CN117031794B - Dynamic channel equalization filter and optical fiber communication system - Google Patents
Dynamic channel equalization filter and optical fiber communication system Download PDFInfo
- Publication number
- CN117031794B CN117031794B CN202311296638.XA CN202311296638A CN117031794B CN 117031794 B CN117031794 B CN 117031794B CN 202311296638 A CN202311296638 A CN 202311296638A CN 117031794 B CN117031794 B CN 117031794B
- Authority
- CN
- China
- Prior art keywords
- light
- optical
- cylindrical lens
- polarization
- electro
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 239000013307 optical fiber Substances 0.000 title claims abstract description 36
- 238000004891 communication Methods 0.000 title claims abstract description 11
- 230000010287 polarization Effects 0.000 claims abstract description 102
- 230000003287 optical effect Effects 0.000 claims abstract description 96
- 239000013078 crystal Substances 0.000 claims abstract description 8
- 239000000919 ceramic Substances 0.000 claims description 17
- ZBSCCQXBYNSKPV-UHFFFAOYSA-N oxolead;oxomagnesium;2,4,5-trioxa-1$l^{5},3$l^{5}-diniobabicyclo[1.1.1]pentane 1,3-dioxide Chemical compound [Mg]=O.[Pb]=O.[Pb]=O.[Pb]=O.O1[Nb]2(=O)O[Nb]1(=O)O2 ZBSCCQXBYNSKPV-UHFFFAOYSA-N 0.000 claims description 13
- 239000000835 fiber Substances 0.000 claims description 5
- 238000007493 shaping process Methods 0.000 claims description 5
- 239000006185 dispersion Substances 0.000 claims description 3
- GQYHUHYESMUTHG-UHFFFAOYSA-N lithium niobate Chemical compound [Li+].[O-][Nb](=O)=O GQYHUHYESMUTHG-UHFFFAOYSA-N 0.000 claims description 2
- 230000007480 spreading Effects 0.000 claims description 2
- 230000008859 change Effects 0.000 abstract description 14
- 230000004044 response Effects 0.000 abstract description 2
- 230000002238 attenuated effect Effects 0.000 abstract 1
- 238000010586 diagram Methods 0.000 description 16
- 230000001276 controlling effect Effects 0.000 description 6
- 238000000034 method Methods 0.000 description 6
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 4
- 239000004973 liquid crystal related substance Substances 0.000 description 4
- 229910052710 silicon Inorganic materials 0.000 description 4
- 239000010703 silicon Substances 0.000 description 4
- 230000005540 biological transmission Effects 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 238000000411 transmission spectrum Methods 0.000 description 3
- 230000009471 action Effects 0.000 description 2
- 230000005684 electric field Effects 0.000 description 2
- 238000013459 approach Methods 0.000 description 1
- 230000033228 biological regulation Effects 0.000 description 1
- 238000004364 calculation method Methods 0.000 description 1
- 229910010293 ceramic material Inorganic materials 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 238000003780 insertion Methods 0.000 description 1
- 230000037431 insertion Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 230000000644 propagated effect Effects 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 230000003595 spectral effect Effects 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 239000010409 thin film Substances 0.000 description 1
Classifications
-
- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
- G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour
- G02F1/03—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour based on ceramics or electro-optical crystals, e.g. exhibiting Pockels effect or Kerr effect
- G02F1/0305—Constructional arrangements
-
- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
- G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour
- G02F1/03—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour based on ceramics or electro-optical crystals, e.g. exhibiting Pockels effect or Kerr effect
- G02F1/0305—Constructional arrangements
- G02F1/0311—Structural association of optical elements, e.g. lenses, polarizers, phase plates, with the crystal
-
- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
- G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour
- G02F1/03—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour based on ceramics or electro-optical crystals, e.g. exhibiting Pockels effect or Kerr effect
- G02F1/0327—Operation of the cell; Circuit arrangements
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
- H04B10/29—Repeaters
- H04B10/291—Repeaters in which processing or amplification is carried out without conversion of the main signal from optical form
- H04B10/293—Signal power control
- H04B10/2931—Signal power control using AGC
Abstract
The invention discloses a dynamic channel equalization filter and an optical fiber communication system, wherein the dynamic channel equalization filter comprises an optical front end and 4fA system and an optical engine; the optical front end is composed of an input/output optical fiber array, a micro lens array, a cylindrical lens, a Wollaston prism and a half-wave plate. The light spots at the output end of the optical fiber are shaped and expanded into elliptical light spots through the optical front end on the whole optical path, and polarization diversity is carried out to obtain two beams of linear polarized light with the same polarization state and a certain included angle. Two cylindrical lenses with orthogonal cambered surfaces deflect light beams, and the grating converts the light into wavesThe long diffraction spreads out and the optical engine can change the polarization state of the light, vary the amount of change for different wavelengths, and reflect the light back to the optical front. Since the optical front-end only allows light of a specific polarization state to pass through, the optical power is attenuated, and the balance of the optical power of different channels is realized. The invention adopts the optical engine driven by the electro-optical crystal, and can obtain faster response speed, smaller loss and lower cost.
Description
Technical Field
The invention belongs to the technical field of optical fiber communication, and particularly relates to a dynamic channel equalization filter and an optical fiber communication system.
