CN108599855B - Flexible and adjustable multi-level all-optical 2R regeneration device - Google Patents
Flexible and adjustable multi-level all-optical 2R regeneration device Download PDFInfo
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Abstract
The invention discloses a flexible and adjustable multi-level all-optical 2R regeneration device, wherein a deteriorated multi-level optical PAM signal to be regenerated is amplified in an optical amplifier and is adjusted to be consistent with the direction of a horizontal linear polarizer by a first polarization controller to obtain a horizontal polarization deteriorated multi-level optical PAM signal; adjusting the polarization direction of continuous auxiliary light emitted by the laser to be consistent with the polarization direction of the vertical linear polarizer through a second polarization controller to obtain vertical polarization auxiliary light; then, cross-phase modulation and interference coupling are carried out, and the vertical polarization auxiliary optical signal is modulated by the power of the degraded multi-level optical PAM signal, so that a power transfer function curve of the regenerated optical PAM signal power (namely, output power) with the step increase along with the increase of the power (namely, input power) of the degraded multi-level optical PAM signal is formed. It has the advantages of flexible and adjustable regeneration level, changeable regeneration working point and good consistency of regeneration performance of each level.
Description
Technical Field
The invention belongs to the technical field of optical signal processing, and particularly relates to a flexible and adjustable multi-level all-optical 2R regeneration (reshaping and reamplifying) device.
Background
In an optical fiber communication system, an optical signal is affected by degradation factors such as optical fiber dispersion, optical fiber nonlinear effect, Amplified Spontaneous Emission (ASE) noise of an optical amplifier, and inter-channel crosstalk during transmission in an optical fiber, so that the optical signal is degraded, and the data transmission rate and the network coverage of the optical fiber communication system are further limited. Therefore, it is necessary to perform a reproduction process on the degraded optical signal. Although conventional optical-electrical-optical regeneration schemes are well established, there is an "electronic bottleneck" problem that makes it difficult to meet the ever-increasing demand for higher speed data transmission. All-optical regeneration technology is considered to be the ultimate goal to solve this problem.
On the other hand, with the explosion of services such as cloud computing, big data and mobile internet, the optical fiber network as an infrastructure is forced to adopt a high-order modulation format with higher channel utilization rate so as to provide larger transmission capacity. In consideration of the increasing adoption of Pulse Amplitude Modulation (PAM) format for high-speed transmission in data centers and the application requirements of long-distance communication between data centers, the problem of regeneration of optical PAM signals is inevitably encountered in the future.
At present, all-optical regeneration device design schemes are mostly for on-off keying (OOK) signals and cannot be directly used for regeneration of PAM signals. In the prior art, for example, a light-controlled optical PAM signal regeneration device with publication number CN106972890A published in 2017, month 07 and day 21 is named as "a light-controlled optical PAM signal regeneration device", which is a PAM regeneration device based on a mach-zehnder interferometer (MZI) and a nonlinear optical fiber loop mirror (NOLM), and has a common characteristic that an oscillation amplitude of a Power Transfer Function (PTF) curve of the device is larger and larger along with an increase of input power, only one or a limited flat shaping region can be obtained, and a regeneration effect difference of each level of an optical PAM signal is large, so that a reproducible level number is limited. In addition, the optical coupler used in these schemes has extreme parameter values (such as straight-through efficiency), and is not easy to obtain products meeting corresponding requirements.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provide a flexible and adjustable multi-level all-optical 2R regeneration device, so that after a deteriorated optical PAM signal is processed by the 2R regeneration device, an amplified high-quality optical PAM signal is obtained, meanwhile, the regeneration level is flexible and adjustable, optical PAM signals with any level number can be shaped, the regeneration performance of each level has good consistency, and the problem of extreme value of the straight-through efficiency (splitting ratio) of an optical coupler is solved.
