CN113267914A - Electro-optical modulator closed-loop nonlinear compensation system based on eye pattern monitoring - Google Patents
Electro-optical modulator closed-loop nonlinear compensation system based on eye pattern monitoring Download PDFInfo
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- G—PHYSICS
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- 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
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- G—PHYSICS
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- 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
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Abstract
The invention discloses an electro-optic modulator closed-loop nonlinear compensation system based on eye pattern monitoring, and belongs to the field of photoelectric chips. The method comprises the following steps: the monitoring module is used for detecting the intensity of an output optical signal of the electro-optical modulator in real time and converting the intensity into an electric signal; the eye pattern monitoring module is used for converting the electric signal into an eye pattern; the adaptive nonlinear compensation module is used for judging whether the current eye pattern level is uniformly distributed or not, and if the current eye pattern level is not uniform, adaptively adjusting predistortion parameters to enable the eye pattern level to tend to be uniform; and judging whether the current eye pattern sub-eye patterns are uniformly and maximally distributed, if not, adaptively adjusting the FFE coefficient to enable the eye pattern sub-eye patterns to tend to be uniform, and if so, continuously adjusting the FFE coefficient to enable the uniform sub-eye patterns to tend to be maximum. According to the invention, the predistortion coefficient and the FFE coefficient are automatically adjusted through the self-adaptive nonlinear compensation module, so that the optical PAM eye diagram with uniform level distribution, uniform sub-eye diagram distribution and maximum distribution is realized, manual adjustment is avoided, and the application requirements of a large-scale electro-optical modulator are met.
Description
Technical Field
The invention belongs to the field of photoelectric chip design, and particularly relates to an electro-optical modulator closed-loop nonlinear compensation system based on eye pattern monitoring.
Background
The electro-optical modulator has the advantages of high modulation bandwidth, low energy consumption, easiness in large-scale integration and the like, and is widely applied to the fields of data centers, wireless communication and the like. To further increase the data rate of the electro-optical modulator, a Pulse Amplitude Modulation (PAM) is usually used to convert a Non Return to Zero (NRZ) signal with only 2 levels into a PAM signal with multiple levels, so as to achieve the increase of the data rate. As shown in fig. 1, in order to ensure stable data transmission, it is generally required that the eye pattern area between multiple levels in the PAM signal is kept uniform and as large as possible, so as to ensure that the maximum signal-to-noise ratio and lower error rate are achieved at the same modulation amplitude. When the electro-optical modulator is driven by the driver by the electric PAM signals with uniformly distributed eye patterns, the transmission characteristics of the electro-optical modulator have a nonlinear corresponding relation, so that the eye patterns of the optical PAM signals with non-uniform levels can be caused, namely the static nonlinear effect of the electro-optical modulator; meanwhile, as the electro-optical modulator has different electro-optical modulation bandwidths at different levels, the conversion process between the different levels is different, so that different inter-symbol crosstalk is generated at different levels, which causes the eye pattern shape of the PAM signal to be deteriorated, i.e. the dynamic nonlinear effect of the electro-optical modulator.
In order to compensate for the static non-linear effect of the electro-optical modulator, in the existing work, the electrical PAM signal is usually pre-distorted before the driver, so that the pre-distorted electrical PAM modulation signal is loaded to the electro-optical modulator through the driver, and then an optical PAM eye pattern with uniform level distribution is output. However, this method requires observing the eye pattern shape off-chip with a test instrument and manually adjusting the predistortion parameters to achieve uniform optical eye pattern output. Manual adjustment, when applied to large-scale electro-optic modulator arrays, results in significant labor costs due to the extensive manual handling procedures required for manual adjustment, and once set, is difficult to dynamically adjust again. Therefore, the static nonlinear compensation scheme based on the manual adjustment mode is not suitable for large-scale electro-optical modulator application.
In order to compensate for the dynamic nonlinear effect of the electro-optical modulator, in the prior art, the electrical PAM signal is usually equalized before the driver, such as Feed Forward Equalization (FFE), so as to reduce the inter-symbol crosstalk of the output optical eye pattern of the electro-optical modulator. However, this method still requires observing the eye pattern shape off-chip with a test instrument and manually adjusting the FFE coefficients to achieve less inter-symbol interference. Similar to the static nonlinear compensation scheme based on the manual adjustment mode, the dynamic nonlinear compensation scheme based on the manual adjustment is also not suitable for large-scale electro-optical modulator application.
Since the static nonlinear effect and the dynamic nonlinear effect change slowly with the aging of the device, the predistortion parameters and FFE coefficients set manually still need long-term manual operation to ensure a stable working state during the use process, and the device may need to be suspended during each manual adjustment process, thereby increasing the use cost.
Disclosure of Invention
Aiming at the defects of bottlenecks and improvement requirements in the electro-optical modulator nonlinear compensation method based on manual adjustment predistortion and FFE in the prior art, the invention provides an electro-optical modulator closed-loop nonlinear compensation system based on eye pattern monitoring, and aims to realize stable compensation of static nonlinear effects, dynamic nonlinear effects and the like of the electro-optical modulator.
To achieve the above object, according to a first aspect of the present invention, there is provided an electro-optical modulator closed-loop nonlinear compensation system based on eye monitoring, the electro-optical modulator being driven by a driver to modulate output light of a light source and generate an optical signal varying with a PAM signal, an input signal of the driver being the PAM signal processed by a predistortion/FFE module, the system comprising:
the monitoring module is used for detecting the intensity of the optical signal output by the electro-optical modulator in real time, converting the intensity of the optical signal into an electric signal and sending the electric signal to the eye pattern monitoring module;
the eye pattern monitoring module is used for converting the received electric signals into an eye pattern and sending the eye pattern to the self-adaptive nonlinear compensation module;
the adaptive nonlinear compensation module is used for judging whether the level of the current eye pattern is uniformly distributed, and if the level of the current eye pattern is not uniform, adaptively adjusting predistortion parameters in the predistortion/FFE module to enable the level of the eye pattern to tend to be uniform; and if the sub-eye patterns are uniform but not maximum, continuing to adaptively adjust the FFE coefficient in the predistortion/FFE module to enable the uniform sub-eye patterns to tend to be maximum.
To achieve the above object, according to a second aspect of the present invention, there is provided an electro-optical modulator array closed-loop nonlinear compensation system based on eye monitoring, the electro-optical modulator array includes a plurality of electro-optical modulators, the electro-optical modulators correspond to a predistortion/FFE module and a driver one-to-one, the electro-optical modulators are driven by the corresponding drivers to modulate output light of a light source and generate an optical signal varying with PAM modulation data, an input signal of the driver is a PAM signal processed by the corresponding predistortion/FFE module, and the system includes:
the multiplexer is used for connecting the eye pattern monitoring module with all the monitoring modules and switching to different monitoring modules each time;
the demultiplexer is used for connecting the self-adaptive nonlinear compensation module and all the predistortion/FFE modules and switching to different predistortion/FFE modules each time;
the monitoring modules are in one-to-one correspondence with the electro-optical modulators and used for detecting the intensity of optical signals output by the corresponding electro-optical modulators in real time, converting the intensity of the optical signals into electric signals and sending the electric signals to the eye pattern monitoring modules;
the eye pattern monitoring module is used for converting the received electric signals into an eye pattern and sending the eye pattern to the self-adaptive nonlinear compensation module;
the adaptive nonlinear compensation module is used for judging whether the level of the current eye pattern is uniformly distributed, and if the level of the current eye pattern is not uniform, adaptively adjusting predistortion parameters in the predistortion/FFE module to enable the level of the eye pattern to tend to be uniform; and if the sub-eye patterns are uniform but not maximum, continuing to adaptively adjust the FFE coefficient in the predistortion/FFE module to enable the uniform sub-eye patterns to tend to be maximum.
Has the advantages that: the closed-loop nonlinear compensation of the electro-optical modulator array is realized by multiplexing the eye pattern monitoring module and the adaptive nonlinear compensation module, namely, the eye pattern monitoring module is connected with the plurality of monitoring modules through the multiplexer, and the adaptive nonlinear compensation module is connected with the plurality of predistortion and FFE modules through the demultiplexer, so that the use of a plurality of eye pattern monitoring and adaptive nonlinear compensation modules is avoided, and further the chip area and the power consumption are saved.
Preferably, the eye pattern monitoring module is periodically turned on, and is turned off after obtaining the optical PAM eye pattern with uniform level distribution, uniform sub-eye pattern distribution and maximum after each turn-on, and the adaptive nonlinear compensation module keeps the output unchanged during the period from the turn-off of the eye pattern monitoring module to the next turn-on.
Has the advantages that: considering that the eye pattern monitoring module has high working frequency and can cause larger power consumption, but the equipment is aged more slowly, the invention provides that after the optical PAM eye pattern with uniform level distribution, uniform sub-eye pattern distribution and maximum is obtained, the eye pattern monitoring module is closed, the output of the self-adaptive nonlinear compensation algorithm module is kept unchanged, and then the eye pattern monitoring module is started regularly to deal with the problem of equipment aging, so that the eye pattern monitoring module works intermittently, and the problem of larger power consumption of the traditional eye pattern monitoring module is solved.
Preferably, when the error rate of a signal received by the receiving end exceeds a preset threshold, the eye pattern monitoring module is turned on, and is turned off after obtaining the optical PAM eye pattern with uniform level distribution, uniform sub-eye pattern distribution and maximum after being turned on, and the adaptive nonlinear compensation module keeps the output unchanged during the period from the turning off of the eye pattern monitoring module to the next turning on of the eye pattern monitoring module.
Has the advantages that: considering that the eye pattern monitoring module has high working frequency and can cause larger power consumption, but the equipment is aged more slowly, the invention provides that after the optical PAM eye pattern with uniform level distribution, uniform sub-eye pattern distribution and maximum is obtained, the eye pattern monitoring module is closed, the output of the self-adaptive nonlinear compensation algorithm module is kept unchanged, and then the eye pattern monitoring module is started to deal with the problem of equipment aging by the fact that the error rate of signals received by a receiving end exceeds a preset threshold value, so that the eye pattern monitoring module works intermittently, and the problem of larger power consumption of the traditional eye pattern monitoring module is solved.
Preferably, the criterion for the PAM signal level distribution to be uniform is as follows: the distance between any adjacent eye levels is equal.
Preferably, the criterion that the sub-eye patterns of the eye pattern are uniformly distributed and largest is as follows: all sub-eye patterns are the same and largest in shape or area.
Preferably, the electro-optical modulator is a ring modulator, a microdisk modulator, or a mach-zehnder modulator.
Generally, by the above technical solution conceived by the present invention, the following beneficial effects can be obtained:
according to the invention, the predistortion coefficient and the FFE coefficient are automatically adjusted through the self-adaptive nonlinear compensation module to realize the optical PAM eye pattern with uniform level distribution, uniform sub-eye pattern distribution and the maximum, so that manual adjustment is avoided, stable compensation of static nonlinear effect, dynamic nonlinear effect and the like of the electro-optical modulator is realized, and the application requirements of large-scale electro-optical modulators are met.
Drawings
FIG. 1 is a PAM signal eye diagram (for example, PAM-4);
FIG. 2 is a schematic diagram of a closed-loop nonlinear compensation system of an electro-optic modulator based on eye monitoring provided by the invention;
FIG. 3 is a schematic diagram of a closed-loop nonlinear compensation method for a ring-shaped electro-optic modulator based on eye monitoring, a photodiode and an adaptive nonlinear compensation algorithm module according to an embodiment;
FIG. 4 is a schematic diagram of a closed-loop nonlinear compensation method for a ring-shaped electro-optic modulator array based on eye monitoring, a photodiode and an adaptive nonlinear compensation algorithm module according to the second embodiment;
fig. 5 is a schematic diagram of a closed-loop nonlinear compensation method of a microdisk electro-optical modulator based on eye monitoring, a photodiode and an adaptive nonlinear compensation algorithm module according to the third embodiment;
FIG. 6 is a schematic diagram of a closed-loop nonlinear compensation method for a microdisk electro-optical modulator array based on eye diagram monitoring, a photodiode and an adaptive nonlinear compensation algorithm module according to the fourth embodiment;
FIG. 7 is a schematic diagram of a closed-loop nonlinear compensation method for a Mach-Zehnder electro-optic modulator array based on eye diagram monitoring, a photodiode and an adaptive nonlinear compensation algorithm module according to the fifth embodiment;
fig. 8 is a schematic diagram of a closed-loop nonlinear compensation method for a mach-zehnder electro-optic modulator array based on eye diagram monitoring, a photodiode and an adaptive nonlinear compensation algorithm module according to the sixth embodiment.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. In addition, the technical features involved in the embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.
As shown in fig. 2, the present invention provides an electro-optical modulator closed-loop nonlinear compensation system based on eye monitoring, the electro-optical modulator is driven by a driver to modulate output light of a light source and generate an optical signal varying with a PAM signal, an input signal of the driver is the PAM signal processed by a predistortion/FFE module, the system includes:
and the monitoring module is used for detecting the intensity of the optical signal output by the electro-optical modulator in real time, converting the intensity of the optical signal into an electric signal and sending the electric signal to the eye pattern monitoring module.
And the eye pattern monitoring module is used for converting the received electric signal into an eye pattern and sending the eye pattern to the self-adaptive nonlinear compensation module.
The adaptive nonlinear compensation module is used for judging whether the level of the current eye pattern is uniformly distributed, and if the level of the current eye pattern is not uniform, adaptively adjusting predistortion parameters in the predistortion/FFE module to enable the level of the eye pattern to tend to be uniform; and if the sub-eye patterns are uniform but not maximum, continuing to adaptively adjust the FFE coefficient in the predistortion/FFE module to enable the uniform sub-eye patterns to tend to be maximum.
The above process is continuously iterated, so that static nonlinearity and dynamic nonlinearity are compensated, and finally, the PAM eye pattern with uniform level distribution, uniform sub-eye pattern distribution and maximum amplitude is obtained.
The invention provides an electro-optical modulator array closed-loop nonlinear compensation system based on eye pattern monitoring, wherein the electro-optical modulator array comprises a plurality of electro-optical modulators, the electro-optical modulators correspond to a predistortion/FFE module and a driver one by one, the electro-optical modulators are driven by the corresponding drivers to modulate output light of a light source and generate optical signals changing along with PAM modulation data, and input signals of the drivers are PAM signals processed by the corresponding predistortion/FFE modules, and the system comprises:
and the multiplexer is used for connecting the eye pattern monitoring module with all the monitoring modules and switching to different monitoring modules each time.
And the demultiplexer is used for connecting the self-adaptive nonlinear compensation module with all the predistortion/FFE modules and switching to different predistortion/FFE modules each time.
And the monitoring modules are in one-to-one correspondence with the electro-optical modulators and are used for detecting the intensity of the optical signals output by the corresponding electro-optical modulators in real time, converting the intensity of the optical signals into electric signals and sending the electric signals to the eye pattern monitoring modules.
And the eye pattern monitoring module is used for converting the received electric signal into an eye pattern and sending the eye pattern to the self-adaptive nonlinear compensation module.
The adaptive nonlinear compensation module is used for judging whether the level of the current eye pattern is uniformly distributed, and if the level of the current eye pattern is not uniform, adaptively adjusting predistortion parameters in the predistortion/FFE module to enable the level of the eye pattern to tend to be uniform; and judging whether the sub-eye diagrams of the current eye diagram are uniformly distributed, if not, adaptively adjusting the FFE coefficient in the predistortion/FFE module to enable the sub-eye diagrams of the eye diagram to tend to be uniform.
Preferably, the eye pattern monitoring module is periodically turned on, and is turned off after obtaining the optical PAM eye pattern with uniform level distribution, uniform sub-eye pattern distribution and maximum after each turn-on, and the adaptive nonlinear compensation module keeps the output unchanged during the period from the turn-off of the eye pattern monitoring module to the next turn-on.
Preferably, when the error rate of a signal received by the receiving end exceeds a preset threshold, the eye pattern monitoring module is turned on, and is turned off after obtaining the optical PAM eye pattern with uniform level distribution, uniform sub-eye pattern distribution and maximum after being turned on, and the adaptive nonlinear compensation module keeps the output unchanged during the period from the turning off of the eye pattern monitoring module to the next turning on of the eye pattern monitoring module.
Preferably, the criterion for the PAM signal level distribution to be uniform is as follows: the distance between any adjacent eye levels is equal.
Preferably, the criterion for the even distribution of the sub-eye patterns of the eye pattern is as follows: all sub-eye patterns are the same in shape or area.
Preferably, the electro-optical modulator is a ring modulator, a microdisk modulator, or a mach-zehnder modulator.
Fig. 3 to 8 show a first embodiment, a second embodiment, a third embodiment, a fourth embodiment, a fifth embodiment, and a sixth embodiment according to the present invention, respectively.
Example one
Firstly, a light source sends out an optical signal to enter an annular electro-optic modulator;
inputting PAM modulation data to a predistortion and FFE module;
thirdly, the driver drives the resonance wavelength of the annular electro-optic modulator to change according to the predistortion and the output signal of the FFE module, so that the modulation of the optical signal is realized;
fourthly, the photodiode detects the light intensity change of a download port/through port of the annular electro-optical modulator and converts the light intensity change into an electric signal which changes along with the PAM data;
fifthly, detecting the electric signal changing along with the PAM data by the eye pattern monitoring module, and obtaining eye pattern information;
step six, the self-adaptive nonlinear compensation algorithm module judges whether the PAM signal level is uniformly distributed or not according to the eye pattern information obtained by the eye pattern monitoring module, if not, the predistortion parameter is changed to enable the PAM signal level to tend to be uniform, and if so, the predistortion parameter is kept unchanged; the self-adaptive nonlinear compensation algorithm module judges whether the shapes or the areas of a plurality of sub-eye patterns of the PAM signal at the moment are the same and the largest according to the eye pattern information obtained by the eye pattern monitoring module, if the shapes or the areas of the sub-eye patterns are different, the FFE coefficient is changed to enable the shapes or the areas of the sub-eye patterns to be the same, if the shapes or the areas of the sub-eye patterns are the same but the sub-eye patterns are not the largest, the FFE coefficient is continuously changed to enable the shapes or the areas of the uniform sub-eye patterns to be the largest, and if the shapes or the areas of the uniform sub-eye patterns are the same and the largest, the FFE coefficient is kept unchanged;
and step seven, judging whether the distances among the adjacent eye pattern levels are equal and whether the shapes or the areas of the sub eye patterns are the same and the areas of the sub eye patterns are the largest, and repeating the step one to the step six if the distances are not equal.
The manner in which the predistortion parameters are varied such that the PAM signal level tends to be uniform may be, but is not limited to: an ideal intermediate level position enabling a uniform level distribution is calculated from the lowest and highest levels, and thus the predistortion parameters are changed so that the detected intermediate level approaches the ideal intermediate level position.
The way to change the FFE coefficient such that the sub-eye shapes or areas tend to be the same and largest may be, but is not limited to: the corresponding sub-eye shapes or areas under different FFE coefficients are listed through an exhaustive method, so that the current FFE coefficient is set to be the FFE coefficient in which the sub-eye shapes or areas can be made to approach the same and the maximum.
Example two
Step one, a photodiode output multiplexer and a demultiplexer are switched to a first ring modulator in an N-path ring modulator array;
step two, the light source array sends out multiple paths of optical signals to enter the annular modulator array;
inputting the multi-path PAM modulation data to a predistortion and FFE module array;
fourthly, the driver array drives the resonant wavelength of the annular electro-optic modulator array to change according to the predistortion and the multiple signals output by the FFE module array, so that the modulation of the multiple optical signals is realized;
fourthly, monitoring the light intensity change of a download port/direct port of the annular electro-optical modulator array by the photodiode array and converting the light intensity change into a plurality of paths of electric signals changing along with the PAM data;
sixthly, monitoring the electric signal changed along with the PAM data by the eye pattern monitoring module, and obtaining eye pattern information;
step seven, the self-adaptive nonlinear compensation algorithm module judges whether the PAM signal level is uniformly distributed or not according to the eye pattern information obtained by the eye pattern monitoring module, if not, the predistortion parameter is changed to enable the PAM signal level to tend to be uniform, and if so, the predistortion parameter is kept unchanged; the self-adaptive nonlinear compensation algorithm module judges whether the shapes or the areas of a plurality of sub-eye patterns of the PAM signal at the moment are the same and the largest according to the eye pattern information obtained by the eye pattern monitoring module, if the shapes or the areas of the sub-eye patterns are different, the FFE coefficient is changed to enable the shapes or the areas of the sub-eye patterns to be the same, if the shapes or the areas of the sub-eye patterns are the same but the sub-eye patterns are not the largest, the FFE coefficient is continuously changed to enable the shapes or the areas of the uniform sub-eye patterns to be the largest, and if the shapes or the areas of the uniform sub-eye patterns are the same and the largest, the FFE coefficient is kept unchanged;
step eight, judging whether the distances among the adjacent eye pattern levels are equal and whether the shapes or the areas of the sub eye patterns are the same and the areas of the sub eye patterns are the largest, and if not, repeating the step two to the step seven;
and step nine, switching the photodiode output multiplexer and the demultiplexer to the next annular electro-optical modulator, and repeating the step two to the step eight until the last annular electro-optical modulator.
EXAMPLE III
Step one, a light source sends out an optical signal to enter a microdisk electro-optical modulator;
inputting PAM modulation data to a predistortion and FFE module;
thirdly, the driver drives the light intensity in the microdisk electro-optical modulator to change according to the predistortion and the output signal of the FFE module, so that the modulation of the optical signal is realized;
fourthly, the photodiode detects the light intensity change in the microdisk electro-optical modulator and converts the light intensity change into an electric signal which changes along with the PAM data;
fifthly, detecting the electric signal changing along with the PAM data by the eye pattern monitoring module, and obtaining eye pattern information;
step six, the self-adaptive nonlinear compensation algorithm module judges whether the PAM signal level is uniformly distributed or not according to the eye pattern information obtained by the eye pattern monitoring module, if not, the predistortion parameter is changed to enable the PAM signal level to tend to be uniform, and if so, the predistortion parameter is kept unchanged; the self-adaptive nonlinear compensation algorithm module judges whether the shapes or the areas of a plurality of sub-eye patterns of the PAM signal at the moment are the same and the largest according to the eye pattern information obtained by the eye pattern monitoring module, if the shapes or the areas of the sub-eye patterns are different, the FFE coefficient is changed to enable the shapes or the areas of the sub-eye patterns to be the same, if the shapes or the areas of the sub-eye patterns are the same but the sub-eye patterns are not the largest, the FFE coefficient is continuously changed to enable the shapes or the areas of the uniform sub-eye patterns to be the largest, and if the shapes or the areas of the uniform sub-eye patterns are the same and the largest, the FFE coefficient is kept unchanged;
and step seven, judging whether the distances among the adjacent eye pattern levels are equal and whether the shapes or the areas of the sub eye patterns are the same and the areas of the sub eye patterns are the largest, and repeating the step one to the step six if the distances are not equal.
Example four
Step one, a photodiode output multiplexer and a demultiplexer are switched to a first microdisk modulator in an N-path microdisk modulator array;
step two, the light source array sends out multiple paths of optical signals to enter the microdisk modulator array;
inputting the multi-path PAM modulation data to a predistortion and FFE module array;
fourthly, the driver array drives the light intensity in the microdisk electro-optical modulator array to change according to the predistortion and the multiple signals output by the FFE module array, so that the modulation of the multiple optical signals is realized;
fourthly, monitoring the light intensity change in the microdisk electro-optical modulator array by the photodiode array and converting the light intensity change into a plurality of paths of electric signals changing along with the PAM data;
sixthly, detecting the electric signal changing along with the PAM data by an eye pattern monitoring module, and obtaining eye pattern information;
step seven, the self-adaptive nonlinear compensation algorithm module judges whether the PAM signal level is uniformly distributed or not according to the eye pattern information obtained by the eye pattern monitoring module, if not, the predistortion parameter is changed to enable the PAM signal level to tend to be uniform, and if so, the predistortion parameter is kept unchanged; the self-adaptive nonlinear compensation algorithm module judges whether the shapes or the areas of a plurality of sub-eye patterns of the PAM signal at the moment are the same and the largest according to the eye pattern information obtained by the eye pattern monitoring module, if the shapes or the areas of the sub-eye patterns are different, the FFE coefficient is changed to enable the shapes or the areas of the sub-eye patterns to be the same, if the shapes or the areas of the sub-eye patterns are the same but the sub-eye patterns are not the largest, the FFE coefficient is continuously changed to enable the shapes or the areas of the uniform sub-eye patterns to be the largest, and if the shapes or the areas of the uniform sub-eye patterns are the same and the largest, the FFE coefficient is kept unchanged;
step eight, judging whether the distances among the adjacent eye pattern levels are equal and whether the shapes or the areas of the sub eye patterns are the same and the areas of the sub eye patterns are the largest, and if not, repeating the step two to the step seven;
and step nine, switching the photodiode output multiplexer and the demultiplexer to the next microdisk electro-optical modulator, and repeating the step two to the step eight until the last microdisk electro-optical modulator.
EXAMPLE five
Step one, sending an optical signal by a light source to enter a Mach-Zehnder electro-optic modulator;
inputting PAM modulation data to a predistortion and FFE module;
thirdly, the driver drives the light intensity in the Mach-Zehnder electro-optic modulator to change according to the predistortion and the output signal of the FFE module, so that the modulation of the optical signal is realized;
fourthly, the photodiode detects the light intensity change in the Mach-Zehnder electro-optic modulator and converts the light intensity change into an electrical signal changing along with PAM data;
fifthly, detecting the electric signal changing along with the PAM data by the eye pattern monitoring module, and obtaining eye pattern information;
step six, the self-adaptive nonlinear compensation algorithm module judges whether the PAM signal level is uniformly distributed or not according to the eye pattern information obtained by the eye pattern monitoring module, if not, the predistortion parameter is changed to enable the PAM signal level to tend to be uniform, and if so, the predistortion parameter is kept unchanged; the self-adaptive nonlinear compensation algorithm module judges whether the shapes or the areas of a plurality of sub-eye patterns of the PAM signal at the moment are the same and the largest according to the eye pattern information obtained by the eye pattern monitoring module, if the shapes or the areas of the sub-eye patterns are different, the FFE coefficient is changed to enable the shapes or the areas of the sub-eye patterns to be the same, if the shapes or the areas of the sub-eye patterns are the same but the sub-eye patterns are not the largest, the FFE coefficient is continuously changed to enable the shapes or the areas of the uniform sub-eye patterns to be the largest, and if the;
and step seven, judging whether the distances among the adjacent eye pattern levels are equal and whether the shapes or the areas of the sub eye patterns are the same and the areas of the sub eye patterns are the largest, and repeating the step one to the step six if the distances are not equal.
EXAMPLE six
Step one, a photodiode output multiplexer and a demultiplexer are switched to a first microdisk modulator in an N-path Mach-Zehnder modulator array;
step two, the light source array sends out multiple paths of optical signals to enter the Mach-Zehnder modulator array;
inputting the multi-path PAM modulation data to a predistortion and FFE module array;
fourthly, the driver array drives the light intensity in the Mach-Zehnder electro-optic modulator array to change according to the predistortion and the multiple signals output by the FFE module array, so that the modulation of the multiple optical signals is realized;
fourthly, detecting the light intensity change in the Mach-Zehnder electro-optic modulator array by the photodiode array and converting the light intensity change into a plurality of paths of electric signals changing along with the PAM data;
sixthly, monitoring the electric signal changed along with the PAM data by the eye pattern monitoring module, and obtaining eye pattern information;
step seven, the self-adaptive nonlinear compensation algorithm module judges whether the PAM signal level is uniformly distributed or not according to the eye pattern information obtained by the eye pattern monitoring module, if not, the predistortion parameter is changed to enable the PAM signal level to tend to be uniform, and if so, the predistortion parameter is kept unchanged; the self-adaptive nonlinear compensation algorithm module judges whether the shapes or the areas of a plurality of sub-eye patterns of the PAM signal at the moment are the same and the largest according to the eye pattern information obtained by the eye pattern monitoring module, if the shapes or the areas of the sub-eye patterns are different, the FFE coefficient is changed to enable the shapes or the areas of the sub-eye patterns to be the same, if the shapes or the areas of the sub-eye patterns are the same but the sub-eye patterns are not the largest, the FFE coefficient is continuously changed to enable the shapes or the areas of the uniform sub-eye patterns to be the largest, and if the shapes or the areas of the uniform sub-eye patterns are the same and the largest, the FFE coefficient is kept unchanged;
step eight, judging whether the distances among the adjacent eye pattern levels are equal and whether the shapes or the areas of the sub eye patterns are the same and the areas of the sub eye patterns are the largest, and if not, repeating the step two to the step seven;
and step nine, switching the photodiode output multiplexer and the demultiplexer to the next Mach-Zehnder electro-optic modulator, and repeating the step two to the step eight until the last microdisk electro-optic modulator.
It will be understood by those skilled in the art that the foregoing is only a preferred embodiment of the present invention, and is not intended to limit the invention, and that any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the scope of the present invention.
Claims (7)
1. An electro-optical modulator closed-loop nonlinear compensation system based on eye monitoring, the electro-optical modulator is driven by a driver to modulate output light of a light source and generate an optical signal which changes with a PAM signal, and an input signal of the driver is the PAM signal processed by a predistortion/FFE module, the system is characterized by comprising:
the monitoring module is used for detecting the intensity of the optical signal output by the electro-optical modulator in real time, converting the intensity of the optical signal into an electric signal and sending the electric signal to the eye pattern monitoring module;
the eye pattern monitoring module is used for converting the received electric signals into an eye pattern and sending the eye pattern to the self-adaptive nonlinear compensation module;
the adaptive nonlinear compensation module is used for judging whether the level of the current eye pattern is uniformly distributed, and if the level of the current eye pattern is not uniform, adaptively adjusting predistortion parameters in the predistortion/FFE module to enable the level of the eye pattern to tend to be uniform; and if the sub-eye patterns are uniform but not maximum, continuing to adaptively adjust the FFE coefficient in the predistortion/FFE module to enable the uniform sub-eye patterns to tend to be maximum.
2. An electro-optical modulator array closed-loop nonlinear compensation system based on eye pattern monitoring, the electro-optical modulator array comprises a plurality of electro-optical modulators, the electro-optical modulators correspond to a predistortion/FFE module and a driver one to one, the electro-optical modulators are driven by the corresponding drivers to modulate output light of a light source and generate optical signals changing along with PAM modulation data, and input signals of the drivers are PAM signals processed by the corresponding predistortion/FFE module, and the electro-optical modulator array closed-loop nonlinear compensation system is characterized by comprising:
the multiplexer is used for connecting the eye pattern monitoring module with all the monitoring modules and switching to different monitoring modules each time;
the demultiplexer is used for connecting the self-adaptive nonlinear compensation module and all the predistortion/FFE modules and switching to different predistortion/FFE modules each time;
the monitoring modules are in one-to-one correspondence with the electro-optical modulators and used for detecting the intensity of optical signals output by the corresponding electro-optical modulators in real time, converting the intensity of the optical signals into electric signals and sending the electric signals to the eye pattern monitoring modules;
the eye pattern monitoring module is used for converting the received electric signals into an eye pattern and sending the eye pattern to the self-adaptive nonlinear compensation module;
the adaptive nonlinear compensation module is used for judging whether the level of the current eye pattern is uniformly distributed, and if the level of the current eye pattern is not uniform, adaptively adjusting predistortion parameters in the predistortion/FFE module to enable the level of the eye pattern to tend to be uniform; and if the sub-eye patterns are uniform but not maximum, continuing to adaptively adjust the FFE coefficient in the predistortion/FFE module to enable the uniform sub-eye patterns to tend to be maximum.
3. The system of claim 1 or 2, wherein the eye monitor module is periodically turned on, and turned off after obtaining the optical PAM eye with uniform level distribution, uniform sub-eye distribution, and maximum after each turn on, and the adaptive non-linear compensation module keeps the output constant during the period from the turn off of the eye monitor module to the next turn on.
4. The system of claim 1 or 2, wherein when the error rate of the signal received by the receiving end exceeds a preset threshold, the eye pattern monitoring module is turned on, and is turned off after obtaining the optical PAM eye pattern with uniform level distribution, uniform sub-eye pattern distribution and maximum distribution after being turned on, and the adaptive nonlinear compensation module keeps the output unchanged during the period from turning off of the eye pattern monitoring module to turning on next time.
5. The system of claim 1 or 2, wherein the criterion for the uniformity of the PAM signal level distribution is: the distance between any adjacent eye levels is equal.
6. A system as claimed in claim 1 or 2, wherein the criterion for a uniform and maximal distribution of the sub-eye patterns of the eye pattern is: all sub-eye patterns are the same shape or area and largest.
7. The system of claim 1 or 2, wherein the electro-optic modulator is a ring modulator, a microdisk modulator, or a mach-zehnder modulator.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114362818A (en) * | 2021-12-20 | 2022-04-15 | 江苏科大亨芯半导体技术有限公司 | Method and system for measuring topping depth of topping signal by using main signal eye diagram |
| CN115913346A (en) * | 2022-11-30 | 2023-04-04 | 华中科技大学 | Monitoring method and system of optical eye pattern |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1795627A (en) * | 2003-04-03 | 2006-06-28 | 北方电讯网络有限公司 | Electrical domain compensation of non-linear effects in an optical communications system |
| CN109981500A (en) * | 2017-12-28 | 2019-07-05 | 海思光电子有限公司 | A kind of method and signal processing apparatus of signal processing |
| US20200145261A1 (en) * | 2017-08-07 | 2020-05-07 | Rambus Inc. | Receiver/transmitter co-calibration of voltage levels in pulse amplitude modulation links |
| US20200366536A1 (en) * | 2019-05-17 | 2020-11-19 | Electronics And Telecommunications Research Institute | Optical transmission apparatus and method for processing signal based on direct detection |
-
2021
- 2021-05-31 CN CN202110597724.9A patent/CN113267914B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1795627A (en) * | 2003-04-03 | 2006-06-28 | 北方电讯网络有限公司 | Electrical domain compensation of non-linear effects in an optical communications system |
| US20200145261A1 (en) * | 2017-08-07 | 2020-05-07 | Rambus Inc. | Receiver/transmitter co-calibration of voltage levels in pulse amplitude modulation links |
| CN109981500A (en) * | 2017-12-28 | 2019-07-05 | 海思光电子有限公司 | A kind of method and signal processing apparatus of signal processing |
| US20200366536A1 (en) * | 2019-05-17 | 2020-11-19 | Electronics And Telecommunications Research Institute | Optical transmission apparatus and method for processing signal based on direct detection |
Non-Patent Citations (1)
| Title |
|---|
| EMANUELE DEPAOLI 等: ""A 64 Gb/s Low-Power Transceiver for Short-Reach PAM-4 Electrical Links in 28nm FDSOI CMOS"", 《IEEE JOURNAL OF SOLID-STATE CIRCUITS》 * |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114362818A (en) * | 2021-12-20 | 2022-04-15 | 江苏科大亨芯半导体技术有限公司 | Method and system for measuring topping depth of topping signal by using main signal eye diagram |
| CN114362818B (en) * | 2021-12-20 | 2024-01-30 | 江苏科大亨芯半导体技术有限公司 | Method and system for measuring top-adjusting depth of top-adjusting signal by using main signal eye diagram |
| CN115913346A (en) * | 2022-11-30 | 2023-04-04 | 华中科技大学 | Monitoring method and system of optical eye pattern |
| CN115913346B (en) * | 2022-11-30 | 2024-04-19 | 华中科技大学 | Monitoring method and system for optical eye diagram |
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