CN114978320A - Optical fiber communication system performance optimization method and device based on directly modulated laser - Google Patents
Optical fiber communication system performance optimization method and device based on directly modulated laser Download PDFInfo
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
- H04B10/25—Arrangements specific to fibre transmission
- H04B10/2507—Arrangements specific to fibre transmission for the reduction or elimination of distortion or dispersion
- H04B10/2513—Arrangements specific to fibre transmission for the reduction or elimination of distortion or dispersion due to chromatic dispersion
- H04B10/2525—Arrangements specific to fibre transmission for the reduction or elimination of distortion or dispersion due to chromatic dispersion using dispersion-compensating fibres
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
- H04B10/50—Transmitters
- H04B10/501—Structural aspects
- H04B10/503—Laser transmitters
- H04B10/504—Laser transmitters using direct modulation
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L41/00—Arrangements for maintenance, administration or management of data switching networks, e.g. of packet switching networks
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Abstract
The invention discloses a performance optimization method of an optical fiber communication system based on a directly modulated laser, which comprises the following steps: substituting the initial relevant physical parameters into a system transmission function to calculate to obtain an initial system frequency response curve; adjusting the injection current I of a directly-tuned laser 0 Or the fiber dispersion D 0 The value makes the system frequency response curve as flat as possible; according to the injection current I of the directly modulated laser at the moment 0 Correcting the frequency response function of the directly modulated laser; according to the fiber dispersion D at that time 0 Correcting the transmission optical fiber; obtaining a new system frequency response curve according to the corrected parameters; and (4) carrying out electric domain frequency domain equalization at the transmitting end to obtain a precompensated system initial frequency response curve so as to optimize the performance of the system. The invention carries out primary compensation on the frequency response curve of the system transmission system and then utilizes the electric domain frequencyThe domain equalization technology further compensates the preliminarily compensated system frequency response curve, and the transmission performance of the system is improved. The invention also provides a corresponding optical fiber communication system performance optimization device based on the directly modulated laser.
Description
Technical Field
The invention belongs to the technical field of optical fiber communication, and particularly relates to a method and a device for optimizing the performance of an optical fiber communication system based on a directly modulated laser.
Background
In short-distance data communication systems and optical access network systems, low-cost and high-integration technologies have been the main research subjects. Direct-modulation and Direct-Detection (DML) technology based on a Direct Modulated Laser (DML) is widely researched and applied to an optical access network in recent years as a mainstream transmission technology of an optical short-distance and access network.
In a direct alignment detection system, compared with mach-zehnder modulators (MZMs) or electro-absorption modulated lasers (EMLs), DML has the advantages of high output optical power, low implementation cost, and small floor area, and is therefore more popular. However, the chirp impairment of DML is a big difficulty affecting its wide application, especially when the transmission distance is long and the speed is high. In the directly modulated laser, a modulation signal is used as a driving current of a gain region to complete electro-optical conversion, and the change of the current can also change the refractive index in an optical cavity, which can affect the wavelength excitation of the optical cavity, so that the optical frequency is changed, and the chirp phenomenon is generated. Chirp of a directly modulated laser can be divided into adiabatic chirp, for which the frequency of an output optical signal is related to the amplitude of an optical field, and transient chirp, for which the frequency of the output optical signal is related to the amplitude variation of the optical field. When signals are transmitted in an optical fiber, due to the existence of chromatic dispersion, signals with different optical frequencies have different group delays, so that aliasing with different frequencies is caused, and serious signal damage is caused. In order to improve the transmission performance, a chirp management technique is generally additionally adopted. There are mainly three schemes: optical spectrum filtering schemes, digital signal processing schemes and Complex Modulation schemes (Complex Modulation). The core idea of the optical spectrum filtering based scheme is to filter out the optical frequencies corresponding to the 0 symbol. When the 0 symbol is filtered out by the optical filter, the optical signal will only have 1 symbol left, which makes the optical signal not affected by the chromatic dispersion any more. In addition, when the decrease of the 0 symbol power also means the increase of the extinction ratio, the signal quality is further improved. Meanwhile, the optical filtering can be regarded as a Vestigial Sideband (VSB) signal to a certain extent, so that frequency response fading of a direct detection system can be avoided, and the method is suitable for long-distance transmission. However, the cost penalty of this solution comes from the extra added optical filter, which increases the cost to some extent, and on the other hand, in order to have better chirp filtering effect, the wavelength of the laser needs to be strictly aligned with the filter, which requires more precise feedback circuit correction, so the wavelength stability control also brings the cost penalty. The core idea of the digital signal processing-based scheme is to compensate nonlinear damage caused by chirp by using a nonlinear equalization technology. Since optical signals of different intensities correspond to different optical frequencies, the impairment caused by chirp is in fact a non-linear impairment, and current DSP-based solutions all utilize non-linear Volterra equalization techniques to compensate. The cost of this scheme comes mainly from two aspects, on one hand, the high-speed ADC is a relatively expensive chip, and on the other hand, the Volterra filter requires second and third order taps, which requires a large number of multiplication operations, resulting in a large increase in cost and power consumption. The core idea of a Complex modulation (Complex modulation) scheme is that phase change caused by chirp is taken as one modulation dimension, and two-dimensional modulation of a coherent system can be realized to a certain extent.