Background
In order to meet the increasing demand of people for information, the transmission rate of optical fiber communication systems is increasing, and with the great application of dynamic optical switching devices such as reconfigurable optical add-drop multiplexer (ROAMD) and optical cross connect (OXC), optical fiber communication is developing from point-to-point transmission systems to intelligent dynamic all-optical networks, and optical fiber links become complicated and dynamically changed. Because the loss of the optical fiber in the optical network, the gain of the erbium-doped fiber amplifier (EDFA), the insertion loss of the Dispersion Compensation Module (DCM) and the gain and loss of other elements are different with different wavelengths, the power and the signal to noise ratio of each channel in the DWDM system are inconsistent, the transmission quality is seriously affected, and the compensation is needed.
The traditional compensation scheme is to use a Gain Flat Filter (GFF), and is generally classified into a thin film filter, a micro-light sine filter and a fiber grating filter. The transmission spectrum of the gain flattening filter is fixed and cannot be changed, and is difficult to use in more and more complex DWDM channels.
The novel gain flattening filter is required to have dynamic adjustable filtering capability, and mainly has two implementation approaches, one is to independently regulate and control each channel, and generally adopts a free space optical structure, the attenuation level of each channel is controlled through an optical engine, and the optical engine is generally composed of Liquid Crystal On Silicon (LCOS), so that the cost of the liquid crystal on silicon used by the scheme is high, and the structure is complex. The other is to perform integral control on the transmission spectrum, and a sine filter based on a multistage series structure is generally adopted. The spectral line is regulated and controlled through the phase adjustment of each stage, and the regulation and control of the whole transmission spectrum are realized through multistage serial connection. The scheme has large calculation capability requirement on the algorithm and the control chip.
Disclosure of Invention
Aiming at the defects of the prior art, the invention aims to provide a dynamic channel equalization filter and an optical fiber communication system, and aims to solve the problems of high cost and complex structure of the used silicon-based liquid crystal caused by the fact that an optical engine in the prior art consists of the silicon-based liquid crystal.
The invention provides a dynamic channel equalization filter, comprising: optical front end, 4fA system and an optical engine; the optical front end is used for shaping and expanding the light spot at the output end of the optical fiber into an elliptical light spot, and converting the input random polarized light into two linearly polarized light beams with the same polarization state and a certain included angle; 4fThe system is used for controlling the size of the light plate of the image plane to be consistent with the object plane, and spreading light according to wavelength dispersion through the grating of the focal plane; the optical engine adopts electro-optical crystal to realize dynamic gain compensation for unbalanced channel power.
Further, the optical engine comprises a half wave plate, a polarization splitting prism, electro-optic ceramics, a compensation block and a reflecting mirror; the linearly polarized light is rotated by 45 degrees through the half-wave plate, is divided into two beams of light with vertical polarization states through the polarization beam splitter prism, one beam of light is incident on the reflecting mirror after passing through the reflection and compensation block, and the other beam of light is continuously transmitted and incident on the electro-optical ceramic pressurized by the light passing surface.
The total optical path of the incident electrooptic ceramic can be changed by controlling the voltages of different units on the electrooptic ceramic pressurized by the light passing surface; the backward light after the phase delay of the electro-optical ceramic is converged with the reflected backward light and is combined by the polarization beam splitter prism, and the polarization state of the backward light after the combination is changed due to the phase delay of one beam of light.
Still further, the optical front-end includes: the device comprises an input/output optical fiber array, a micro lens array, a first cylindrical lens, a Wollaston prism and a half-wave plate; the input/output optical fiber array is used for fixing the angle and the position of input light; the micro lens array is used for expanding input light; the first cylindrical lens is used for shaping the round light spot into an elliptical light spot; the Wollaston prism is used for dividing input light into two light beams with different polarization states, only allowing light with a specific polarization state to return to the output port, and the proportion of the polarization state in reflected light directly corresponds to the power of the light returned to the output port, so that the balance of the power of different channels is realized; the half-wave plate is used to change the polarization state of light.
Further, 4fThe system comprises a second cylindrical lens, a third cylindrical lens, a grating, a fourth cylindrical lens and a fifth cylindrical lens; the second lens is used for forming 4fThe system realizes the control of the image plane light spots; the third cylindrical lens is used for deflecting the light beams to realize convergence and port switching; the grating is used for expanding the input light according to wavelength diffraction; the fourth cylindrical lens is used for deflecting the light beams to realize convergence and port switching; a fifth cylindrical lens for forming 4fThe system realizes the control of the focal spot on the image plane.
Still further, the electro-optic ceramic may be a lead magnesium niobate, lithium niobate, or KDP crystal. The lead magnesium niobate PMN-PT has larger electro-optic coefficient and smaller required control voltage compared with other materials.
When the optical axis direction of the lead magnesium niobate PMN-PT is the light passing surface direction, pressurizing the side surface of the lead magnesium niobate PMN-PT, wherein the PMN-PT is equivalent to a wave plate; the phase retardation differences in different polarization directions can be controlled by the magnitude of the applied voltage. When the optical axis direction of the lead magnesium niobate PMN-PT is the light-passing surface direction, pressurizing is carried out in the light-passing surface direction, and the refractive index of the PMN-PT changes and is equivalent to a phase retarder; the difference in phase delay between the front and rear passes can be controlled by the magnitude of the applied voltage.
The invention also provides an optical fiber communication system which comprises the dynamic channel equalization filter.
Compared with the prior art, the technical scheme of the invention has the advantages that the optical engine driven by the electro-optical crystal is adopted, the voltage control gain is used to obtain faster response speed, and the electro-optical crystal has better transparency and simple preparation, so that smaller loss and lower cost can be obtained.
