, must adopt apodization in the present invention, principle is as follows: with optical grating reflection rate ρ=σ e
J (2 δ=-), the substitution Riccati differential equation:
ρ=j (ρ+j κ (1+ ρ of 2 δ-)
2) can obtain
σ '=jk[e
-j (2 δ z-)+ σ
2e
J (2 δ z-)] wherein: σ is a reflectivity amplitude, and δ is the off resonance amount, and is a raster phase.To antiradar reflectivity grating, σ
2Item can be ignored, and has
This shows, does not consider phase factor, and amplitude reflectivity r (d) in fact is exactly the Fourier conversion of coupling coefficient distribution function.If the just suffered exposure of the coupling coefficient of grating gradually changes along the length direction of grating, make to level off to zero gradually at the two ends of grating, just can improve the characteristic of grating.Coupling coefficient can be selected Blackman, Hamming, Gauss, Tanh, Sinc, functions such as Cauchy for use.
Characteristics of the present invention:
The present invention is by the software of establishment, can change the motion state of scanning mobile platform, accurately control its velocity variations, make it according to required function motion, just can obtain high reflectance, high side mode suppression ratio, have certain reflection bandwidth scope, warble and fiber grating that apodizing function is adjustable.This method is fixed optical fiber, relies on the motion of catoptron, changes the exposure of optical fiber, thereby makes that the device of making grating is simple, economic, practical, easy to operate, has good repeatability and dirigibility.
The accompanying drawing simple declaration:
Fig. 1 is the tuning scanning method Experimental equipment of existing piezoelectric ceramics (PZT).
Fig. 2 is existing experimental curve diagram.
Fig. 3 is existing Gauss's apodizing function curve.
Fig. 4 is the change curve of sweep velocity of the present invention.
Fig. 5 is a fiber grating square law device synoptic diagram of the present invention.
Fig. 6 is a reflectance spectrum curve map of the present invention.
Fig. 7 is the toe fiber grating point by point scanning Control Software process flow diagram of cutting of the present invention.
Of the present invention warble and the adjustable fiber grating method for making embodiment of apodizing function be described with reference to the accompanying drawings as follows:
The device of present embodiment preparing grating method as shown in Figure 5.Wherein, light source adopts continuous 244nm frequency multiplication Argon ion laser 21 (production of U.S. coherent company).Scanning reflection mirror 22 is fixed on the ESP6000 scanning mobile platform (production of Newport company) 23, and scanning mobile platform kinematic accuracy is 0.1mm.Catoptron 22 has the function of scanner uni folded light beam, and the ultraviolet light that laser instrument 21 is exported reflexes on the even phase mask 24, this phase mask length is 25mm, and ultraviolet light is radiated at carrying on the standard single-mode fiber 25 of processing through hydrogen under it through phase mask.ESP6000 scanning mobile platform links to each other with the PIO mouth (not shown) of microcomputer.By the drive software that operation on microcomputer designs in advance, change the motion state (movement velocity, run duration, move distance) of mobile platform, it is moved according to a certain characteristics of motion, just can obtain different fiber gratings.
In the whole process of making, adopting spectrum width is that wide spectrum light source 27, circulator 26 and the precision of 25nm is that the AQ-6315B spectrometer 28 of 0.05nm carries out the test of grating performance, reflectance spectrum and transmitted spectrum to fiber grating are analyzed, and can obtain the performance parameter of fiber grating.
The main technique flow process of present embodiment is as follows:
1. optical fiber is carried hydrogen and handle and peel off coat long about about 30mm;
2. after optical fiber being fixed on even phase mask plate, making it to try one's best but do not stick;
3. adjust the luminous power of laser instrument to the about 100mW of output;
4. adjust light path, the hot spot through the scanning reflection mirror reflection is radiated on the fibre core of optical fiber;
5. open ESP 6000 systems of microcomputer, enter the working interface of software, and ESP 6000 is carried out initialization;
6. start the scanning mobile platform, make it can free movement;
7. side-play amount is set, makes the scanning mobile platform move to the reference position of cutting the toe motion;
8. total distance of toe motion is cut in input, maximum, minimum speed; Order scanning mobile platform begins to cut the toe motion, finishes until preparing grating.
Wherein, the software programming of gated sweep mobile platform motion state is:
Adopt Visual Basic 6.0 programming languages, on the basis of the dynamic data chained library (Dynamic Link Library) that ESP 6000 systems provide, worked out based on the toe fiber grating point by point scanning of cutting of Windows95 operating system and made software, be used for the variable motion of accurate gated sweep mobile platform, so that obtain the desirable toe fiber grating of cutting.This software workflow figure as shown in Figure 7.It mainly comprises following process:
1, initialization procedure: system is carried out initialization;
2, bug check process: read error information, and be presented at it in window one by one;
3, start scanning mobile platform process: open the scanning mobile platform, making it can free movement;
4, select to cut toe mode process: select required apodizing function, the scanning mobile platform can be moved by the mode of choosing, apodizing function is: Blackman, Hamming, Gauss, Tanh, Sinc, functions such as Cauchy, select the Gauss apodizing function in the present embodiment for use:
5, the scanning mobile platform process that makes zero: the initial position of choosing the scanning mobile platform;
6, parameter input process: parameters such as the speed that input is relevant, distance;
7, computation process: calculate scanning motion time and actual scanning length according to the apodizing function of choosing;
8, motion process: the driven sweep mobile platform is cut the toe motion.
9, withdraw from process: close the kinematic axis of scanning mobile platform, log off, finish manufacturing process.
This software can be monitored the state of scanning motion in real time, reads movement position and run duration in real time, and this method biggest advantage is exactly accurately, and is convenient.The kinematic error of scanning mobile platform is 0.1 micron.As long as input control corresponding parameter, just can be according to given maximum, minimum speed, parameters such as distance, precompute the run duration of scanning mobile platform in fiber grating manufacturing process, and the actual range of motion, so that the user can reasonably adjust maximum, the minimum speed of input, control the time shutter and the exposure of optical fiber, obtain the fiber grating of high-quality.
Adopt the method at interface to program, make it directly perceived, friendly.The instantaneous position and the time of scanning mobile platform can both clearly illustrate on the interface, be convenient to the user and monitor at any time.The interface is designed according to operating process, makes the user come into plain view.This program also has stronger interactivity, wherein is provided with a lot of prompting frames and help window especially, and guides user is correctly used this software.
The reflectance spectrum that the typical optical fiber grating that utilizes present embodiment to make provides as shown in Figure 6.It has shown good warble and cuts the toe characteristic.Fig. 6 has provided its reflectance spectrum curve, and X-axis is wavelength (nm), and Y-axis is reflectivity (dB), side mode suppression ratio: 25dB, reflectance spectrum flat-top bandwidth: 0.6nm.Have cutting the toe fiber grating and will being applied in the optical add-drop multiplexer (Optical Add/Drop Multiplexer) of certain reflection bandwidth scope.
Claims (3)
1, a kind of warbling and fiber grating method for making that apodizing function is adjustable may further comprise the steps:
1) adopt continuous ultraviolet laser device as light source;
2) scanning reflection mirror that will have a function of scanner uni folded light beam is fixed on the scanning mobile platform, and this scanning mobile platform links to each other with the PIO mouth of microcomputer;
3) light-sensitive optical fibre is fixed on the appropriate location, makes its hot spot that can receive the scanning reflection mirror reflection, and near an even phase mask is set before this optical fiber;
4) set the apodizing function parameter by online input, the motion state of coming the gated sweep mobile platform with the software that is stored in the microcomputer, make it according to this apodizing function curve symmetrical distribution rule operation, and the drive scanning reflection mirror scans said optical fiber, then the exposure of optical fiber each point distributes by this function curve, obtains required warble and cutting the toe fiber grating.
2, fiber grating method for making as claimed in claim 1 is characterized in that, said laser instrument is continuous 244nm frequency multiplication Argon ion laser.
3, fiber grating method for making as claimed in claim 1 is characterized in that, said scanning mobile platform is an ESP6000 scanning mobile platform.
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Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
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CN100371751C (en) * | 2006-03-03 | 2008-02-27 | 清华大学 | Method for producing non-linear chirp optical fibre grating for 40 Gb/S optical communication system |
CN100437168C (en) * | 2007-12-06 | 2008-11-26 | 西安盛佳光电有限公司 | Manufacturing method of polarization maintaining optical fiber apodization double gratings |
CN100456064C (en) * | 2006-12-28 | 2009-01-28 | 北京交通大学 | High-order golden section Hamming function apodizing edition and method for making chirp optical fiber grating |
CN111308607A (en) * | 2018-12-12 | 2020-06-19 | 上海科乃特激光科技有限公司 | Fiber grating apodization device and operation method thereof |
CN111856644A (en) * | 2020-07-28 | 2020-10-30 | 中国人民解放军国防科技大学 | Apodization long period optical fiber grating inscribing device, inscribing method and laser system |
CN115954749A (en) * | 2023-03-09 | 2023-04-11 | 山东省科学院激光研究所 | Single-frequency laser |
Families Citing this family (1)
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CN100395572C (en) * | 2007-06-18 | 2008-06-18 | 西安盛佳光电有限公司 | Polarization maintaining fiber apodization grating production method |
-
2000
- 2000-06-23 CN CN00109436A patent/CN1105924C/en not_active Expired - Fee Related
Cited By (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN100371751C (en) * | 2006-03-03 | 2008-02-27 | 清华大学 | Method for producing non-linear chirp optical fibre grating for 40 Gb/S optical communication system |
CN100456064C (en) * | 2006-12-28 | 2009-01-28 | 北京交通大学 | High-order golden section Hamming function apodizing edition and method for making chirp optical fiber grating |
CN100437168C (en) * | 2007-12-06 | 2008-11-26 | 西安盛佳光电有限公司 | Manufacturing method of polarization maintaining optical fiber apodization double gratings |
CN111308607A (en) * | 2018-12-12 | 2020-06-19 | 上海科乃特激光科技有限公司 | Fiber grating apodization device and operation method thereof |
CN111856644A (en) * | 2020-07-28 | 2020-10-30 | 中国人民解放军国防科技大学 | Apodization long period optical fiber grating inscribing device, inscribing method and laser system |
CN111856644B (en) * | 2020-07-28 | 2023-10-03 | 中国人民解放军国防科技大学 | Apodized long-period fiber bragg grating inscription device, inscription method and laser system |
CN115954749A (en) * | 2023-03-09 | 2023-04-11 | 山东省科学院激光研究所 | Single-frequency laser |
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