In order to achieve the above purpose, the present invention provides a flexible and adjustable multi-level all-optical 2R regeneration device, which is characterized by comprising two optical paths, namely a horizontal polarization optical path and a vertical polarization optical path, wherein the horizontal polarization optical path comprises an optical amplifier, a first polarization controller, a horizontal linear polarizer, a first 2 × 1 optical coupler, a high nonlinear optical fiber, and a second 2 × 1 optical coupler; the vertical polarization light path comprises a laser, a second polarization controller, a vertical linear polarizer, a 1 × 2 optical coupler and an optical phase shifter;
for a horizontal polarization optical path, a deteriorated multilevel optical PAM signal to be regenerated is amplified by an optical amplifier, the polarization direction of the deteriorated multilevel optical PAM signal is adjusted to be consistent with the polarization direction of a horizontal linear polarizer by a first polarization controller to obtain the horizontal polarization deteriorated multilevel optical PAM signal, and then the horizontal polarization deteriorated multilevel optical PAM signal is injected into an input port 1 of a first 2 x 1 optical coupler;
for a vertical polarization light path, continuous auxiliary light is emitted by a laser, the polarization direction of the continuous auxiliary light is adjusted to be consistent with that of a vertical linear polarizer through a second polarization controller to obtain vertical polarization auxiliary light, then the vertical polarization auxiliary light is injected into a 1 x 2 optical coupler to divide the vertical polarization auxiliary light into two paths, one path of vertical polarization auxiliary light is injected into an input port 2 of a first 2 x 1 optical coupler in a horizontal polarization light path, and the other path of vertical polarization auxiliary light is injected into an optical phase shifter;
in a first 2 × 1 optical coupler of a horizontal polarization optical path, a horizontal polarization-degraded multi-level optical PAM signal and vertical polarization auxiliary light are combined to obtain a combined optical signal, and the combined optical signal is injected into a high-nonlinearity optical fiber to generate a nonlinear effect: the vertical polarization auxiliary light is subjected to the cross phase modulation effect of the horizontal polarization degraded multi-level optical PAM signal, so that the phase of the vertical polarization auxiliary light is changed, and the phase is changed, namely phase shift
Where ∈ is proportional to the sign, B is a coefficient related to the loss and nonlinear coefficient of the highly nonlinear optical fiber, G is the gain of the optical amplifier in the horizontal polarization optical path, and P isinFor the power of the degraded multi-level optical PAM signal to be regenerated, L is the length of the highly nonlinear optical fiber; the coupled optical signal after nonlinear action is injected into the input port 1 of the second 2 x 1 optical coupler, which includes a phase shift
The vertical polarization auxiliary optical signal and the phase-shifted horizontal polarization degraded multi-level optical PAM signal;
the optical phase shifter in the vertical polarization light path carries out certain phase shift on the other vertical polarization auxiliary light
Then, the optical signal is injected into the input port 2 of the second 2 × 1 optical coupler of the horizontal polarization optical path;
phase shift in the coupled optical signal after nonlinear action in the second 2 x 1 optical coupler of the horizontally polarized optical path
The vertical polarization auxiliary optical signal and the phase shifter have a certain phase shift
The vertical polarization auxiliary optical signal is subjected to interference coupling to obtain a coupled vertical polarization auxiliary optical signal with power
Wherein ∈ is proportional to the symbol, PyPower of the continuous auxiliary light; meanwhile, in the second 2 x 1 optical coupler of the horizontal polarization optical path, the coupled vertical polarization auxiliary optical signal and the horizontal polarization degradation multilevel optical PAM signal after phase shift in the coupled optical signal after nonlinear action are subjected to power superposition and a regenerated optical PAM signal is output, and the power P of the regenerated optical PAM signal isoutComprises the following steps:
wherein the content of the first and second substances,
the power of the horizontal polarization degraded multi-level optical PAM signal after phase shifting is represented by a proportionality coefficient.