Drawings
FIG. 1 is a schematic diagram of a first embodiment of the present invention;
FIG. 2 is a schematic structural view of a first embodiment of the present invention;
FIG. 3 is a schematic diagram of a second embodiment of the present invention;
FIG. 4 is a schematic diagram of a second embodiment of the present invention;
FIG. 5 is a polarization diversity structure applied in a device provided by an embodiment of the present invention; wherein, (a) is an optical path diagram of input light passing through a polarization diversity structure; (b) A light path diagram of the reflected light without changing the polarization state passing through the polarization diversity structure; (c) A light path diagram of the reflected light with pi phase changed for the polarization state passing through the polarization diversity structure;
FIG. 6 is a schematic diagram showing the change of polarization state in an optical engine according to a first embodiment of the present invention; wherein, (a) is a schematic diagram of the optical axis direction of the wave plate; (b) A polarization state change schematic diagram of the light inside the optical engine when the PMN-PT is not pressurized; (c) Pressurizing PMN-PT 0~V π/2 A polarization state change schematic diagram of light inside the optical engine; (d) Pressurizing V for PMN-PT π/2 A polarization state change schematic diagram of light inside the optical engine;
FIG. 7 is a schematic diagram showing the change of polarization state in an optical engine according to a second embodiment of the present invention; wherein, (a) is a schematic diagram of the optical axis direction of the wave plate; (b) A polarization state change schematic diagram of the light inside the optical engine when the PMN-PT is not pressurized; (c) Pressurizing PMN-PT 0~V π/2 A polarization state change schematic diagram of light inside the optical engine; (d) Pressurizing V for PMN-PT π/2 A polarization state change schematic diagram of light inside the optical engine;
FIG. 8 is a graph of channel attenuation versus applied voltage for the first embodiment of the present invention;
fig. 9 is a graph of channel attenuation versus applied voltage for a second embodiment of the present invention.
Detailed Description
The present invention will be described in further detail with reference to the drawings and examples, in order to make the objects, technical solutions and advantages of the present invention more apparent. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the invention.
The invention provides dynamic channel equalization filters of two different optical engines, which are mainly applied to optical fiber communication systems.
The principle of a first embodiment of the invention is shown in fig. 1, which consists of optical front ends 1, 4fSystem 2, optical engine 3. The optical front end 1 is composed of an input/output optical fiber array 11, a micro lens array 12, a first cylindrical lens 13, a Wollaston prism 14 and a half-wave plate 15. 4fThe system 2 consists of a second cylindrical lens 21, a third cylindrical lens 22, a grating 23, a fourth cylindrical lens 24 and a fifth cylindrical lens 25. The fourth cylindrical lens 24 is a mirror image of the third cylindrical lens 22 with respect to the grating, and the fifth cylindrical lens 25 is a mirror image of the second cylindrical lens 21 with respect to the grating. The optical engine 3 is composed of a half-wave plate 31, lead magnesium niobate (PMN-PT) 32, and a reflecting mirror 33. The grating 23 is located at the focal plane of the second cylindrical lens 21 and the PMN-PT 32 is located at the focal plane of the fifth cylindrical lens 25.
The PMN-PT has stable physical and chemical properties, is easy to process, low in cost and excellent in electro-optic effect. The PMN-PT material is isotropic under the action of no external electric field. The PMN-PT material is expressed as uniaxial crystals under the action of an externally applied electric field. When the optical axis direction of the PMN-PT is the light-passing surface direction, the side surface of the PMN-PT is pressurized, and the PMN-PT is equivalent to a wave plate. By applying the magnitude of the voltage, the phase retardation differences in different polarization directions can be controlled. When the optical axis direction of the PMN-PT is the light-passing surface direction, the pressure is applied in the light-passing surface direction, and the refractive index of the PMN-PT changes, which is equivalent to a phase retarder. The difference in phase delay between the front and rear passes can be controlled by the magnitude of the applied voltage.
The structure of the first embodiment of the present invention is shown in fig. 2, in which a cylindrical mirror is used to compress the device size, and the grating may be a prism grating, a blazed grating, a normal grating, etc., and in this example, a prism grating is used as an example. The optical front end shapes and expands the light spot at the output end of the optical fiber into an elliptical light spot, and the input random polarized light is changed into two linearly polarized light beams with the same polarization state and a certain included angle by using the Wollaston prism and the half-wave plate. The grating spreads the input light in terms of wavelength diffraction. To reduce cost, the traditional LCOS optical engine is replaced with a PMN-PT optical engine. Inside the optical engine, linearly polarized light is first rotated by 45 ° polarization angle through a half-wave plate, and different wavelengths strike different units of the side-powered PMN-PT. The PMN-PT side voltages of different units are controlled, so that the polarization angles of different channels of light can be changed, and the light returns through the original path of the reflecting mirror. The Wollaston prism in the optical front end only allows light with specific polarization state to return to the output port, and the proportion of the polarization state in the reflected light directly corresponds to the power of the light returned to the output port, so that the balance of the power of different channels is realized.