In summary, the three schemes bring a large cost, the cost of optical filtering is the extra optical filter and the corresponding wavelength control, the cost of Volterra digital signal processing is the complex second-order and third-order multiplication circuit, and the cost of complex modulation is the complexity of coherent reception. Because of these cost penalties, it is important to find a lower cost solution to suppress the damage caused by chirp.
Disclosure of Invention
The invention provides a method for optimizing the performance of an optical fiber communication system based on a directly modulated laser, which aims to overcome the defects in the prior art, and can apply the directly modulated laser to short-distance data communication and access network systems and metropolitan area networks with transmission distances larger than 20 kilometers.
To achieve the above object, according to an aspect of the present invention, there is provided a method for optimizing performance of an optical fiber communication system based on a directly modulated laser, including the steps of:
s1: extracting initial relevant physical parameters of an optical fiber communication system based on a directly modulated laser, wherein the optical fiber communication system comprises the directly modulated laser at an emission end and transmission optical fibers with different dispersion values;
s2: performing mathematical modeling on an optical fiber communication system based on a directly modulated laser, establishing a system transmitting and transmitting frequency response function model except for a receiving end, and substituting the obtained initial relevant physical parameters into the frequency response function model to calculate to obtain a system initial frequency response curve except for the receiving end;
s3: pre-compensating the initial frequency response curve of the system, namely adjusting the injection current of the direct modulation laser, wherein the adjusted injection current is required to be in a linear region of the driving current of the direct modulation laser and meets the requirement of the extinction ratio of a device;
s4: pre-compensating the initial frequency response curve of the system, namely adjusting the dispersion value of the optical fiber to enable the total system frequency response curve of the system to meet the preset flat requirement and achieve the distortion-free transmission condition;
s5: modifying the directly modulated laser according to the injection current of the new directly modulated laser obtained in the step S3 to change the injection current value of the new directly modulated laser; performing dispersion compensation processing on the transmission fiber according to the new fiber dispersion value obtained in the step S4;
s6: substituting the corrected parameters into the total amplitude response of the system according to the step S5 to obtain an updated system frequency response curve;
s7: and (4) aiming at the updated system frequency response curve obtained in the step (S6), optimizing by using an electric domain frequency domain equalization technology to further flatten the system frequency response curve and enable the total transmission characteristic of the system to reach a distortion-free transmission condition.
In step S1, one embodiment of the present invention obtains the following physical parameters of the directly modulated laser and the transmission fiber at the transmitting end of the system by pre-designing the system or measuring the actual system.