The invention aims to realize the following steps:
according to the flexibly adjustable multi-level all-optical 2R regeneration device, a deteriorated multi-level optical PAM signal to be regenerated is amplified in an optical amplifier, and the direction of a horizontal linear polarizer is adjusted to be consistent by a first polarization controller, so that the horizontal polarization deteriorated multi-level optical PAM signal is obtained; adjusting the polarization direction of continuous auxiliary light emitted by the laser to be consistent with the polarization direction of the vertical linear polarizer through a second polarization controller to obtain vertical polarization auxiliary light; the horizontal polarization-degraded multi-level optical PAM signal and the vertical polarization auxiliary light are combined in a first 2 x 1 optical coupler to obtain a combined optical signal. And injecting the combined optical signal into the high-nonlinearity optical fiber, wherein the vertical polarization auxiliary light is subjected to the cross phase modulation effect of the horizontal polarization degradation multi-level optical PAM signal, so that the phase of the vertical polarization auxiliary light is changed, and the changed vertical polarization auxiliary optical signal is in interference coupling with the vertical polarization auxiliary optical signal after a phase shift in the vertical polarization optical path, so that the coupled vertical polarization auxiliary optical signal and the horizontal polarization degradation multi-level optical PAM signal after the phase shift in the coupled optical signal after the nonlinear effect are subjected to power superposition to obtain a regenerated optical PAM signal. In the regenerated optical PAM signal, the vertical polarization auxiliary optical signal is modulated by the Power of the degraded multi-level optical PAM signal, so that a Power Transfer Function (PTF) curve of which the Power of the regenerated optical PAM signal, namely the output Power, is increased by steps along with the increase of the Power of the degraded multi-level optical PAM signal, namely the input Power, is formed, and the degraded optical PAM signal is processed by the device disclosed by the invention to obtain an amplified high-quality optical PAM signal. Meanwhile, the gain of the optical amplifier is increased, and the number of steps of a power transfer function curve is increased, so that the regeneration level is flexible and adjustable, and the optical PAM signal with any level number can be shaped. The regeneration working point can be changed by adjusting the phase shift of the optical phase shifter, the device can adapt to different input degraded optical PAM signals, and simultaneously, the regeneration performance of each level has good consistency corresponding to the flat area of the curve, and the problem of extreme dereferencing of the straight-through efficiency (splitting ratio) of the optical coupler can be solved.
Drawings
FIG. 1 is a schematic structural diagram of a specific embodiment of the flexible and adjustable multi-level all-optical 2R regeneration device;
FIG. 2 is a graph of PTF curves at different gains of an optical amplifier;
FIG. 3 is a PTF graph at different assist optical powers;
FIG. 4 is a graph of PTF for different values of phase shift of the phase shifter;
FIG. 5 is a power waveform diagram of a degraded multi-level optical PAM signal to be regenerated;
fig. 6 is a power waveform diagram of the regenerated optical PAM signal.
Detailed Description
The following description of the embodiments of the present invention is provided in order to better understand the present invention for those skilled in the art with reference to the accompanying drawings. It is to be expressly noted that in the following description, a detailed description of known functions and designs will be omitted when it may obscure the subject matter of the present invention.
Fig. 1 is a schematic structural diagram of a specific embodiment of the flexible and adjustable multilevel all-optical 2R regeneration device.
In this embodiment, as shown in fig. 1, the flexible and adjustable multi-level all-optical 2R regeneration apparatus of the present invention is composed of two optical paths, i.e., a horizontal polarization optical path 1 and a vertical polarization optical path 2, wherein the horizontal polarization optical path 1 sequentially includes an optical amplifier 101, a first polarization controller 102, a horizontal linear polarizer 103, a first 2 × 1 optical coupler 104, a high nonlinear optical fiber 105, and a second 2 × 1 optical coupler 106; the vertically polarized light path 2 includes a laser 201, a second polarization controller 202, a vertical linear polarizer 203, a 1 × 2 optical coupler 204, and an optical phase shifter 205 in this order. Regarding two optical paths forming the regeneration device, a horizontal polarization optical path is used for degrading multi-level optical PAM signal transmission, performs cross phase modulation with vertical polarization auxiliary light, and then performs interference coupling with the vertical polarization auxiliary light after phase shifting to obtain a regenerated optical PAM signal; the vertical polarization optical path is used for generating vertical polarization continuous light and vertical polarization auxiliary light after phase shifting so as to carry out cross phase modulation and interference coupling.
For the horizontal polarization optical path 1, the degraded multi-level optical PAM signal S to be regeneratedPAMAmplified by the optical amplifier 101 to obtain an amplified deteriorated multilevel optical PAM signal SPAM_ADegraded multi-level optical PAM signal SPAM_AThe polarization direction of the PAM signal is adjusted to be consistent with that of a horizontal linear polarizer 103 by a first polarization controller 102, and a horizontal polarization degraded multi-level optical PAM signal S is obtainedPAM_HThen is injected intoTo the input port 1 of the first 2 x 1 optical coupler 104. The adjustment of the polarization direction can maximize the output efficiency of the horizontal linear polarizer, and simultaneously, the degraded multi-level optical PAM signal to be regenerated is converted into a horizontal polarization degraded multi-level optical PAM signal through the processing of the steps.
For a vertically polarized light path, the laser 201 emits a continuous auxiliary light SFThe polarization direction of the auxiliary light S is adjusted to be consistent with the polarization direction of the vertical linear polarizer 203 by the second polarization controller 202 to obtain the vertical polarization auxiliary light SF_VAnd then injected into the 1 × 2 optical coupler 204 to vertically polarize the auxiliary light SF_VDivided into two paths, one path of vertical polarized auxiliary light SF_V1The input port 2 of the first 2 × 1 optical coupler 104 injected into the horizontal polarization optical path 1, and the other path of vertically polarized auxiliary light SF_V2Into the optical phase shifter 205.
In the first 2 × 1 optical coupler 104 of the horizontal polarization optical path 1, the horizontal polarization deteriorated multilevel optical PAM signal SPAM_HAnd vertically polarized auxiliary light SF_V1Combining the beams to obtain a combined optical signal SCBeam combining optical signal SCInjection into the highly nonlinear fiber 105 takes place a nonlinear effect: vertically polarized auxiliary light SF_V1Multi-level optical PAM signal S subject to horizontal polarization degradationPAM_HBy cross-phase modulation, the phase of which is changed, i.e. phase shift
Where ∈ is proportional to the sign, B is a coefficient relating to the loss and nonlinear coefficient of the highly nonlinear optical fiber 105, G is the gain of the optical amplifier 101 in the horizontally polarized optical path 1, and P isinDegraded multi-level optical PAM signal S to be regeneratedPAML is the length of the highly nonlinear fiber 105. Beam combining optical signal S after nonlinear actionC_NInjected into the input port 1 of the second 2 x 1 optical coupler 106, which includes a phase shift
Of vertically polarized auxiliary light signal S'F_V1And phase shifted horizontal polarization degradation multi-levelLight PAM Signal S'PAM_H；
The optical phase shifter 205 in the vertically polarized light path 2 is used for the other vertically polarized auxiliary light SF_V2With a certain phase shift
Then, a phase-shifted vertically polarized auxiliary light S 'was obtained'F_V2Input port 2 of the second 2 × 1 optical coupler 106 injected into the horizontally polarized optical path 1;
in the second 2 × 1 optical coupler 106 of the horizontal polarization beam path 1, the phase shift in the coupled optical signal after the nonlinear action
Of vertically polarized auxiliary light signal S'F_V1With a certain phase shift from the phase shifter
Rear vertically polarized auxiliary light signal S'F_V2Interference coupling is carried out to obtain a coupled vertical polarization auxiliary light signal S'F_CPower of it
Wherein ∈ is proportional to the symbol, PyPower of the continuous auxiliary light; meanwhile, in the second 2 × 1 optical coupler 106 of the horizontal polarization optical path 1, the vertically polarized auxiliary optical signal S 'is coupled'F_CAnd a phase-shifted horizontal polarization-degraded multilevel optical PAM signal S 'in the coupled optical signal after nonlinear action'PAM_HPerforming power superposition and outputting regenerated optical PAM signal SRPAMPower P ofoutComprises the following steps:
wherein the content of the first and second substances,
is a horizontal polarization-degraded multi-level optical PAM signal S'PAM_HA is a scaling factor.
In this embodiment, as shown in fig. 1, the signal processing procedure of the present invention is as follows:
in the horizontal polarization optical path 1, a deteriorated multi-level optical PAM signal S to be regenerated is setPAMHas a power (instantaneous power) of PinAfter being amplified by the optical amplifier 101 (with a gain of G), horizontally polarized by the first polarization controller 102 and the horizontal linear polarizer 103, the obtained horizontally polarization-degraded multi-level optical PAM signal SPAM_HPower is changed into Px＝GPinAnd then injected into the highly nonlinear optical fiber 105 through the first 2 x 1 optical coupler 104.