The principle of a second embodiment of the invention is shown in fig. 3, which consists of optical front ends 1, 4fSystem 2, optical engine 3. The optical front end 1 is composed of an input/output optical fiber array 11, a micro lens array 12, a first cylindrical lens 13, a Wollaston prism 14 and a half-wave plate 15. 4fThe system 2 is composed of a second cylindrical lens 21, a third cylindrical lens 22, a grating 23, a fourth cylindrical lens 24, and a fifth cylindrical lens 25. The fourth cylindrical lens 24 is a mirror image of the third cylindrical lens 22 with respect to the grating, and the fifth cylindrical lens 25 is a mirror image of the second cylindrical lens 21 with respect to the grating. The optical engine 3 is composed of a half-wave plate 31, lead magnesium niobate (PMN-PT) 32, a reflecting mirror 33, a polarization splitting prism 34, and a compensation block 35. The grating 23 is located at the focal plane of the second cylindrical lens 21 and the PMN-PT 32 is located at the focal plane of the fifth cylindrical lens 25. The optical front end portion of the second embodiment of the present invention is identical to that of the first embodiment, and only the optical engine is different. The structure of the second embodiment of the present invention is shown in fig. 4, where the light input to the PMN-PT optical engine is in the same polarization state, and is rotated by 45 ° by the half-wave plate, and is split into two beams of light with perpendicular polarization states by the polarization splitting prism, one beam of light is incident on the reflecting mirror after passing through the reflection and compensation block, and the other beam of light is continuously propagated and incident on the PMN-PT pressurized by the light passing surface. The total optical path of the incident PMN-PT can be changed by controlling the voltages of different units on the PMN-PT pressurized by the light-passing surface. The backward light after PMN-PT phase delay is converged with the reflected backward light and is combined by the polarization beam splitter prism, and the polarization state of the backward light after being combined is changed due to the phase delay of one beam of light. The wollaston prism in the optical front end allows only light of a specific polarization state to returnThe proportion of the polarization state in the reflected light directly corresponds to the magnitude of the optical power returned to the output port, so that the balance of the optical power of different channels is realized.
The invention provides two dynamic channel equalization filter structures based on electro-optic ceramic materials, which are divided into a first embodiment of the invention and a second embodiment of the invention. The two schemes differ only in the optical engine.
The principle of the first embodiment of the invention is shown in fig. 1, and the first embodiment of the invention consists of an input/output optical fiber array, a micro lens array, three cylindrical lenses, a Wollaston prism, two half wave plates, a grating, PMN-PT and a reflecting mirror. The input/output optical fiber array 11, the micro lens array 12, the first cylindrical lens 13, the Wollaston prism 14 and the half-wave plate 15 form the optical front end 1. The second cylindrical lens 21, the third cylindrical lens 22, the grating 23, the fourth cylindrical lens 24 and the fifth cylindrical lens 25 form 4fSystem 2. The fourth cylindrical lens 24 is a mirror image of the third cylindrical lens 22 with respect to the grating, and the fifth cylindrical lens 25 is a mirror image of the second cylindrical lens 21 with respect to the grating. The half-wave plate 31, PMN-PT 32 and mirror 33 constitute the optical engine 3. The grating 23 is located at the focal plane of the second cylindrical lens 21 and the PMN-PT 32 is located at the focal plane of the fifth cylindrical lens 25. A DWDM (dense wavelength division multiplexing) optical signal with random polarization is input from a pigtail of the input/output optical fiber array 11, and is changed from a circular light spot to an elliptical light spot after beam expansion and shaping by the microlens array 12 and the first cylindrical lens 13. After passing through the Wollaston prism 14, two beams of linearly polarized light (observed in a top view) with a certain included angle and with a mutually perpendicular polarization state are formed, wherein one beam of light changes the deflection polarization direction through the half-wave plate 15, and finally two beams of linearly polarized light with the same polarization state (P light, namely parallel to the top view) are obtained, after passing through the grating 23, the light with different wavelengths is dispersed and unfolded (observed in the top view), after passing through the third cylindrical lens 22 and the mirror image fourth cylindrical lens 24 thereof, a certain included angle (observed in the side view) is formed, after passing through the half-wave plate 31, the light is focused on the PMN-PT 32, after being reflected by the reflecting mirror 33, the light passes through the PMN-PT 32, the half-wave plate 31, the fifth cylindrical lens 25, the fourth cylindrical lens 24, the grating 23, the third cylindrical lens 22 and the second cylindrical lens 21 in sequence, after passing through the half-wave plate 15 and the Wollaston prism 14, the two beams have a clampThe angular linearly polarized light is recombined into a bundle of randomly polarized light (viewed in a plan view), and then passes through the first cylindrical lens 13 and the microlens array 12 and returns to the pigtail of the input-output optical fiber array 11. The side of the PMN-PT 32 (in the direction of the top view) is equivalent to a wave plate after a voltage is applied, and different voltages correspond to different deflection angles. By controlling the voltage, the proportion of light of different polarization in the reverse light can be changed. Only the reverse light energy of a specific polarization state passes through the wollaston prism 14, and the light of different polarization states cannot return to the tail fiber of the input/output optical fiber array 11. Light with different wavelengths is dispersed and spread on different positions of the PMN-PT 32 (observed in a top view) through the grating 23, and different attenuation can be applied to different channels by changing voltages of different positions of the PMN-PT 32, so that dynamic gain balance of different channels is realized.
