CN114253009A - Light polarization state infinite polarization tracking system and method - Google Patents
Light polarization state infinite polarization tracking system and method Download PDFInfo
- Publication number
- CN114253009A CN114253009A CN202111340030.3A CN202111340030A CN114253009A CN 114253009 A CN114253009 A CN 114253009A CN 202111340030 A CN202111340030 A CN 202111340030A CN 114253009 A CN114253009 A CN 114253009A
- Authority
- CN
- China
- Prior art keywords
- light
- signal
- polarization state
- phase modulator
- polarization
- 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.)
- Pending
Links
- 230000010287 polarization Effects 0.000 title claims abstract description 111
- 238000000034 method Methods 0.000 title claims abstract description 36
- 230000003287 optical effect Effects 0.000 claims abstract description 58
- 238000000605 extraction Methods 0.000 claims abstract description 14
- 230000008569 process Effects 0.000 claims abstract description 14
- 239000000284 extract Substances 0.000 claims abstract description 9
- 239000011159 matrix material Substances 0.000 claims description 6
- 230000006854 communication Effects 0.000 abstract description 10
- 238000004891 communication Methods 0.000 abstract description 9
- 230000001427 coherent effect Effects 0.000 description 12
- 238000010586 diagram Methods 0.000 description 5
- 238000004590 computer program Methods 0.000 description 3
- 238000001514 detection method Methods 0.000 description 3
- 230000004048 modification Effects 0.000 description 3
- 238000012986 modification Methods 0.000 description 3
- 230000010355 oscillation Effects 0.000 description 3
- 230000008859 change Effects 0.000 description 2
- 239000013307 optical fiber Substances 0.000 description 2
- 230000035945 sensitivity Effects 0.000 description 2
- 230000006641 stabilisation Effects 0.000 description 2
- 238000011105 stabilization Methods 0.000 description 2
- 230000004075 alteration Effects 0.000 description 1
- 230000035559 beat frequency Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 230000008878 coupling Effects 0.000 description 1
- 238000010168 coupling process Methods 0.000 description 1
- 238000005859 coupling reaction Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
Images
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
- G02F1/0136—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 for the control of polarisation, e.g. state of polarisation [SOP] control, polarisation scrambling, TE-TM mode conversion or separation
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
- G02B27/28—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00 for polarising
- G02B27/283—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00 for polarising used for beam splitting or combining
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
- G02B27/28—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00 for polarising
- G02B27/286—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00 for polarising for controlling or changing the state of polarisation, e.g. transforming one polarisation state into another
-
- 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
- G02F1/0121—Operation of devices; Circuit arrangements, not otherwise provided for in this subclass
Landscapes
- Physics & Mathematics (AREA)
- Nonlinear Science (AREA)
- General Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Optical Modulation, Optical Deflection, Nonlinear Optics, Optical Demodulation, Optical Logic Elements (AREA)
Abstract
The invention belongs to the technical field of optical communication, and particularly relates to an infinite polarization tracking system and method of a light polarization state, wherein the method comprises the following steps that a secondary phase modulator receives a beam of polarized light emitted by an optical transmitter and adjusts the polarization state of the polarized light to output signal light, and the signal light comprises first signal light and second signal light; the extraction module extracts X, Y polarization direction optical power of the signal light and converts the optical power into an electric signal; the processing module receives the electric signals and processes the electric signals to obtain X, Y difference of optical power in the polarization direction; the processing module processes the electric signal through a diter algorithm to obtain a Stokes vector of the current signal light and obtain a control voltage signal according to the Stokes vector; the second-stage phase modulator adjusts the polarization state of the polarized light according to the control voltage signal, so that the output signal light tends to a circular ring with S1 being 0 on the Poincare sphere. The invention can realize the stability of light polarization state through the secondary phase modulation structure.
Description
Technical Field
The invention belongs to the technical field of optical communication, and particularly relates to an infinite polarization tracking system and method for a light polarization state.