In the vertically polarized light path 2, the laser 201 is an auxiliary light source for realizing 2R regeneration function, and emits continuous auxiliary light SFAfter being vertically polarized by the second polarization controller 202 and the vertical linear polarizer 203, the vertically polarized auxiliary light S is obtainedF_VThe 1 × 2 optical coupler 204 divides the light into two paths, one path of the auxiliary light S with straight polarizationF_V1Injected into the input port 2 of the first 2 × 1 optical coupler 104, injected into the high nonlinear optical fiber 105 through the first 2 × 1 optical coupler 104, and the other path of the linearly polarized auxiliary light SF_V2Into the optical phase shifter 205, the optical phase shifter 205 acting to adjust the phase of the corresponding optical field, i.e. to introduce a phase shift
The highly nonlinear optical fiber 105 has two roles, one is to make the horizontal polarization degrade the multilevel optical PAM signal SPAM_HThe signal power is not changed by the self-phase modulation effect of the high nonlinear fiber at the moment; another effect is to degrade the multi-level optical PAM signal S by means of horizontal polarizationPAM_HPower P ofxThe cross phase modulation effect of (2) makes the auxiliary light S vertically polarizedF_V1Is changed in phase, is shifted in phase
Where ∈ is proportional to the sign, and B is a coefficient relating to the loss and nonlinear coefficient of the highly nonlinear optical fiber 105.
Coupled optical signal S after nonlinear actionC_NInjected into the input port 1 of the second 2 x 1 optical coupler 106, which includes a phase shift
Of vertically polarized auxiliary light signal S'F_V1And a phase-shifted horizontal polarization-degraded multilevel optical PAM signal S'PAM_H. Simultaneously, the phase-shifted vertically polarized auxiliary light S'F_V2And is injected into the input port 2 of the second 2 × 1 optical coupler 106 of the horizontally polarized optical path 1.
The second 2 × 1 optical coupler 106 functions to interfere two optical signals having the same polarization and to superpose the power of two optical signals having different polarizations. Since only a single path of horizontally polarized signal passes through the second 2 × 1 optical coupler 106, the power of the horizontally polarized light output by the second 2 × 1 optical coupler 106 is proportional to GPinI.e. by
The two paths of vertically polarized light with the same polarization interfere in the second 2 × 1 optical coupler 106, and the output power is
Wherein P isyIs a continuous auxiliary optical power. The second 2 × 1 optical coupler 106 functions to add power to two optical signals with different polarizations, in addition to interfering the two optical signals with the same polarization. Therefore, the total output optical power of the regeneration device of the invention is composed of the output optical powers of the horizontal polarization light path and the vertical polarization light path, that is
A is a proportionality coefficient. Therefore, the adjusting function of the optical amplifier gain, the auxiliary optical power, the optical fiber length, the optical phase shifter and the like on the PTF curve can be intuitively analyzed.
The shaping characteristics of the flexible and adjustable multilevel all-optical 2R regeneration device are generally described by using a step-type input/output Power Transfer Function (PTF). The best noise suppression performance is achieved when different levels of the input multi-level optical signal are aligned with different flat areas of output power. A typical PTF curve that can be achieved by the present invention is shown in fig. 2. The invention adopts the optical amplifier with adjustable gain, and can change the step power of the regeneration device by adjusting the gain of the optical amplifier, thereby realizing the regeneration of the optical PAM signal with any level number in a certain input power range. As can be seen from fig. 2, under the other conditions, when the gain of the optical amplifier is increased to twice that of the original gain (curve 1) (the gain is increased from 10dB to 13dB), the PTF curve is changed to curve 2, that is, the number of regeneration steps is increased by one time within the same input power range, so that the optical PAM signal regeneration with more levels can be performed, and the power of the output optical PAM signal, that is, the regenerated optical PAM signal is also increased by one time (3 dB). It is worth pointing out that, the flexible and adjustable multilevel all-optical 2R regeneration device of the present invention can regenerate optical PAM signals of any number of levels, and each level has the same PTF flatness and the same good noise suppression capability.