The wollaston prism 14 of the optical front end 1 and the half wave plate 15 act as polarization diversity and limit that only the P light energy in the reverse light returns to the pigtail of the input-output optical fiber array 11. As shown in fig. 5 (a), the input light I1 is in a random polarization state, and is split into two light beams, I2 and I3, after passing through the wollaston prism. The S light I3 is changed into P light I4 after passing through the half wave plate 14, and finally two P light beams with a certain included angle are obtained. As shown in fig. 5 (b), when the polarization state of the reflected light is P light, that is, when no polarization state change occurs, the reflected light O2 is changed into S light O3 after passing through the half-wave plate 14, the P light O1 and the S light O3 have the same polarization state as I2 and I3 at the time of input, and the light O4 combined into a bundle of light with random polarization state after passing through the wollaston prism 14 is returned to the pigtail of the input/output optical fiber array 11. As shown in fig. 5 (c), when the polarization state of the reflected light is S light, that is, the polarization direction of the reflected light is deflected by 90 °, the reflected light O6 is changed into P light O7 after passing through the half-wave plate 15, and the S light O5 and the P light O7 are opposite to the I2 and I3 polarization states at the time of input, and pass through the wollaston prism 15 to diverge along the O7 and O8 directions, so that the reflected light cannot return to the pigtails of the input/output optical fiber array 11.
The polarization state of light inside the optical engine 3 of the first embodiment of the present invention is changed as shown in fig. 6, and the optical axis direction of the half-wave plate 31 is 22.5 ° to the P-ray direction as shown in (a) of fig. 6. As shown in FIG. 6 (b), the input light polarization state is shown as P1The polarization state of the P light passing through the half-wave plate 31 is shown as P2, and forms an angle of 45 ° with the P light direction. The optical axis direction of the PMN-PT 32 after side pressurization is consistent with the P light direction. When no voltage is applied to the side face of the PMN-PT 32, that is, no phase delay difference exists, the polarization state of the light reflected by the PMN-PT 32 and the reflecting mirror 33 is unchanged as shown by P3, and the output polarization state is consistent with the input polarization state after passing through the half-wave plate 31, as shown by P4. Let the applied voltage be V when the phase delay difference of PMN-PT 32 is equal to pi/2 π/2 . As shown in FIG. 6 (c), when the voltage applied to the side of the PMN-PT 32 is 0~V π/2 In other words, the phase retardation difference generated by the reciprocation passing through the PMN-PT 32 is 0 to pi, the polarization direction of the reflected light is elliptically polarized light as shown by P7, and the polarization direction of the output light after passing through the half wave plate 31 again is elliptically polarized light as shown by P8. As shown in FIG. 6 (d), when the voltage applied to the side of the PMN-PT 32 is V π/2 When the light passes through the half-wave plate 31, the polarization state of the output light is shown as P12, and the polarization state of the reflected light is shown as P11, and is vertical to the polarization state P10 of the input light.
The P light input to the optical engine 3 can be converted into S light or elliptically polarized light by controlling the voltage applied to the PMN-PT 32. When the applied voltage is V, the phase delay difference to and from the PMN-PT 32 is:
let the light vector input to the optical engine 3 beEP-ray direction light vector after passing through half-wave plate 31E 1 S-ray direction light vectorE 2 The method comprises the following steps:
after passing back and forth the PMN-PT 32 again, the P light direction light vectorE 3 The method comprises the following steps:
after passing back and forth the PMN-PT 32 again, the S-ray direction light vectorE 4 The method comprises the following steps:
after reflection, the light passes through the half wave plate 31 again, and the light vector in the P directionE 5 The method comprises the following steps:
after reflection, the light passes through the half wave plate 31 again, and the S light is directed to the light vectorE 6 The method comprises the following steps:
since only P light in the reflected light returns to the pigtail of the input/output optical fiber array 11, the ratio of the finally obtained optical power to the input power is:
the optical power attenuation and V/V are shown in FIG. 8 π/2 As the voltage increases, the optical power decays more and more.
The principle of the second embodiment of the invention is shown in fig. 2, and the second embodiment of the invention consists of an input/output optical fiber array, a micro lens array, three cylindrical lenses, a Wollaston prism, two half wave plates, a grating, a polarization beam splitter prism, a compensation block, a PMN-PT and a reflecting mirror. The half wave plate 31, the PMN-PT 32, the reflecting mirror 33, the polarization splitting prism 34, and the compensation block 35 constitute the optical engine 3.PMN-PT 32 is equivalent to a phase retarder after a voltage is applied to the front side (light propagation direction), different voltages corresponding to different phase retardations. The incident light is split into two light beams with different polarization states (viewed in side view) after passing through the polarization splitting prism 34, one light beam continuously propagates straight and is incident on the PMN-PT 32, and the other light beam is reflected twice and is incident on the reflecting mirror 33 after passing through the compensating block 35. The reverse light after the phase delay of PMN-PT 32 and the reverse light reflected by the reflecting mirror 33 are combined by the polarization splitting prism 14. Because one of the beams of light is subjected to phase delay, the polarization state of the combined reverse light can be changed. Only the reverse light energy with a specific polarization state is returned to the tail fiber of the input/output optical fiber array 11 through the Wollaston prism 32. Light with different wavelengths is dispersed and spread on different positions of the PMN-PT 32 (observed in a top view) through the grating 23, and different attenuation can be applied to the light with different wavelengths by changing voltages of different positions of the PMN-PT 32, so that dynamic gain balance of different wavelengths is realized.