Background
Coherent optical communication systems have the advantages of high sensitivity, long relay distance, large communication capacity, multiple modulation modes, and the like, and are widely used. Coherent optical communication mainly utilizes coherent modulation and heterodyne detection technologies, wherein coherent modulation is to change the frequency, phase and amplitude of an optical carrier by using a transmitted signal, so that an optical signal is required to have a determined frequency and phase, and heterodyne detection is to perform coherent coupling on a receiving end by using a beam of local oscillator light and signal light in an optical coupler to obtain a beat frequency signal which changes according to the same rule as the frequency, phase and amplitude of the signal light. Coherent reception is sensitive to polarization of light, and therefore in a coherent optical communication system, it is required that the frequency and phase of a local oscillation optical signal and signal light are stable, and it is also required that the polarization states of the local oscillation optical signal and received optical signal are consistent. However, in the communication process, signal light is transmitted in the optical fiber, and the movement, vibration, temperature change, etc. of the optical fiber can cause the disturbance of the polarization state of the signal light, so that the polarization state of the optical signal needs to be tracked, stabilized and controlled in real time.
The existing SHCD (self-homodyne coherent detection system) mainly transmits a modulated signal and a tone copy serving as a local oscillator signal from a transmitter to a receiver for coherent reception, can reduce the influence of local oscillator optical phase noise to the maximum extent, omits frequency offset, allows the use of an uncooled laser with a large line width, and simplifies a digital signal processing algorithm, but as with a conventional coherent optical communication system, the SHCD also has the problem of sensitivity to polarization during coherent reception. Therefore, a corresponding automatic polarization tracking scheme needs to be designed to compensate the polarization random variation of the received local oscillation signal.
Therefore, chinese patent CN112485930A discloses a control method and system for realizing polarization stability, which quickly adjusts the polarization state of output light after passing through a polarization controller by using a quick positioning algorithm to be near any specified target polarization state on the poincare sphere, and then further stabilizes the polarization state of the output light to be the target polarization state by using a random gradient descent algorithm, so as to realize the stabilization of any polarization state to any set target polarization state; however, the polarization controller formed by the five-stage equivalent phase difference adjustable angle fixed wave plate is required to adjust, when the voltage applied to the current three-stage wave plate reaches the limit, the voltage of the previous three-stage wave plate needs to be returned to the intermediate voltage so as to continuously adjust the voltage, the scheme is too complex, infinite tracking of the light polarization state cannot be achieved, the adjustment control speed is inevitably influenced, and the control effect is poor.
Disclosure of Invention
The present invention overcomes at least one of the above-mentioned drawbacks of the prior art and provides an infinite polarization tracking system and method for optical polarization state, which can realize infinite tracking control of optical polarization state through a secondary phase modulator.
In order to solve the technical problems, the invention adopts the technical scheme that:
there is provided a method of infinite polarization tracking of the polarization state of light, comprising the steps of:
step 1: the secondary phase modulator receives a beam of polarized light emitted from the optical transmitter and adjusts the polarization state of the polarized light to output signal light, wherein the signal light comprises first signal light and second signal light;
step 2: the extraction module extracts X, Y polarization direction optical power of the signal light and converts the optical power into an electric signal;
and step 3: the processing module receives the electric signals and processes the electric signals to obtain X, Y difference of optical power in the polarization direction;
and 4, step 4: the processing module processes the difference of the optical power through a diter algorithm to obtain a Stokes vector of the current signal light and obtain a control voltage signal according to the Stokes vector;
and 5: the second-stage phase modulator adjusts the polarization state of the polarized light according to the control voltage signal, so that the output signal light tends to a circular ring with S1 being 0 on the Poincare sphere.
In the scheme, the light power of the signal light X, Y in the polarization direction is directly extracted, the corresponding Stokes vector is calculated through a diter algorithm, the polarization state of the signal light is described by the Stokes vector, and the control voltage signal can be obtained through the Stokes vector, so that the polarization state of the polarized light can be adjusted by the secondary phase modulator according to the control voltage signal, and the polarization stability is realized.
Preferably, the step 2 specifically includes:
splitting the first signal light and the second signal light respectively through two power splitters to obtain a first light beam and a second light beam;
the two first light beams are respectively received by the two optical detectors and are converted into electric signals, and the second light beam is combined by the polarization beam combiner and then continuously transmitted on the original optical path.
Preferably, the processing the difference between the optical powers through a diter algorithm in the step 4 to obtain a stokes vector of the current signal light, and obtaining the control voltage according to the stokes vector specifically includes: extracting a Stokes S1 component of the current polarization state of the signal light;
estimating according to the Stokes S1 component by using a dither algorithm to obtain a Stokes S2 component;
and calculating a rotation angle from the rotation of the current polarization state around the S3 axis to S1 equal to 0 according to the Stokes S1 and S2 components, and obtaining a corresponding control voltage signal according to the rotation angle.
Preferably, the step 4 of estimating a stokes S2 component according to the stokes S1 component by using a diter algorithm specifically includes:
setting a perturbation matrix Vb, wherein Vb comprises Ld numerical values;
multiplying each numerical value in Vb by delta and then sequentially adding the numerical values to a second voltage control stage of the secondary phase modulator to respectively obtain feedback values delta S1 after perturbation; wherein, delta is the perturbation coefficient;
and calculating the value of the Stokes S2 component according to the feedback value delta S1, wherein the specific formula is as follows:
T1＝sum(ΔS1*Vb)/delta/Ld，
θ＝acos(min(1,-T1))，
wherein θ is ellipticity; delta S11、ΔS12、ΔS13、ΔS14Respectively obtaining feedback values by sequentially applying all the numerical values; t1 is obtained by perturbation of secondary phase modulatorAnd feeding back the value.
Preferably, in step 4, a perturbation matrix Va is simultaneously set, where Va contains Ld values, and when each value in Vb is multiplied by delta and then sequentially added to the second voltage control stage of the two-stage phase modulator, each value in Va is multiplied by delta and then sequentially added to the first voltage control stage of the two-stage phase modulator.
Preferably, the processing module inputs the inverted voltage to a second stage voltage control stage in the two-stage phase modulator when the rotation angle is 2 pi or 0.
The scheme also provides a system of the light polarization state infinite tracking method, which comprises an optical transmitter, a secondary phase modulator, an extraction module and a processing module which are connected in sequence, the optical transmitter transmits polarized light, the polarized light outputs signal light after being subjected to phase polarization state adjustment through the secondary phase modulator, the extraction module extracts partial power of the signal light and converts the partial power into an electric signal, the processing module processes the electric signal to obtain a control voltage signal, the control voltage signal is converted into the electric signal to be input into the secondary phase modulator, and the secondary phase modulator performs polarization state adjustment on the polarized light according to the control voltage signal, so that power values of the signal light in X, Y two polarization directions are equal.
Preferably, the two power optical splitters are respectively used for splitting the two paths of signal light output by the secondary phase modulator to obtain two first light beams and two second light beams, and the polarization beam combiner is used for combining the two second light beams.
Preferably, the extraction module includes two photodetectors, and the two photodetectors respectively receive the two first light beams and convert the two first light beams into electrical signals.
Preferably, the processing module comprises an FPGA, and an analog-to-digital converter and a digital-to-analog converter which are electrically connected with the FPGA;
the analog-to-digital converter is also electrically connected with the photoelectric detector, converts the electric signal output by the photoelectric detector into a digital signal and inputs the digital signal into the FPGA;
the FPGA processes the digital signal to obtain a control voltage signal;
the digital-to-analog converter is also electrically connected with the secondary phase modulation structure, converts the control voltage signal output by the FPGA into an electric signal and inputs the electric signal into the secondary phase modulator.
Compared with the prior art, the beneficial effects are:
the invention directly extracts the light power of X, Y polarization direction of the signal light, calculates the corresponding Stokes vector through the diter algorithm, describes the polarization state of the signal light by the Stokes vector, can obtain the control voltage signal through the Stokes vector, so that the secondary phase modulator can adjust the polarization state of the polarization light according to the control voltage signal, and realize the polarization stability; in addition, because the secondary phase modulator has a boundary, when the control reaches the boundary, the voltage direction is converted, so that the voltage of a first voltage control stage in the secondary phase modulator is rapidly converted, and the power of the signal light in the XY direction is not changed, so that the secondary phase modulator can realize infinite tracking control on the light polarization state.
Drawings
FIG. 1 is a schematic flow chart of an infinite tracking method for light polarization state according to example 1 of the present invention;
fig. 2 is a block diagram schematically illustrating a system of an infinite tracking method for light polarization state according to an embodiment 2 of the present invention.
Detailed Description
The drawings are for illustration purposes only and are not to be construed as limiting the invention; for the purpose of better illustrating the embodiments, certain features of the drawings may be omitted, enlarged or reduced, and do not represent the size of an actual product; it will be understood by those skilled in the art that certain well-known structures in the drawings and descriptions thereof may be omitted. The positional relationships depicted in the drawings are for illustrative purposes only and are not to be construed as limiting the invention.
The same or similar reference numerals in the drawings of the embodiments of the present invention correspond to the same or similar components; in the description of the present invention, it should be understood that if there are terms such as "upper", "lower", "left", "right", "long", "short", etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the drawings, it is only for convenience of description and simplicity of description, but does not indicate or imply that the device or element referred to must have a specific orientation, be constructed in a specific orientation, and be operated, and therefore, the terms describing the positional relationships in the drawings are only used for illustrative purposes and are not to be construed as limitations of the present patent, and specific meanings of the terms may be understood by those skilled in the art according to specific situations.
The technical scheme of the invention is further described in detail by the following specific embodiments in combination with the attached drawings:
example 1:
fig. 1 shows an embodiment of an optical polarization state infinite tracking method, which can be applied to a coherent optical communication system, and includes the following steps:
step 1: the secondary phase modulator receives a beam of polarized light emitted from the optical transmitter and adjusts the polarization state of the polarized light to output signal light, wherein the signal light comprises first signal light and second signal light;
step 2: the extraction module extracts X, Y polarization direction optical power of the signal light and converts the optical power into an electric signal;
and step 3: the processing module receives the electric signals and processes the electric signals to obtain X, Y difference of optical power in the polarization direction;
and 4, step 4: the processing module processes the difference of the optical power through a diter algorithm to obtain a Stokes vector of the current signal light and obtain a control voltage signal according to the Stokes vector;
and 5: the second-stage phase modulator adjusts the polarization state of the polarized light according to the control voltage signal, so that the output signal light tends to a circular ring with S1 being 0 on the Poincare sphere.
Step 2 in this embodiment specifically includes:
splitting the first signal light and the second signal light respectively through two power splitters to obtain a first light beam and a second light beam; it should be understood that the first signal light and the second signal light are obtained by splitting polarized light emitted by the same laser through the power splitter, so that the subsequent extraction of the light power in two different directions XY can be facilitated; in a specific embodiment, in order not to interfere with information transmission of the communication system, the power ratio of the first light beam to the second light beam is 10:90, and since the first light beam and the second light beam are identical except for the optical power, the whole polarized light can be controlled by only using the polarization state information of the first light beam for tracking;
the two first light beams are respectively received by the two optical detectors and are converted into electric signals, and the second light beam is combined by the polarization beam combiner and then continuously transmitted on the original optical path. After the optical signal of the first light beam is converted into the electric signal, the electric signal can be processed by accurate data.
In step 4 in this embodiment, processing the difference between the optical powers by a diter algorithm to obtain a stokes vector of the current signal light, and obtaining the control voltage according to the stokes vector specifically includes:
extracting a Stokes S1 component of the current polarization state of the signal light;
estimating according to the Stokes S1 component by using a dither algorithm to obtain a Stokes S2 component;
and calculating a rotation angle from the rotation of the current polarization state around the S3 axis to S1 equal to 0 according to the Stokes S1 and S2 components, and obtaining a corresponding control voltage signal according to the rotation angle.
In step 4 in this embodiment, estimating a stokes S2 component according to the stokes S1 component by using a diter algorithm specifically includes:
setting a perturbation matrix Vb, wherein Vb comprises Ld numerical values;
multiplying each numerical value in Vb by delta and then sequentially adding the numerical values to a second voltage control stage of the secondary phase modulator to respectively obtain feedback values delta S1 after perturbation; wherein, delta is a perturbation coefficient, and the size of the perturbation coefficient is adjustable;
and calculating the value of the Stokes S2 component according to the feedback value delta S1, wherein the specific formula is as follows:
T1＝sum(ΔS1*Vb)/delta/Ld，
θ＝acos(min(1,-T1))，
wherein θ isAn ellipticity; delta S11、ΔS12、ΔS13、ΔS14Respectively obtaining feedback values by sequentially applying all the numerical values; t1 is the feedback value obtained after the perturbation of the secondary phase modulator. The first voltage control stage and the second voltage control stage of the two-stage phase modulator in this embodiment are for converting the light polarization state by rotating the light polarization state by corresponding angles around the S1 and S3 axes in the stokes space, respectively, and the second voltage control stage rotates the light polarization state by a certain angle around the S3 axis and locks the light polarization state on a great circle with S1 being 0. Since the processing module can only extract the stokes S1 component of the current polarization state of the signal light, the specific rotation angle of the current polarization state distance S1-0 plane cannot be determined, and the specific rotation angle can only be determined by knowing the S1 component and the S2 component of the current polarization state at the same time for adjusting and controlling the light polarization state. Therefore, it is necessary to estimate the S2 component by the known S1 component, and the specific angle of the current polarization state rotating to the plane of S1 ═ 0 around the S3 axis can be determined by the S1 component and the S2 component, so as to obtain the control voltage of the second voltage control stage, so that the different polarization states are directly rotation-locked to the plane of S1 ═ 0 under the driving of the control voltage, and the stabilization of the polarization state of the light is realized.
In this embodiment, in step 4, perturbation matrix Va is simultaneously set, where Va includes Ld values, and when values in Vb are multiplied by delta and then sequentially added to the second voltage control stage of the secondary phase modulator, values in Va are multiplied by delta and then sequentially added to the first voltage control stage of the secondary phase modulator.
In order to realize infinite tracking control of the secondary phase modulator, in this embodiment, when the rotation angle is 2 pi or 0, the processing module inputs a reverse voltage to the second voltage control stage in the secondary phase modulator, and at this time, the first voltage control structure in the secondary phase modulator rotates around the S1 axis by an angle of pi or-pi, the voltage is rapidly changed, but the power in the polarization direction of X, Y is not obviously jittered or changed, the polarization state does not jump out of the current plane of S1 being 0, and infinite tracking control of the light polarization state is realized.
In this embodiment, the light power of the signal light X, Y in the polarization direction is directly extracted, a corresponding stokes vector is calculated through a diter algorithm, the polarization state of the signal light is described by the stokes vector, and a control voltage signal can be obtained through the stokes vector, so that the polarization state of the polarized light can be adjusted by the secondary phase modulator according to the control voltage signal, and polarization stability is realized; in addition, because the secondary phase modulator has a boundary, when the control reaches the boundary, the voltage of the first voltage control stage in the secondary phase modulator is changed sharply by changing the voltage direction, and the power of the signal light X, Y in the direction is not changed, so that the secondary phase modulator can realize infinite tracking control on the light polarization state.
Example 2:
fig. 2 shows an embodiment of a system of an infinite tracking method for a light polarization state, which is used to implement the infinite tracking method for a light polarization state in embodiment 1, and includes an optical transmitter, a secondary phase modulator, an extraction module, and a processing module, which are connected in sequence, where the optical transmitter transmits polarized light, the polarized light outputs signal light after being subjected to phase polarization state adjustment by the secondary phase modulator, the extraction module extracts partial power of the signal light and converts the signal light into an electrical signal, the processing module processes the electrical signal to obtain a control voltage signal, converts the control voltage signal into an electrical signal, and inputs the electrical signal into the secondary phase modulator, and the secondary phase modulator adjusts the polarization state of the polarized light according to the control voltage signal, so that power values of the signal light in X, Y two polarization directions are equal.
In this embodiment, the polarized light emitted from the optical transmitter is also split by a Polarization Beam Splitter (PBS), and the split light beams are all input to the secondary phase modulation structure for polarization state adjustment.
The two power optical splitters are respectively used for splitting the two paths of signal light output by the secondary phase modulator to obtain two first light beams and two second light beams, and the polarization beam combiner is used for combining the two second light beams. The signal light is split and then extracted by the optical detector, so that the original light path is not greatly influenced.
The extraction module in this embodiment includes two Photodetectors (PDs) that receive the two first light beams and convert them into electrical signals, respectively.
The processing module in the embodiment comprises an FPGA, and an analog-to-digital converter (AD) and a digital-to-analog converter (DA) which are electrically connected with the FPGA;
the analog-to-digital converter is also electrically connected with the photoelectric detector, converts the electric signal output by the photoelectric detector into a digital signal and inputs the digital signal into the FPGA;
the FPGA processes the digital signal to obtain control voltage signals (V1 and V2);
the digital-to-analog converter is also electrically connected with the secondary phase modulation structure, converts the control voltage signal output by the FPGA into an electric signal and inputs the electric signal into the secondary phase modulator.
The present invention has been described with reference to flowchart illustrations or block diagrams of methods, apparatus (systems) and computer program products according to embodiments of the application, and it is understood that each flow or block of the flowchart illustrations or block diagrams, and combinations of flows or blocks in the flowchart illustrations or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made to the above embodiments by those of ordinary skill in the art within the scope of the present invention.
It should be understood that the above-described embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention should be included in the protection scope of the claims of the present invention.
Claims (10)
1. A method for infinite tracking of the polarization state of light, comprising the steps of:
step 1: the two-stage phase modulator receives a beam of polarized light emitted by an optical transmitter and adjusts the polarization state of the polarized light to output signal light, wherein the signal light comprises first signal light and second signal light;
step 2: the extraction module extracts X, Y polarization direction optical power of the signal light and converts the optical power into an electric signal;
and step 3: the processing module receives the electric signals and processes the electric signals to obtain X, Y difference of optical power in the polarization direction;
and 4, step 4: the processing module processes the difference of the light powers through a diter algorithm to obtain a Stokes vector of the current signal light and obtain a control voltage signal according to the Stokes vector;
and 5: the second-stage phase modulator adjusts the polarization state of the polarized light according to the control voltage signal, so that the output signal light tends to a circular ring with S1 being 0 on the Poincare sphere.
2. A method for infinite tracking of the polarization state of light according to claim 1, wherein step 2 comprises:
splitting the first signal light and the second signal light respectively through two power splitters to obtain a first light beam and a second light beam;
the two first light beams are respectively received by the two optical detectors and are converted into electric signals, and the second light beam is combined by the polarization beam combiner and then continuously transmitted on the original optical path.
3. The method of claim 2, wherein the step 4 of processing the difference between the optical powers by a diter algorithm to obtain a stokes vector of the current signal light, and obtaining the control voltage according to the stokes vector specifically includes:
extracting a Stokes S1 component of the current polarization state of the signal light;
estimating a Stokes S2 component according to the Stokes S1 component by using a diter algorithm;
and calculating a rotation angle from the rotation of the current polarization state around the S3 axis to S1-0 according to the Stokes S1 and S2 components, and obtaining a corresponding control voltage signal according to the rotation angle.
4. The method for infinite tracking of a light polarization state according to claim 3, wherein the step 4 of estimating a stokes S2 component from the stokes S1 component by using a diter algorithm specifically comprises:
setting a perturbation matrix Vb, wherein Vb comprises Ld numerical values;
multiplying each numerical value in Vb by delta and then sequentially adding the numerical values to a second voltage control stage of the secondary phase modulator to respectively obtain feedback values delta S1 after perturbation; wherein, delta is the perturbation coefficient;
calculating the value of the Stokes S2 component according to the feedback value delta S1, wherein the specific formula is as follows:
T1＝sum(ΔS1*Vb)/delta/Ld，
θ＝acos(min(1,-T1))，
wherein θ is ellipticity; delta S11、ΔS12、ΔS13、ΔS14Respectively obtaining feedback values by sequentially applying all the numerical values; t1 is the feedback value obtained after the perturbation of the secondary phase modulator.
5. An optical polarization state infinite tracking method according to claim 4, wherein a perturbation matrix Va is simultaneously set in step 4, wherein Va contains Ld values, and when each value in Vb is multiplied by delta and then sequentially added to the second voltage control stage of the secondary phase modulator, each value in Va is multiplied by delta and then sequentially added to the first voltage control stage of the secondary phase modulator.
6. The method of claim 5, wherein the processing module inputs an inverted voltage to the second voltage control stage of the phase modulator when the rotation angle is 2 π or 0.
7. A system for implementing the method for infinitely tracking the polarization state of light according to any one of claims 1 to 6, comprising an optical transmitter, a secondary phase modulator, an extraction module and a processing module, which are connected in sequence, wherein the optical transmitter transmits polarized light, the polarized light outputs signal light after being subjected to phase polarization state adjustment by the secondary phase modulator, the extraction module extracts partial power of the signal light and converts the signal light into an electrical signal, the processing module processes the electrical signal to obtain a control voltage signal, converts the control voltage signal into an electrical signal and inputs the electrical signal into the secondary phase modulator, and the secondary phase modulator adjusts the polarization state of the polarized light according to the control voltage signal, so that the signal light tends to a circular ring with S1 ═ 0 on a poincare sphere.
8. The system according to claim 7, further comprising two power splitters and a polarization beam combiner, wherein the two power splitters are respectively configured to split the two signal beams output by the secondary phase modulator to obtain two first light beams and two second light beams, and the polarization beam combiner is configured to combine the two second light beams.
9. The system of claim 8, wherein the extraction module comprises two photodetectors, each receiving and converting two of the first light beams into an electrical signal.
10. The system of claim 7, wherein the processing module comprises an FPGA, and an analog-to-digital converter and a digital-to-analog converter both electrically connected to the FPGA;
the analog-to-digital converter is also electrically connected with the photoelectric detector, converts an electric signal output by the photoelectric detector into a digital signal and inputs the digital signal into the FPGA;
the FPGA processes the digital signal to obtain a control voltage signal;
the digital-to-analog converter is also electrically connected with the secondary phase modulation structure, converts the control voltage signal output by the FPGA into an electric signal and inputs the electric signal into the secondary phase modulator.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111340030.3A CN114253009A (en) | 2021-11-12 | 2021-11-12 | Light polarization state infinite polarization tracking system and method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111340030.3A CN114253009A (en) | 2021-11-12 | 2021-11-12 | Light polarization state infinite polarization tracking system and method |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN114253009A true CN114253009A (en) | 2022-03-29 |
Family
ID=80790804
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202111340030.3A Pending CN114253009A (en) | 2021-11-12 | 2021-11-12 | Light polarization state infinite polarization tracking system and method |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN114253009A (en) |
-
2021
- 2021-11-12 CN CN202111340030.3A patent/CN114253009A/en active Pending
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| EP2432139B1 (en) | Method, device and system for feedback control of a coherent receiver | |
| EP0578380B1 (en) | Fiber-optic transmission polarization-dependent distortion compensation | |
| US8200087B2 (en) | Method and device for stabilizing the state of polarization of a polarization multiplexed optical radiation | |
| US20120082464A1 (en) | Coherent optical receiving apparatus, coherent optical communications system employing same, and coherent optical communications method | |
| US20050265728A1 (en) | Optical communications based on optical polarization multiplexing and demultiplexing | |
| US20040208646A1 (en) | System and method for multi-level phase modulated communication | |
| CN105634591B (en) | Free space coherent light communication detection device based on 2 × 4 90 ° of optical bridging devices | |
| CN107346993A (en) | Optical signal coherence detection and device | |
| US7043122B2 (en) | PMD compensator based on separation of principal state of polarization control and differential group delay control, and method thereof | |
| CN117176259B (en) | Four-way multiplexing optical communication method and device based on self-coherence | |
| JP4015724B2 (en) | Method and apparatus for alignment control of two light waves during coherent superimposed reception | |
| US6859283B2 (en) | Apparatus and method for measuring phase response of optical detectors using multiple-beatnote optical heterodyne | |
| CN102185653B (en) | Based on the relevant radio telecommunicaltion system of frequency stabilized carbon dioxide laser, method and receiver | |
| CN114253009A (en) | Light polarization state infinite polarization tracking system and method | |
| CN109714068B (en) | Compact broadband channelized receiver based on optical processing technology | |
| Liu et al. | Study of multistage composite loop control based on optical phase-locked loop technology | |
| US5477369A (en) | Device for optical heterodyne or homodyne detection of an optical signal beam and receiver provided with such a device | |
| CN105721051B (en) | Free space coherent light communication detection device based on 2 × 2 180 ° of optical bridging devices | |
| CN113851920B (en) | Laser frequency difference control method and system | |
| EP0310174B1 (en) | Device for optical heterodyne or homodyne detection of an optical signal beam and receiver provided with such a device | |
| US4234971A (en) | Precise RF timing signal distribution to remote stations | |
| JPS60172842A (en) | Controller of optical reception circuit | |
| CN111682904A (en) | Device and method for stabilizing amplitude of radio frequency signal of coherent optical module modulation driver | |
| US5467414A (en) | Device for generating feedback signals to regulate optical monitoring circuits (PLL) | |
| CN214412738U (en) | Receiving end for quantum communication |
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 |