The continuous optical frequency emitted by the laser in the vertical polarization optical path is basically the same as the carrier frequency of the input PAM signal, and the given length of the high nonlinear optical fiber can be matched by properly adjusting the continuous optical power emitted by the laser, and meanwhile, the multilevel all-optical regeneration performance of the system is kept; in other words, when the high nonlinear fiber length is selected, the regeneration device can be operated in a better shaping state by adjusting the power of the continuous auxiliary light. When the continuous auxiliary light power emitted by the laser is doubled, the required length of the high nonlinear optical fiber can be reduced to half of the original length, and a plurality of flat shaping areas still exist. As shown in fig. 3, the power of the auxiliary light is increased from 23dBm to 26dBm, the length of the optical fiber is decreased from 1km to 0.5km, and the PTF curve has a certain change, so that the regeneration device can be operated in a better shaping state by adjusting the power of the continuous auxiliary light.
The flexibly adjustable multi-level all-optical 2R regeneration device can flexibly adapt to the reproducible working point of the input degraded multi-level optical PAM signal by adjusting the phase shift of the optical phase shifter in the vertical polarization light path without redesigning the all-optical 2R regeneration device. Furthermore, the shaping performance of the whole device is not changed in the process of adjusting the optical phase shifter. As shown in fig. 4, the regenerative operating point transmits a shift when the phase shift changes from 135 ° to 90 °.
In this example, for the purpose of illustrating the implementation of the flexible and tunable multi-level all-optical 2R regeneration device of the present invention, a commercial highly nonlinear optical fiber with a loss factor α of 0.21km is selected-1The nonlinear coefficient γ is 10W-1(ii) km; the continuous light frequency emitted by the laser is 193.1 THz; the feed-through efficiency of both the 2 x 1 and 1 x 2 optical couplers was 50%.
In this embodiment, the specific implementation flow of the flexible and adjustable multilevel all-optical 2R regeneration device of the present invention is as follows:
(1) build flexible adjustable multi-level all-optical 2R regeneration device
The construction was carried out as shown in figure 1. The gain of the optical amplifier, the output optical power of the laser and the phase shift of the phase shifter can be adjusted.
(2) Adjusting the polarization state of the horizontal and vertical polarized light paths
In order to allow the two light paths forming the device to operate properly, a polarization analyzer is connected to the output of the second 2 × 1 optical coupler 106 and is used to adjust the light polarization states of the two light paths to be orthogonal. Firstly, turning off the laser 201, inputting continuous light with certain power from the input end of the optical amplifier 101, adjusting the first polarization controller 102 behind the optical amplifier 101 to make the optical power displayed by the polarization analyzer reach the maximum, and simultaneously recording the polarization state at the moment; the optical amplifier 101 is turned off, the laser 201 is turned on, the vertical linear polarizer 203 is adjusted to make the polarization state displayed by the polarization analyzer orthogonal to the previous one, and then the second polarization controller 202 of this optical path is adjusted to maximize the output power. The debugging of the device is completed, and normal work can be ensured.
(3) Adjusting the power of the continuous auxiliary light, optimizing the PTF curve of the system
For the situation of a given length of the high-nonlinearity optical fiber, to realize the all-optical 2R regeneration function, the power of the continuous auxiliary light needs to be adjusted to match the high-nonlinearity optical fiber, so that the PTF curve of the continuous auxiliary light can appear in a platform area, and the process needs to be repeatedly adjusted to be completed. When a 0.5km length of highly nonlinear fiber is used, the auxiliary optical power is 26dBm, and flat regions of multiple levels can appear, as shown in fig. 3.
(4) Adjusting gain of optical amplifier to determine number of reproducible levels
Adjusting the gain of the optical amplifier 101 can change the step power of the regeneration device, thereby realizing regeneration of optical PAM signals of any level number within a certain power range. When the gain of the optical amplifier 101 is doubled, the output power is doubled and the number of reproduction steps is doubled within the same input power range, and the number of reproduction levels is naturally doubled, as shown in fig. 2.
(5) Adjusting the optical phase shifter to complete the matching of the working points
By adjusting the phase shift of the optical phase shifter 205 in the vertically polarized light path, the reproducible operating point of the input degraded PAM signal can be flexibly adapted. When the phase shift is
The PTF curve is shown as curve 1 in FIG. 4, and if the phase shift is reduced by 45 °, the phase shift is
The PTF curve changes to curve 2 and the level operating point of the regenerating device changes, thereby accommodating different inputs of degraded multilevel optical PAM signals. Meanwhile, when the high and low levels of the input degraded multi-level optical PAM signal correspond to a flat region of the output power, the noise level does not exceed the flat region, and good regeneration performance can be obtained.