The polarization state change of the light inside the optical engine 3 according to the second embodiment of the present invention is shown in fig. 7. The crystal axis direction of the half wave plate 31 is at an angle of 22.5 ° to the P-ray direction as shown in fig. 7 (a). As shown in fig. 7 (b), the polarization state of the input light is P light as shown by P13, and the polarization state of the light passing through the half-wave plate 31 is P14, which forms an angle of 45 ° with the direction of the P light. After passing through the polarization splitting prism 34, the light is split into two beams, one beam is P light P15, which continuously propagates linearly and is incident on the PMN-PT 32, and the other beam is S light P16, which is reflected twice and is incident on the reflecting mirror 33 through the compensating block 35. When no voltage is applied to the light passing surface of the PMN-PT 32, i.e. no phase delay exists, no phase difference exists between the reflected light and the input light, the reflected light passes through the polarization splitting prism 34, is shown as P17, passes through the half wave plate 31 and is P light P18, and the reflected light is consistent with the input polarization state P13. When the PMN-PT 32 light-passing surface is electrified and the optical axis direction is the light-passing surface direction, the refractive index of the PMN-PT 32 is changed, and when the equivalent optical cavity length change amount of the PMN-PT 32 is equal to 1/4 wavelength, the electrified voltage is V 1 . As shown in FIG. 7 (c), when the applied voltage is 0~V 1 The phase difference of the reflected light is 0-pi, the reflected light is changed into elliptical polarized light as shown by P23 after being combined by a polarization beam splitter prism 34, and the elliptical polarized light P24 is formed after the reflected light passes through a half wave plate 31, and the reflected light comprises P light and S light components. As shown in FIG. 7 (d), when the voltage applied to the light-passing surface of the PMN-PT 32 is V 1 I.e. the phase difference of the reflected light is pi, and the light is changed into polarized light after being combined by the polarization beam splitter prism 34, as shown by P29, and is vertical to the polarization state P26 of the input light, and then passes through half waveThe sheet 31 is followed by S-ray P30.
The P light input to the optical engine 3 can be converted into S light or elliptically polarized light by controlling the voltage applied to the PMN-PT 32. When the applied voltage is V, the phase difference between the light passing back and forth through the PMN-PT 32 and the light reflected back through the compensation plate is:
let the light vector input to the optical engine 45 beE' P-ray light vector after beam splitting by half-wave plate 31 and polarization beam splitter prism 34E 1 ' S light vectorE 2 ' is:
s light is reflected by the compensating block 35 and the reflecting mirror 33 to form a light vectorE 3 ' is:
p light back and forth through PMN-PT 22 back direction light vectorE 4 ' is:
the light vector of the two beams of light after being combined by the polarization beam splitter prism 40 isE 3 ' sumE 4 ' superposition, after passing through half-wave plate 31, the light vector of the light P direction is outputE 5 ' is:
after passing through the half wave plate 31, the output light S-beam direction light vectorE 6 ' is:
since only P light in the reflected light returns to the pigtail of the input/output optical fiber array 11, the ratio of the finally obtained optical power to the input power is:
the optical power attenuation and V/V are shown in FIG. 9 1 As the voltage increases, the optical power decays more and more.
It will be readily appreciated by those skilled in the art that the foregoing description is merely a preferred embodiment of the invention and is not intended to limit the invention, but any modifications, equivalents, improvements or alternatives falling within the spirit and principles of the invention are intended to be included within the scope of the invention.
Claims (10)
1. A dynamic channel equalization filter, comprising: optical front ends (1, 4)fA system (2) and an optical engine (3);
the optical front end (1) is used for shaping and expanding light spots at the output end of the optical fiber into elliptical light spots and converting input random polarized light into two linearly polarized light beams with certain included angles and the same polarization state;
said 4fThe system (2) is used for controlling the size of the light plate of the image plane to be consistent with the object plane, and spreading light according to wavelength dispersion through the grating of the focal plane;
the optical engine (3) adopts the mode that the polarization angle of different channels of light is changed by powering on the side face of the electro-optical ceramic, or the total optical path is changed by pressurizing the light passing face of the electro-optical ceramic so as to realize dynamic gain compensation on unbalanced channel power.
2. Dynamic channel equalization filter according to claim 1, characterized in that the optical engine (3) comprises a half-wave plate (31), an electro-optic ceramic (32) and a mirror (33);
the half-wave plate (31) is used for rotating the linearly polarized light by 45 degrees in polarization angle, and making different wavelengths incident to different units of the electro-optic ceramic (32) with the side surface powered on, so that the side surface voltages of the electro-optic ceramic (32) of the different units are controlled, the polarization angle of different channels of light can be changed, and the light returns through the original path of the reflecting mirror (33).
3. Dynamic channel equalization filter according to claim 1, characterized in that the optical engine (3) comprises a half-wave plate (31), a polarization splitting prism (34), an electro-optical ceramic (32), a compensation block (35) and a mirror (33);
the linearly polarized light is rotated by 45 degrees through a half wave plate (31), is divided into two beams of light with perpendicular polarization states through a polarization beam splitter prism (34), one beam of light is incident on a reflecting mirror (33) after passing through a reflection and compensation block (35), and the other beam of light is continuously transmitted and incident on an electro-optic ceramic (32) pressurized by a light passing surface.
4. A dynamic channel equalization filter as claimed in claim 3, characterized in that the total optical path length incident on the electro-optic ceramic (32) is changed by controlling the voltages of the different cells on the electro-optic ceramic (32) pressurized by the light passing surface; the backward light after the phase delay of the electro-optical ceramic (32) is converged with the reflected backward light and is combined by the polarization splitting prism, and the polarization state of the backward light after the combination is changed due to the phase delay of one beam of light.