In one embodiment of the invention, the physical parameters include: linewidth enhancement factor alpha of directly modulated laser 0 Adiabatic chirp parameter kappa for directly modulated lasers 0 Injection current I of directly modulated laser 0 Optical fiber dispersion D 0 And the length L of the optical fiber 0 。
In one embodiment of the present invention, the mathematical model established in step S2 is:
in a transmission system based on a directly modulated laser, considering injection current and fiber dispersion factors of the directly modulated laser, frequency response is expressed by the following formula:
in this formula, the first term on the right is the frequency response caused by transient chirp, which is denoted as H tst (f, L), the second term is the frequency response due to adiabatic chirp, denoted as H adb (f, L), where f represents frequency, L represents transmission distance, I represents injection current, alpha represents line width enhancement factor, D represents fiber dispersion, lambda represents wavelength of the directly tuned laser, c represents speed of light in vacuum, epsilon represents gain limiting factor, gamma represents light limiting factor, I th Represents the threshold current, e represents the electron charge, and V represents the active region volume;
the overall amplitude response of the system is a superposition of two frequency responses, namely:
and substituting the initial relevant physical parameters obtained in the step S1 into the overall amplitude response formula of the system to obtain the initial frequency response curve of the system.
In one embodiment of the present invention, the system frequency response curve pre-compensation method is completed by adjusting the physical parameters of the injection current and the optical fiber dispersion value of the directly modulated laser.
In an embodiment of the present invention, the system frequency response curve pre-compensation is divided into two cases:
(1) when the dispersion value of the optical fiber can be changed, namely the optical fiber can be replaced, the dispersion values of different existing optical fibers are measured and recorded as D i ，i＝1,2,…,n；
(2) When the dispersion value of the optical fiber cannot be changed, namely the optical fiber cannot be changed, recording the current dispersion value of the optical fiber as D 0 ；
For different dispersion values D i Substituting the amplitude response equation into the total amplitude response equation of the system, and adjusting different injection current values I through simulation i And obtaining a series of system frequency response curves under different conditions, and finding out a flat system frequency response curve under a limited condition. And recording the dispersion value and the injection current value of the directly modulated laser at the moment, and correspondingly modifying the physical parameters of the system.
In an embodiment of the present invention, the method for compensating a system frequency response curve by using a frequency domain equalization technology is implemented by using a digital signal processing technology, and the specific method is as follows:
carrying out Fourier transform on original data X of a transmitting end to obtain X;
performing Fourier transform on the data Y received by the receiving end to obtain Y;
thirdly, obtaining a system frequency response curve from the transformed data Y/X;
fourthly, smoothing the system frequency response curve;
obtaining new data after negating the system frequency response curve;
and sixthly, multiplying the original data and the constructed new data in the frequency domain, and then converting the multiplied original data back to the time domain for sending.
In one embodiment of the invention, factors that affect system performance include: the injection current of the directly modulated laser, the dispersion of the optical fiber and a digital signal processing algorithm.
In an embodiment of the present invention, in the step S4, the total system frequency response curve of the system is made as flat as possible, specifically: so that the difference in amplitude between the low frequency part and the high frequency part of the system frequency response curve is less than 5 dBm.
According to another aspect of the present invention, there is also provided a performance optimization apparatus for an optical fiber communication system based on a directly modulated laser, comprising: the optical fiber communication system performance optimization method based on the direct-tuned laser comprises at least one processor and a memory, wherein the at least one processor and the memory are connected through a data bus, and the memory stores instructions capable of being executed by the at least one processor, and the instructions are used for completing the performance optimization method of the optical fiber communication system based on the direct-tuned laser after being executed by the processor.
Generally, compared with the prior art, the technical scheme of the invention has the following beneficial effects:
the invention finds the physical parameters influencing the transmission performance of the communication system based on the direct-tuned laser by carrying out physical modeling on the communication system based on the direct-tuned laser, further improves the performance of the system by combining the physical layer optimization of the device and the optical fiber link and the digital layer optimization of the digital signal processing algorithm, and simultaneously reduces the pressure of frequency domain equalization by carrying out the frequency response curve pre-compensation of the system, so that the complexity of the digital signal processing algorithm is reduced, and the cost of the system is further reduced.
Drawings
FIG. 1 is a schematic flow chart of the method for optimizing the performance of an optical fiber communication system based on a directly modulated laser according to the present invention;
FIG. 2 is a schematic diagram of a system frequency response curve under an initial condition of the system in the embodiment of the present invention;
FIG. 3 is a schematic diagram of a system frequency response curve after a system updates parameters according to an embodiment of the present invention;
FIG. 4 is a flow chart of the frequency domain equalization algorithm in an embodiment of the present invention;
FIG. 5 is a schematic diagram illustrating a principle of compensating a frequency response curve of a system by using a frequency domain equalization technique according to an embodiment of the present invention;
fig. 6 is a diagram illustrating the result of compensating the system frequency response curve by using the frequency domain equalization technique in the embodiment of the present invention.
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.
Factors that affect system performance include: injection current of the directly modulated laser, dispersion of the optical fiber and a digital signal processing algorithm.
As shown in fig. 1, the present invention provides a method for optimizing the performance of an optical fiber communication system based on a directly modulated laser, which comprises the following steps:
s1: initial relevant physical parameters of a directly modulated laser based optical fiber communication system are extracted, wherein the optical fiber communication system comprises a directly modulated laser at a transmitting end and transmission optical fibers with different dispersion values. The following physical parameters of the directly modulated laser and the transmission optical fiber at the transmitting end of the system can be obtained through system pre-design or measurement of an actual system, and include: linewidth enhancement factor alpha of directly modulated laser 0 Adiabatic chirp parameter kappa for directly modulated lasers 0 Injection current I of directly modulated laser 0 Optical fiber dispersion D 0 And the length L of the optical fiber 0 And the like;
s2: performing mathematical modeling on the optical fiber communication system based on the directly modulated laser, establishing a system transmitting and transmitting frequency response function model except for a receiving end, substituting the obtained initial relevant physical parameters into the frequency response function model, and calculating to obtain a system initial frequency response curve except for the receiving end, wherein the mathematical model established in the step S2 is as follows:
in a transmission system based on a directly modulated laser, considering injection current and fiber dispersion factors of the directly modulated laser, frequency response is expressed by the following formula:
in this formula, the first term on the right is the frequency response caused by transient chirp, which is denoted as H tst (f, L), the second term is the frequency response due to adiabatic chirp, which is denoted as H adb (f, L), where f represents frequency, L represents transmission distance, I represents injection current, alpha represents line width enhancement factor, D represents fiber dispersion, lambda represents wavelength of the directly tuned laser, c represents speed of light in vacuum, epsilon represents gain limiting factor, gamma represents light limiting factor, I th Representing the threshold current, e the electron charge, and V the active region volume. The total amplitude response of the system is the superposition of two frequency responses, and the formula of the total amplitude response of the system is as follows:
the initial correlation physical parameters obtained in step S1 are substituted into the above-mentioned overall magnitude response formula of the system to obtain the initial frequency response curve of the system as shown in fig. 2.
S3: and pre-compensating the initial frequency response curve of the system, namely adjusting the injection current of the directly modulated laser, wherein the adjusted injection current is required to be in a linear region of the driving current of the directly modulated laser, and the requirement of the extinction ratio of a device is met.
S4: the initial frequency response curve of the system is pre-compensated, that is, the dispersion value of the optical fiber is adjusted to make the total system frequency response curve of the system meet the preset flat requirement, so as to achieve the distortion-free transmission condition (specifically, the amplitude difference value between the low frequency part and the high frequency part of the system frequency response curve is less than 0dBm, and is close to 0dBm as much as possible, or even equal to 0 dBm).
The system frequency response curve precompensation method is completed by adjusting physical parameters of injection current and optical fiber dispersion value of a direct-tuned laser, and is divided into two conditions:
(1) when the dispersion value of the optical fiber can be changed, namely the optical fiber can be replaced, the dispersion values of different existing optical fibers are measured and recorded as D i ，i＝1,2,…,n；
(2) When the dispersion value of the optical fiber cannot be changed, namely the optical fiber cannot be changed, recording the current dispersion value of the optical fiber as D 0 ；
For different dispersion values D i Substituting the amplitude response equation into the total system amplitude response equation, and regulating different injection current values I through simulation i And obtaining a series of system frequency response curves under different conditions, and finding out a flat system frequency response curve under a limited condition. And recording the dispersion value and the injection current value of the directly modulated laser at the moment, and correspondingly modifying the physical parameters of the system.
S5: modifying the directly modulated laser according to the injection current of the new directly modulated laser obtained in the step S3 to change the injection current value of the new directly modulated laser; the dispersion compensation process is performed on the transmission fiber according to the new fiber dispersion value obtained in step S4.
S6: and substituting the corrected parameters into the total amplitude response of the system according to the step S5 to obtain an updated system frequency response curve as shown in FIG. 3.
S7: and (4) aiming at the updated system frequency response curve obtained in the step (S6), optimizing by using an electric domain frequency domain equalization technology to further flatten the system frequency response curve and enable the total transmission characteristic of the system to reach a distortion-free transmission condition.
The method for compensating the system frequency response curve by using the frequency domain equalization technology is realized by using a digital signal processing technology, and as shown in fig. 4, the specific method comprises the following steps:
carrying out Fourier transform on original data X of a transmitting end to obtain X;
performing Fourier transform on the data Y received by the receiving end to obtain Y;
thirdly, obtaining a system frequency response curve from the transformed data Y/X;
fourthly, smoothing the system frequency response curve;
obtaining new data after negating the system frequency response curve;
and sixthly, multiplying the originating data and the constructed new data in the frequency domain, and then converting the multiplied data back to the time domain for sending.
After the system frequency response curve is pre-compensated, the system frequency response curve is further compensated by utilizing a digital signal processing algorithm frequency domain equalization technology. Fig. 5 is a schematic diagram illustrating the principle of compensating the frequency response curve of the system by using the frequency domain equalization technique. Fig. 6 shows the result of compensating the system frequency response curve by using the frequency domain equalization technique. The optimization scheme shown in fig. 6 is better than the optimization of the physical parameters of the device or the use of the digital signal processing algorithm, and the system performance is improved greatly.
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 (10)
1. A performance optimization method of an optical fiber communication system based on a directly modulated laser is characterized by comprising the following steps:
s1: extracting initial relevant physical parameters of an optical fiber communication system based on a directly modulated laser, wherein the optical fiber communication system comprises the directly modulated laser at an emission end and transmission optical fibers with different dispersion values;
s2: performing mathematical modeling on an optical fiber communication system based on a directly modulated laser, establishing a system transmitting and transmitting frequency response function model except for a receiving end, and substituting the obtained initial relevant physical parameters into the frequency response function model to calculate to obtain a system initial frequency response curve except for the receiving end;
s3: pre-compensating the initial frequency response curve of the system, namely adjusting the injection current of the directly modulated laser, wherein the adjusted injection current is required to be in a linear region of the driving current of the directly modulated laser and meet the requirement of the extinction ratio of a device;
s4: pre-compensating the initial frequency response curve of the system, namely adjusting the dispersion value of the optical fiber to enable the total system frequency response curve of the system to meet the preset flat requirement and achieve the distortion-free transmission condition;
s5: modifying the directly modulated laser according to the injection current of the new directly modulated laser obtained in the step S3 to change the injection current value of the new directly modulated laser; performing dispersion compensation processing on the transmission fiber according to the new fiber dispersion value obtained in the step S4;
s6: substituting the corrected parameters into the total amplitude response of the system according to the step S5 to obtain an updated system frequency response curve;
s7: and (4) aiming at the updated system frequency response curve obtained in the step (S6), optimizing by using an electric domain frequency domain equalization technology to further flatten the system frequency response curve and enable the total transmission characteristic of the system to reach a distortion-free transmission condition.
2. The method for optimizing the performance of an optical fiber communication system based on a directly tuned laser as claimed in claim 1, wherein in step S1, the following physical parameters of the directly tuned laser at the transmitting end of the system and the transmission fiber are obtained by pre-designing the system or measuring the actual system.
3. A method for performance optimization of a fibre optic communication system based on a directly tuned laser as claimed in claim 1 or 2, wherein said physical parameters comprise: linewidth enhancement factor alpha of directly modulated laser 0 Adiabatic chirp parameter kappa for directly modulated lasers 0 Injection current I of directly modulated laser 0 Optical fiber dispersion D 0 And the length L of the optical fiber 0 。
4. The method for optimizing the performance of the fiber-optic communication system based on the directly modulated laser as claimed in claim 1 or 2, wherein the mathematical model established in step S2 is:
in a transmission system based on a directly modulated laser, considering injection current and fiber dispersion factors of the directly modulated laser, frequency response is expressed by the following formula:
in this equation, the first term on the right is the frequency response due to transient chirp, which is denoted as H tst (f, L), the second term being adiabatic chirpThe induced frequency response, denoted as H adb (f, L), where f represents frequency, L represents transmission distance, I represents injection current, alpha represents line width enhancement factor, D represents fiber dispersion, lambda represents wavelength of the directly tuned laser, c represents speed of light in vacuum, epsilon represents gain limiting factor, gamma represents light limiting factor, I th Represents the threshold current, e represents the electron charge, and V represents the active region volume;
the overall amplitude response of the system is a superposition of two frequency responses, namely:
and substituting the initial relevant physical parameters obtained in the step S1 into the overall amplitude response formula of the system to obtain the initial frequency response curve of the system.
5. The method for optimizing the performance of an optical fiber communication system based on a directly tuned laser as claimed in claim 1 or 2, wherein the method for pre-compensating the system frequency response curve is performed by adjusting the physical parameters of the injection current and the optical fiber dispersion value of the directly tuned laser.
6. The method as claimed in claim 5, wherein the pre-compensation of the system frequency response curve is divided into two cases:
(1) when the dispersion value of the optical fiber can be changed, namely the optical fiber can be replaced, the dispersion values of different existing optical fibers are measured and recorded as D i ，i＝1,2,…,n；
(2) When the dispersion value of the optical fiber cannot be changed, namely the optical fiber cannot be changed, recording the current dispersion value of the optical fiber as D 0 ；
For different dispersion values D i Substituting the amplitude response equation into the total amplitude response equation of the system, and adjusting different injection current values I through simulation i And obtaining a series of system frequency response curves under different conditions, and finding out a flat system frequency response curve under a limited condition. Record the color at that timeAnd correspondingly modifying the physical parameters of the system by the dispersion value and the injection current value of the directly modulated laser.
7. The method for optimizing the performance of the fiber-optic communication system based on the directly modulated laser according to claim 1 or 2, wherein the method for compensating the system frequency response curve by using the frequency domain equalization technology is realized by using a digital signal processing technology, and the specific method is as follows:
carrying out Fourier transform on original data X of a transmitting end to obtain X;
performing Fourier transform on the data Y received by the receiving end to obtain Y;
thirdly, obtaining a system frequency response curve from the transformed data Y/X;
fourthly, smoothing the system frequency response curve;
obtaining new data after negating the system frequency response curve;
and sixthly, multiplying the originating data and the constructed new data in the frequency domain, and then converting the multiplied data back to the time domain for sending.
8. A method as claimed in claim 1 or 2, wherein the factors affecting the performance of the system include: injection current of the directly modulated laser, dispersion of the optical fiber and a digital signal processing algorithm.
9. The method for optimizing performance of an optical fiber communication system based on a directly tuned laser according to claim 1 or 2, wherein in the step S4, the total system frequency response curve of the system is made as flat as possible, specifically: so that the difference in amplitude between the low frequency part and the high frequency part of the system frequency response curve is less than 5 dBm.
10. The utility model provides an optical fiber communication system performance optimization device based on directly transferred laser ware which characterized in that:
the optical fiber communication system performance optimization method based on the direct tuned laser comprises at least one processor and a memory, wherein the at least one processor and the memory are connected through a data bus, and the memory stores instructions which can be executed by the at least one processor, and the instructions are used for completing the performance optimization method of the optical fiber communication system based on the direct tuned laser according to any one of claims 1 to 9 after being executed by the processor.
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| CN106130644A (en) * | 2016-07-20 | 2016-11-16 | 上海交通大学 | Frequency-domain equilibrium method based on dispersion overcompensation |
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| CN102420661A (en) * | 2011-12-15 | 2012-04-18 | 华中科技大学 | Device for compensating non-linear damage of optical fiber |
| US20150333837A1 (en) * | 2014-05-13 | 2015-11-19 | Infinera Corporation | Tracking nonlinear cross-phase modulation noise and linewidth induced jitter in coherent optical fiber communication links |
| CN106130644A (en) * | 2016-07-20 | 2016-11-16 | 上海交通大学 | Frequency-domain equilibrium method based on dispersion overcompensation |
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