CN1479122A - Dynamic optical gain equalizer - Google Patents
Dynamic optical gain equalizer Download PDFInfo
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- CN1479122A CN1479122A CNA031343678A CN03134367A CN1479122A CN 1479122 A CN1479122 A CN 1479122A CN A031343678 A CNA031343678 A CN A031343678A CN 03134367 A CN03134367 A CN 03134367A CN 1479122 A CN1479122 A CN 1479122A
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- optical fiber
- birefringece crystal
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Abstract
A dynamic optical gain equalizer is composed of optical circulator, optical wave merge-division unit, optical fibre collimator, two birefractive crystals whose optical axises are perpendicular, magneto-optical polarization control unit and full reflection end of optical fibre. Different voltages are applied to different wavelengthes by the magneto-optical polarization control unit to generate different attenuations, so equalizing their gains.
Description
One, affiliated technical field
The invention belongs to fiber optic communication field, be specifically related to a kind of unbalanced dynamic gain of light balanced device of power that is used for compensating the dense wave division multipurpose optical fiber telecommunications system.
Two, background technology
Along with the mankind enter information society, optical fiber communication has entered the unprecedented high-speed developing period, and gradually to all optical network Communication Development, Networks of Fiber Communications is the core of following information infrastructure.
The development of the Internet (Internet) has proposed very high requirement to the transmission capacity of communication system, adopt time-division multiplex technology to improve capability of communication system, when transfer rate reaches 40Gb/s,, further improve just very difficult more substantially near the rate limit of electron device.Dense wave division multipurpose (DWDM-Dense Wavelength Division Multiplexing) becomes the only way of Tb/s light transmission, and newly-built trunk fiber communication system has all adopted the DWDM technology at present.
In the DWDM optical transmission system, because the gain or the loss of devices such as Erbium-Doped Fiber Amplifier (EDFA) (EDFA), Transmission Fibers, optical filter, dispersive compensation element are relevant with wavelength, thus generally in the optical transmission chain power of each wavelength channel be unbalanced.Although the static filter that adopt realize the planarization that gains more in fiber amplifier, residual unbalancedly will constantly accumulate amplification along with the increase of cascaded link; On the other hand,, the Add/drop Voice Channel in the optical-fiber network, reconfigure or reason such as network recovery along with DWDM develops to dynamic configurable networked direction, also can make occur between the passage serious unbalanced.
The lack of uniformity of channel power meeting severe exacerbation network performance in the optical-fiber network, a kind of gainequalizer that can adapt to power dynamics in the optical fiber link---DGE (DGE-Dynamic Gain Equalizer) satisfies the requirement of DWDM optical-fiber network therefore to press for development.
Find by literature search: United States Patent (USP) 6493502 (Dec.10,2002) a kind of technology of utilizing waveguide to realize light power equalization has been proposed, promptly utilize waveguide to form a series of asymmetric mach pool moral interferometer, change the transmission of waveguide by the thermo-optic effect of waveguide, make each Mach Zehnder interferometer produce the required interference of light, after synthetic, produce required decay spectra, thereby realize gain balance.This scheme need accurately be controlled technical sophistication simultaneously to a plurality of waveguides.Because what adopt is thermo-optic effect, so response speed is slower, is 20-100ms.
United States Patent (USP) 6498872 (Dec.24,2002) a kind of liquid crystal reflection grating technology has been proposed, its basic functional principle is to utilize body grating will import light according to certain spectral resolution demultiplexing, use each pixel of electrically-controlled liquid crystal to rotate the damping capacity that changes input light again, produce the decay relevant, thereby realize power equalization with optical wavelength.This scheme is subjected to the influence of environment temperature bigger owing to liquid crystal property, thus generally temperature control equipment to be arranged, and response speed of liquid crystal is slower, reaches 100ms.
Three, summary of the invention
Defective or deficiency at above-mentioned prior art exists the objective of the invention is to, and propose a kind of new DGE.This DGE has that power regulates the speed soon, regulates that dynamic range is big, good stability, simple, the low cost and other advantages of processing technology.
The technical solution that realizes above-mentioned purpose is as follows:
DGE is made of optical circulator, optical multiplexing/demultiplexing unit, optical fiber collimator, birefringece crystal, magneto-optic Polarization Control unit, optical fiber total reflection end.
The light that enters DGE at first passes through optical circulator, enters the optical multiplexing/demultiplexing unit again.The optical multiplexing/demultiplexing unit adopts chromatic dispersion element such as grating or multilayered medium film method to make each wavelength channel demultiplexing, makes the light of each wavelength channel enter first birefringece crystal again.Because that the birefringence effect of crystal, the light of each wavelength are divided into is that separate the direction of propagation, the orthogonal o light in polarization direction and e light.The light that first birefringece crystal comes out enters magneto-optic Polarization Control unit, and magneto-optic Polarization Control unit by using Faraday effect is rotated the polarisation of light direction.According to alive difference on the pairing magneto-optic Polarization Control of each wavelength unit, the rotation amount difference of the polarization direction of each wavelength light.The light that magneto-optic Polarization Control unit comes out enters second birefringece crystal, and the material of two birefringece crystals, thickness, cut direction are all identical, but makes its light shaft positive cross when installing.Magneto-optic Polarization Control unit is not during making alive, the o light and the e polarisation of light direction of the first birefringece crystal outgoing are constant, the o light of first birefringece crystal becomes the e light of second birefringece crystal, the e light of first birefringece crystal becomes the o light of second birefringece crystal, pools a branch of light after o light that separately transmits in first birefringece crystal and the birefringence of e light through second birefringece crystal.During magneto-optic Polarization Control unit making alive, the polarisation of light direction that first birefringece crystal is come out because of the Faraday effect of magneto-optical crystal rotates to an angle, then the o light of its second birefringece crystal that the neutralizes light component consistent with the e light polarization direction pools a branch of light after through second birefringece crystal, effectively in the coupled into optical fibres collimating apparatus.Remaining light component through second birefringece crystal after the direction of propagation distance of separating bigger, can't the coupled into optical fibres collimating apparatus in, this part luminous energy can lose.According to the alive difference in magneto-optic Polarization Control unit of each wavelength channel correspondence, the rotation amount difference of light polarization direction, the luminous energy loss of each wavelength channel is also different.
The end of the optical fiber collimator tail optical fiber that the emergent light of second birefringece crystal enters is coated with total reflection film, the light that enters optical fiber collimator can all reflect the reverse transmission of beginning, same beam separation, polarization direction rotation take place, converge and the loss process in reverse transmission light and forward transmitted light, be the exchange function of first birefringece crystal and second birefringece crystal: reverse transmission light at the second birefringece crystal place separately, part light is depleted at the first birefringece crystal place, and another part light pools a branch of optically-coupled and advances optical fiber collimator.The light of reverse each wavelength channel that returns is left DGE by the unit multiplexed optical circulator that enters of optical multiplexing/demultiplexing together by the outlet of optical circulator, enters in the dwdm system and transmits.
According to dwdm system the requirement of each wavelength channel power is applied different dynamic electric voltages to corresponding each magneto-optic Polarization Control unit, make each wavelength channel produce different decay, just can realize the Dynamic Gain Equalizer function of system.
Dynamic gain of light balanced device of the present invention adopts full Electromagnetic Control, so the power adjustment is very fast, can reach the microsecond level, even the submicrosecond level.And luminous power dynamic adjustments scope is big, good stability.Simultaneously, element of the present invention all can adopt simple common process manufacturing, and production cost is lower.
Four, description of drawings
Fig. 1 is DGE general structure and the light positive synoptic diagram to the transmission light path;
Fig. 2 is the synoptic diagram of reverse transmission light in the gainequalizer;
Fig. 3 is the transmission synoptic diagram of a wavelength channel in first birefringece crystal;
Fig. 4 is the not synoptic diagram of making alive time by magneto-optic Polarization Control unit of magneto-optic Polarization Control unit;
Fig. 5 is the synoptic diagram of magneto-optic Polarization Control unit making alive time by magneto-optic Polarization Control unit;
Fig. 6 is the not synoptic diagram of making alive time by second birefringece crystal of magneto-optic Polarization Control unit;
Fig. 7 is the synoptic diagram of magneto-optic Polarization Control unit making alive time by second birefringece crystal;
Fig. 8 is the synoptic diagram that magneto-optic Polarization Control unit changes light polarization direction.
Five, embodiment
Below in conjunction with accompanying drawing technical scheme of the present invention is further described.
As shown in Figure 1, according to technical scheme of the present invention, the DGE one-piece construction mainly comprises: the optical fiber collimator 3 of optical circulator 1, optical multiplexing/demultiplexing unit 2, first birefringece crystal, first birefringece crystal 4, magneto-optic Polarization Control unit 5, second birefringece crystal 6, the optical fiber collimator 7 of second birefringece crystal, the tail optical fiber 8 of optical fiber collimator, the total reflection end 9 of optical fiber.
Each wavelength channel all there are corresponding optical fiber collimator 3,7 and magneto-optic Polarization Control unit 5.The both sides of the magneto-optical crystal 15 (referring to Fig. 4) in first birefringece crystal 4, second birefringece crystal 6, the magneto-optic Polarization Control unit all are coated with anti-reflection film, to reduce the insertion loss of DGE.The material of first birefringece crystal 4 and second birefringece crystal 6, thickness, cut direction are all identical, but make the optical axis of two birefringece crystals become 90 ° when installing.
The light path of light forward transmitted in DGE has been shown among Fig. 1, being light enters optical circulator 1 from the inlet fiber active linker 10 of DGE, the emergent light of optical circulator 1 enters optical multiplexing/demultiplexing unit 2, the 2 couples of multiplexing light wavelength channel λ together in optical multiplexing/demultiplexing unit
1, λ
2... λ
nCarry out demultiplexing, the light of each wavelength enters each self-corresponding optical fiber collimator 3, optical fiber collimator enters first birefringece crystal 4 after the emergent light of optical fiber is become quasi-parallel light, because the birefringence effect of crystal 4, the light of each wavelength are divided into the direction of propagation o light 12 and e light 13 (referring to Fig. 3) that separate, that the polarization direction is vertical.The emergent light of first birefringece crystal 4 enters magneto-optic Polarization Control unit 5, applies certain voltage on the magnetizing coil 16 of magneto-optic Polarization Control unit 5, because the Faraday effect of magneto-optical crystal, the polarization direction of light beam 12,13 can rotate to an angle.The emergent light of magneto-optic Polarization Control unit 5 enters second birefringece crystal 6, and light beam 12,13 is through the birefringence effect of second birefringece crystal 6, and a part of light pools a branch of light, and coupled into optical fibres collimating apparatus 7 is through the total reflection end 9 of optical fiber 8 arrival optical fiber.Light in the optical fiber is all reflected at total reflection end 9, beginning reverse transmission in gainequalizer.It is big that the spacing of the transmission direction of another part light further becomes, and can not enter optical fiber collimator 7 and lose.According to 5 the making alive differences in the pairing magneto-optic Polarization Control of each wavelength channel unit, the rotation amount difference of light polarization direction, the light decrement of each wavelength channel is also different.
Fig. 2 shows the situation that the reverse transmission light that reflected by optical fiber total reflection end 9 transmits in DGE.Same beam separation, polarization direction rotation take place, converge and the loss process in reverse transmission light and forward transmitted light, be the exchange function of first birefringece crystal 4 and second birefringece crystal 6: second birefringece crystal 6 makes beam separation in reverse transmission light, first birefringece crystal 4 makes the part optically-coupled advance optical fiber collimator 3, and another part light loss consumes.Each wavelength X of coupled into optical fibres collimating apparatus 3
1, λ
2... λ
nReverse transmission light enter optical multiplexing/demultiplexing unit 2, optical multiplexing/demultiplexing unit 2 carries out each wavelength channel multiplexing, light after multiplexing enters optical circulator 1, arrives the outlet fiber active linker 11 of DGE by the outlet of optical circulator 1, enters the dwdm system transmission.
Situation when the forward transmitted light that Fig. 3 shows a wavelength channel in first birefringece crystal 4 birefringence takes place.Birefringece crystal can be selected vanadic acid yttrium (YVO for use
4), kalzit (CaCO
3) or rutile (TiO
2) the single axial birefringence crystal, more suitable from the combination property yttrium vanadate crystal.The optical axis 14 of crystal becomes the θ angle with plane of crystal.The incident light of vertical plane of crystal can be divided into two bundles separately the o light 12 and the e light 13 of transmission because birefringent phenomenon takes place in crystal, o light 12 and e light 13 are complete polarized lights, and the polarization direction is orthogonal.The vertical paper of o polarisation of light direction, e polarisation of light direction is in paper.
Fig. 4,5 shows the structure of a magneto-optic Polarization Control unit 5.The 15th, magneto-optical crystal, the MAGNETIC GARNET FILMS GROWN that can select for use yttrium iron garnet crystal (YIG), bismuth calcium vanadium iron garnet crystal (BCVIG) or bismuth to mix, the Faraday effect of BCVIG and bismuth doped garnet monocrystal thin films should preferentially be selected for use greater than yig crystal.The 16th, magnetizing coil, the 17th, coil rack.Fig. 4 is the situation of magnetizing coil 16 when not having making alive, and this moment is constant by the polarization direction of the light beam 12,13 of magneto-optic Polarization Control unit.Situation when Fig. 5 is magnetizing coil 16 making alives, on magnetizing coil 16, apply certain voltage, produce corresponding magnetic field at the coil core, magneto-optical crystal makes the polarization direction of light beam 12,13 rotate a certain angle under the effect in magnetic field, so from the two-beam that magneto-optic Polarization Control unit comes out, each bundle had all both contained the polarized component of vertical paper, contained the polarized component in the paper again.
Fig. 6 shows the not transmission situation of making alive time in second birefringece crystal 6 of magneto-optic Polarization Control unit 5.Because two birefringece crystals are all identical on material, thickness, crystal-cut direction, just make the optical axis of the two become 90 ° when mounted, so the o light of first birefringece crystal becomes the e light of second birefringece crystal, the e light of first birefringece crystal becomes the o light of second birefringece crystal.The light beam 12,13 that is separated by first birefringece crystal can transmit in the coupled into optical fibres collimating apparatus 7 through pooling a branch of light after the birefringence of second birefringece crystal again.
When Fig. 7 showed magneto-optic Polarization Control unit 5 making alives, birefringent situation took place in light beam 12,13 in second birefringece crystal 6.Because the Faraday effect of magneto-optic Polarization Control unit 5, the polarization direction of light beam 12,13 rotates, and incides the polarized component that each bundle in the two-beam of crystal 6 had all both contained vertical paper, contains the polarized component in the paper again.As shown in Figure 7, the vertical paper polarized component 21 in polarized component 19 and the light beam 12 pools a branch of light 22, transmission in the light beam 22 coupled into optical fibres collimating apparatuss 7 because of the birefringence effect of crystal 6 in the paper in the light beam 13.Polarized component 20 is because of the birefringence effect of crystal 6 in vertical paper polarized component 18 in the light beam 13 and the paper in the light beam 12, and the distance that transmission direction separates is bigger, can't enter optical fiber collimator 7 and loses.
Fig. 8 shows the situation of change of the light polarization direction of being drawn in face of the forward transmitted light direction.Light is broken down into two-beam A, the B of vertical polarization and horizontal polarization after through first birefringece crystal 4, on magneto-optic Polarization Control unit 5, apply certain voltage, light beam A, B have rotated the β angle through 5 rear polarizer aspects, magneto-optic Polarization Control unit, become light beam A ', B ', light beam A then ' pooled a branch of light at the component Bx ' of X-direction by second birefringece crystal 6 at the component A y ' and the light beam B ' of Y direction, transmission (referring to Fig. 7) in the optical fiber collimating apparatus 7 of going forward side by side; Light beam A ' be depleted at the component By ' of Y direction at the component A x ' and the light beam B ' of X-direction.
Claims (7)
1, a kind of DGE, it is characterized in that this DGE comprises: the total reflection end [9] of the incident optical collimating apparatus [7] of the incident optical collimating apparatus [3] of optical circulator [1], optical multiplexing/demultiplexing unit [2], first birefringece crystal, first birefringece crystal [4], magneto-optic Polarization Control unit [5], second birefringece crystal [6], second birefringece crystal, the tail optical fiber [8] of optical fiber collimator, optical fiber;
Light enters optical circulator [1] from the inlet fiber active linker [10] of DGE, and the emergent light of optical circulator [1] enters optical multiplexing/demultiplexing unit [2], and optical multiplexing/demultiplexing unit [2] are to multiplexing light wavelength channel λ together
1, λ
2... λ
nCarry out demultiplexing, the light of each wavelength enters each self-corresponding optical fiber collimator [3], optical fiber collimator enters first birefringece crystal [4] after the emergent light of optical fiber is become quasi-parallel light, the emergent light of first birefringece crystal [4] enters magneto-optic Polarization Control unit [5], on the magnetizing coil [16] of magneto-optic Polarization Control unit [5], apply voltage and change the polarisation of light direction, the emergent light of magneto-optic Polarization Control unit [5] enters second birefringece crystal [6], birefringence effect through second birefringece crystal [6], part light pools a branch of light, coupled into optical fibres collimating apparatus [7] is through the total reflection end [9] of optical fiber [8] arrival optical fiber; Light in the optical fiber is all reflected at total reflection end [9], beginning reverse transmission in gainequalizer.
2, DGE according to claim 1 is characterized in that, described two birefringece crystals [4] and [6] are uniaxial crystal, and the material of crystal, thickness, cut direction are the same, but makes the optical axis of two crystal become 90 ° when installing; Light positive is when transmission, first birefringece crystal [4] all is divided into polarization direction two-beam vertical, that separate the certain distance transmission with the light of each wavelength channel, second birefringece crystal [6] advances optical fiber collimator [7] with a part of optically-coupled, and another part light loss consumes; To reverse transmission light, the exchange function of first birefringece crystal [4] and second birefringece crystal [6].
3, DGE according to claim 1 is characterized in that, described magneto-optic Polarization Control unit [5] adopts magneto-optical crystal [15] and magnetizing coil [16] rotation polarisation of light direction; The pairing magnetizing coil of different wavelengths of light [16] institute making alive difference, the rotation amount difference of light polarization direction, thus the optical energy attenuation amount of each wavelength is also different.
4, DGE according to claim 1 is characterized in that, the total reflection end [9] of described optical circulator [1] and optical fiber makes light forward and reverse twice transmission in DGE.
5, this DGE according to claim 1 is characterized in that, described total reflection end [9] is to constitute at the end of optical fiber collimator tail optical fiber plating total reflection film, and the light in the optical fiber is all reflected back at total reflection end [9].
6, DGE according to claim 1 is characterized in that, the both sides of described first birefringece crystal [4], second birefringece crystal [6] all are coated with anti-reflection film.
7, DGE according to claim 3 is characterized in that, the both sides of described magneto-optical crystal [15] all are coated with anti-reflection film.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNA031343678A CN1479122A (en) | 2003-07-07 | 2003-07-07 | Dynamic optical gain equalizer |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNA031343678A CN1479122A (en) | 2003-07-07 | 2003-07-07 | Dynamic optical gain equalizer |
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| CN1479122A true CN1479122A (en) | 2004-03-03 |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102216832A (en) * | 2008-12-26 | 2011-10-12 | 住友大阪水泥股份有限公司 | Optical modulator |
| CN106301489A (en) * | 2015-06-26 | 2017-01-04 | 深圳市中兴微电子技术有限公司 | link equalization method and device |
-
2003
- 2003-07-07 CN CNA031343678A patent/CN1479122A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102216832A (en) * | 2008-12-26 | 2011-10-12 | 住友大阪水泥股份有限公司 | Optical modulator |
| CN106301489A (en) * | 2015-06-26 | 2017-01-04 | 深圳市中兴微电子技术有限公司 | link equalization method and device |
| CN106301489B (en) * | 2015-06-26 | 2019-10-18 | 深圳市中兴微电子技术有限公司 | Link equalization method and device |
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