5. Dynamic channel equalization filter according to any of the claims 1-4, characterized in that the optical front-end (1) comprises: the optical fiber array comprises an input/output optical fiber array (11), a micro lens array (12), a first cylindrical lens (13), a Wollaston prism (14) and a half-wave plate (15);
the input/output optical fiber array (11) is used for fixing the angle and the position of input light;
the microlens array (12) is used for expanding input light;
the first cylindrical lens (13) is used for shaping a circular light spot into an elliptical light spot;
the Wollaston prism (14) is used for dividing input light into two light beams with different polarization states and only allowing light with a specific polarization state to return to an output port, and the proportion of the polarization state in reflected light directly corresponds to the power of the light returned to the output port, so that the balance of the power of different channels is realized;
the half-wave plate (15) is used for changing the polarization state of light.
6. The dynamic channel equalization filter of any of claims 1-4, wherein the 4fThe system (2) comprises a second cylindrical lens (21), a third cylindrical lens (22), a grating (23), a fourth cylindrical lens (24) and a fifth cylindrical lens (25);
the second lens (21) is used for forming 4fThe system realizes the control of the image plane light spots;
the third cylindrical lens (22) is used for deflecting light beams to realize convergence and port switching;
the grating (23) is used for expanding input light according to wavelength diffraction;
the fourth cylindrical lens (24) is used for deflecting light beams to realize convergence and port switching;
the fifth cylindrical lens (25) is used for forming 4fThe system realizes the control of the focal spot on the image plane.
7. A dynamic channel equalization filter as claimed in claim 2 or 3, characterized in that said electro-optic ceramic (32) is a lead magnesium niobate, lithium niobate or KDP crystal.
8. The dynamic channel equalization filter of claim 7, wherein when the direction of the optical axis of the lead magnesium niobate is the direction of the light passing surface, the lead magnesium niobate is pressurized at the side thereof, and is equivalent to a wave plate; the phase retardation differences in different polarization directions can be controlled by the magnitude of the applied voltage.
9. The dynamic channel equalization filter of claim 7, wherein when the direction of the optical axis of the lead magnesium niobate is the direction of the light passing surface, the lead magnesium niobate is pressurized in the direction of the light passing surface, and the refractive index of the lead magnesium niobate is changed, which is equivalent to a phase retarder; the difference in phase delay between the front and rear passes can be controlled by the magnitude of the applied voltage.
10. A fiber optic communication system comprising the dynamic channel equalization filter of any of claims 1-9.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311296638.XA CN117031794B (en) | 2023-10-09 | 2023-10-09 | Dynamic channel equalization filter and optical fiber communication system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311296638.XA CN117031794B (en) | 2023-10-09 | 2023-10-09 | Dynamic channel equalization filter and optical fiber communication system |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN117031794A CN117031794A (en) | 2023-11-10 |
| CN117031794B true CN117031794B (en) | 2023-12-26 |
Family
ID=88630445
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202311296638.XA Active CN117031794B (en) | 2023-10-09 | 2023-10-09 | Dynamic channel equalization filter and optical fiber communication system |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN117031794B (en) |
Citations (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS57150209A (en) * | 1981-03-11 | 1982-09-17 | Mitsubishi Electric Corp | Automatic gain controlling circuit of optical signal |
| WO2003013033A1 (en) * | 2001-07-27 | 2003-02-13 | Thales | Electro-optical device for channel equalization in a multichannel optical link |
| JP2003348022A (en) * | 2002-05-29 | 2003-12-05 | Toshiba Corp | Optical transmitter |
| CN1529425A (en) * | 2003-09-29 | 2004-09-15 | 武汉光迅科技有限责任公司 | Adjustable luminous power divider |
| CN1624508A (en) * | 2004-11-26 | 2005-06-08 | 中国科学院上海光学精密机械研究所 | Direfraction filter spectrum gain equalizer and its manufacturing method |
| CN201051188Y (en) * | 2007-07-04 | 2008-04-23 | 福州高意通讯有限公司 | An optical modulator |
| CN101706615A (en) * | 2009-11-30 | 2010-05-12 | 浙江大学 | Electro-optical crystal based quick polarization control method |
| CN202948221U (en) * | 2012-11-25 | 2013-05-22 | 华中科技大学 | High-speed shutter device |
| DE102016107068A1 (en) * | 2016-04-15 | 2017-10-19 | Dausinger & Giesen Gmbh | Phase synchronized modulatable resonant electro-optic modulator for switching high power laser pulses |
| CN109103738A (en) * | 2018-08-03 | 2018-12-28 | 华中科技大学 | A kind of solid state laser of full pumping zero heat of range |
| CN111711052A (en) * | 2020-06-04 | 2020-09-25 | 中国科学院上海光学精密机械研究所 | Chirped pulse spectrum shaping device and method based on electro-optic modulation |