(6) Comparing the input and output waveforms to simulate the all-optical 2R regeneration function.
Through the steps, a set of optimized device parameters can be obtained finally, for example, the continuous optical power generated by the laser is 26dBm, the amplification factor G of the optical amplifier is 10dB, and the optical phase shifter
When the length of the high nonlinear optical fiber is 0.5km, the all-optical 2R regeneration of a degraded PAM-4 signal can be realized. As shown in fig. 5, the input degraded multi-level Pulse Amplitude Modulation (PAM) signal has a duty ratio of 0.5, and input powers of 0mW, 399mW, 798mW, and 1197mW for respective levels. When the high and low levels of the input optical signal match the regeneration operating point, the input signal level is perfectly aligned with the flat area of the output power, and the best noise suppression performance can be achieved, with the output waveform as shown in fig. 6. As can be seen from the input waveform diagram 5 and the output waveform diagram 6, the noise at each level is suppressed equally well, and the reproduced output signal also gains.
Although illustrative embodiments of the present invention have been described above to facilitate the understanding of the present invention by those skilled in the art, it should be understood that the present invention is not limited to the scope of the embodiments, and various changes may be made apparent to those skilled in the art as long as they are within the spirit and scope of the present invention as defined and defined by the appended claims, and all matters of the invention which utilize the inventive concepts are protected.
Claims (1)
1. A flexible and adjustable multi-level all-optical 2R regeneration device is characterized by comprising a horizontal polarization light path and a vertical polarization light path, wherein the horizontal polarization light path comprises an optical amplifier, a first polarization controller, a horizontal linear polarizer, a first 2 x 1 optical coupler, a high nonlinear optical fiber and a second 2 x 1 optical coupler; the vertical polarization light path comprises a laser, a second polarization controller, a vertical linear polarizer, a 1 × 2 optical coupler, an optical phase shifter and a second 2 × 1 optical coupler;
for a horizontal polarization optical path, a deteriorated multilevel optical PAM signal to be regenerated is amplified by an optical amplifier, the polarization direction of the deteriorated multilevel optical PAM signal is adjusted to be consistent with the polarization direction of a horizontal linear polarizer by a first polarization controller to obtain the horizontal polarization deteriorated multilevel optical PAM signal, and then the horizontal polarization deteriorated multilevel optical PAM signal is injected into an input port 1 of a first 2 x 1 optical coupler;
for a vertical polarization light path, continuous auxiliary light is emitted by a laser, the polarization direction of the continuous auxiliary light is adjusted to be consistent with that of a vertical linear polarizer through a second polarization controller to obtain vertical polarization auxiliary light, then the vertical polarization auxiliary light is injected into a 1 x 2 optical coupler to divide the vertical polarization auxiliary light into two paths, one path of vertical polarization auxiliary light is injected into an input port 2 of a first 2 x 1 optical coupler in a horizontal polarization light path, and the other path of vertical polarization auxiliary light is injected into an optical phase shifter;
in a first 2 × 1 optical coupler of a horizontal polarization optical path, a horizontal polarization-degraded multi-level optical PAM signal and vertical polarization auxiliary light are combined to obtain a combined optical signal, and the combined optical signal is injected into a high-nonlinearity optical fiber to generate a nonlinear effect: the vertical polarization auxiliary light is subjected to the cross phase modulation effect of the horizontal polarization degraded multi-level optical PAM signal, so that the phase of the vertical polarization auxiliary light is changed, and the phase is changed, namely phase shift
Where ∈ is proportional to the sign, B is a coefficient related to the loss and nonlinear coefficient of the highly nonlinear optical fiber, G is the gain of the optical amplifier in the horizontal polarization optical path, and P isinFor the power of the degraded multi-level optical PAM signal to be regenerated, L is the length of the highly nonlinear optical fiber; the coupled optical signal after nonlinear action is injected into the input port 1 of the second 2 x 1 optical coupler, which includes a phase shift
The vertical polarization auxiliary optical signal and the phase-shifted horizontal polarization degraded multi-level optical PAM signal;
the optical phase shifter in the vertical polarization light path carries out certain phase shift on the other vertical polarization auxiliary light
Then, the optical signal is injected into the input port 2 of the second 2 × 1 optical coupler of the horizontal polarization optical path;
phase shift in the coupled optical signal after nonlinear action in the second 2 x 1 optical coupler of the horizontally polarized optical path
The vertical polarization auxiliary optical signal and the phase shifter have a certain phase shift
The vertical polarization auxiliary optical signal is subjected to interference coupling to obtain a coupled vertical polarization auxiliary optical signal with power
Wherein ∈ is proportional to the symbol, PyPower of the continuous auxiliary light; meanwhile, in the second 2 x 1 optical coupler of the horizontal polarization optical path, the coupled vertical polarization auxiliary optical signal and the horizontal polarization degradation multilevel optical PAM signal after phase shift in the coupled optical signal after nonlinear action are subjected to power superposition and a regenerated optical PAM signal is output, and the power P of the regenerated optical PAM signal isoutComprises the following steps:
wherein the content of the first and second substances,
the power of the horizontal polarization degraded multi-level optical PAM signal after phase shifting is represented by a proportionality coefficient.
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| CN201810213738.4A CN108599855B (en) | 2018-03-15 | 2018-03-15 | Flexible and adjustable multi-level all-optical 2R regeneration device |
| PCT/CN2018/086080 WO2019174117A1 (en) | 2018-03-15 | 2018-05-08 | Flexibly adjustable multi-level all-optical 2r regeneration apparatus |
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| CN201810213738.4A CN108599855B (en) | 2018-03-15 | 2018-03-15 | Flexible and adjustable multi-level all-optical 2R regeneration device |
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| CN1321020A (en) * | 2001-05-18 | 2001-11-07 | 清华大学 | Method and device for regenerating return-to-zero code or non-return-to-zero code in high-speed optical communication |
| US7233430B2 (en) * | 2004-12-23 | 2007-06-19 | Massachusetts Institute Of Technology | Multi-channel DPSK receiver |
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| JP2002229081A (en) * | 2001-02-02 | 2002-08-14 | Nec Corp | All-optical light signal reproduction method and device |
| CN1375957A (en) * | 2001-03-15 | 2002-10-23 | 朗迅科技公司 | Delay interference wavelength conversion and/or 2R regenerator |
| JP2009182888A (en) * | 2008-01-31 | 2009-08-13 | Fujitsu Ltd | Optical receiving unit compatible with dqpsk polarized wave multiplexing scheme |
| CN101695011B (en) * | 2009-10-28 | 2012-11-21 | 天津大学 | Method and device for high-speed multi-channel all-optical 3R regeneration |
| CN102185657A (en) * | 2011-04-18 | 2011-09-14 | 电子科技大学 | Full-optical 3R regeneration device based on magnetically controlled optical fiber parameter oscillator |
| CN103117812B (en) * | 2013-01-24 | 2015-08-05 | 华中科技大学 | A kind of regenerator being applicable to WDM-DPSK light signal |
| CN103780308B (en) * | 2014-01-13 | 2017-01-25 | 电子科技大学 | Multi-wavelength all-optical regenerative device capable of inhibiting crosstalk and method thereof |
| CN105490748B (en) * | 2015-11-25 | 2018-01-12 | 电子科技大学 | A kind of multi-wavelength all-optical regeneration device based on code conversion |
| CN106972890B (en) * | 2017-03-10 | 2019-06-14 | 电子科技大学 | A kind of light-operated smooth PAM signal reproducing apparatus |
| CN107579777B (en) * | 2017-08-14 | 2019-09-24 | 电子科技大学 | A kind of full light regenerator self-reacting device |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN1321020A (en) * | 2001-05-18 | 2001-11-07 | 清华大学 | Method and device for regenerating return-to-zero code or non-return-to-zero code in high-speed optical communication |
| US7233430B2 (en) * | 2004-12-23 | 2007-06-19 | Massachusetts Institute Of Technology | Multi-channel DPSK receiver |
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