| CN112887029A (en) * | 2019-11-29 | 2021-06-01 | 华为技术有限公司 | Optical amplifier, optical signal processing method, and storage medium |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6681073B2 (en) * | 2001-03-19 | 2004-01-20 | Molecular Optoelectronics Corporation | Fiber optic power control systems and methods |
| US10243653B2 (en) * | 2016-05-27 | 2019-03-26 | Schafer Aerospace, Inc. | System and method for high speed satellite-based free-space laser communications using automatic gain control |
-
2023
- 2023-10-09 CN CN202311296638.XA patent/CN117031794B/en active Active
Patent Citations (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS57150209A (en) * | 1981-03-11 | 1982-09-17 | Mitsubishi Electric Corp | Automatic gain controlling circuit of optical signal |
| WO2003013033A1 (en) * | 2001-07-27 | 2003-02-13 | Thales | Electro-optical device for channel equalization in a multichannel optical link |
| JP2003348022A (en) * | 2002-05-29 | 2003-12-05 | Toshiba Corp | Optical transmitter |
| CN1529425A (en) * | 2003-09-29 | 2004-09-15 | 武汉光迅科技有限责任公司 | Adjustable luminous power divider |
| CN1624508A (en) * | 2004-11-26 | 2005-06-08 | 中国科学院上海光学精密机械研究所 | Direfraction filter spectrum gain equalizer and its manufacturing method |
| CN201051188Y (en) * | 2007-07-04 | 2008-04-23 | 福州高意通讯有限公司 | An optical modulator |
| CN101706615A (en) * | 2009-11-30 | 2010-05-12 | 浙江大学 | Electro-optical crystal based quick polarization control method |
| CN202948221U (en) * | 2012-11-25 | 2013-05-22 | 华中科技大学 | High-speed shutter device |
| DE102016107068A1 (en) * | 2016-04-15 | 2017-10-19 | Dausinger & Giesen Gmbh | Phase synchronized modulatable resonant electro-optic modulator for switching high power laser pulses |
| CN109103738A (en) * | 2018-08-03 | 2018-12-28 | 华中科技大学 | A kind of solid state laser of full pumping zero heat of range |
| CN112887029A (en) * | 2019-11-29 | 2021-06-01 | 华为技术有限公司 | Optical amplifier, optical signal processing method, and storage medium |
| CN111711052A (en) * | 2020-06-04 | 2020-09-25 | 中国科学院上海光学精密机械研究所 | Chirped pulse spectrum shaping device and method based on electro-optic modulation |
Non-Patent Citations (8)
| Title |
|---|
| La-doped PMN-PT transparent ceramics with ultra-high electro-optic effect and its application in optical devices;Hu, M 等;《JOURNAL OF ADVANCED CERAMICS》;第12卷(第7期);第1441-1453页 * |
| MEMS-based tunable flat-top narrow-band optical filter;米仁杰 等;《红外与激光工程》;第45卷(第7期);第0720001页 * |
| MEMS可调谐平顶窄带光学滤波器;米仁杰，万助军，汪涵;《红外与激光工程》;第45卷(第7期);第143-147页 * |
| New optical phenomena in ferroelectrics: Applications for the recording and processing of information;O.G. Vlokh;《IEEE》;第57卷(第5期);第653页 * |
| Ultrashort polarization-tailored bichromatic fields;Kerbstadt, S 等;《JOURNAL OF MODERN OPTICS》;第64卷(第10-11期);第1010-1025页 * |
| Wang, Y. ; Ge, K. ; Wan, Z..A variable gain tilting filter for dynamic gain flattening of erbium-doped fiber amplifiers.《 2022 International Conference on Optoelectronic Information and Functional Materials (OIFM 2022)》.2022,第12255卷第1225508页. * |
| 基于多波长光纤激光器的微波光子滤波器研究;付小璞;《中国优秀硕士学位论文全文数据库（电子期刊）》(第12期);第I135-22页 * |
| 多信道动态色散补偿器的研究进展;尤全 等;《光通信研究》(第4期);第19-22页 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN117031794A (en) | 2023-11-10 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US5740288A (en) | Variable polarization beam splitter, combiner and mixer | |
| US6285500B1 (en) | Wavelength selective switch | |
| CA1241560A (en) | Optical multiplexer and demultiplexer | |
| US6859573B2 (en) | Double pass arrangement for a liquid crystal device | |
| US6801310B2 (en) | Liquid crystal modulator and polarization diversity optics for optical communications | |
| US6529307B1 (en) | Selective intensity modulation of channels in a multiplexed optical communication system | |
| CN104460020B (en) | Beam treatment device, beam attenuation switching device and optical wavelength selecting switch system | |
| Riza et al. | Reconfigurable wavelength add-drop filtering based on a Banyan network topology and ferroelectric liquid crystal fiber-optic switches | |
| US20030021526A1 (en) | Dynamic dispersion compensator | |
| CN103353633B (en) | Wavelength-selective switches and Wavelength selecting method | |
| JPS62105116A (en) | Double refraction optical multiplexer having flattened band | |
| CN102590952B (en) | Multi-channel dynamic optical dispersion compensator | |
| US8873898B2 (en) | Polarization independent wavelength converter and polarization independent wavelength conversion method | |
| US20020126935A1 (en) | Tunable periodic filter | |
| US6441960B1 (en) | Optical interleavers with minimized dispersion | |
| US20010048556A1 (en) | Wavelength selective switch | |
| CN117031794B (en) | Dynamic channel equalization filter and optical fiber communication system | |
| US20020122251A1 (en) | Wavelength selective switch and variable optical attenuator | |
| CN103336324A (en) | Interferential comb filter | |
| CN103091787B (en) | Adjustable optical attenuator and adjustable optical attenuator wavelength division multiplexer | |
| CN105182473B (en) | A kind of wavelength selective optical disabler | |
| Yun et al. | A 1× 2 variable optical power splitter development | |
| CN104155723A (en) | Optical switching module based on wedge-shaped liquid crystal box | |
| CN1266502C (en) | Antipolarization correlation loss light beam exchange | |
| Li et al. | Interleaver technology review |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |