WO2015078191A1 - 一种消除非线性效应的方法、发射机及接收机 - Google Patents

一种消除非线性效应的方法、发射机及接收机 Download PDF

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Publication number
WO2015078191A1
WO2015078191A1 PCT/CN2014/082957 CN2014082957W WO2015078191A1 WO 2015078191 A1 WO2015078191 A1 WO 2015078191A1 CN 2014082957 W CN2014082957 W CN 2014082957W WO 2015078191 A1 WO2015078191 A1 WO 2015078191A1
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Prior art keywords
signal
transmitted
compensation
redundant
dispersion
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PCT/CN2014/082957
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English (en)
French (fr)
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沈百林
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中兴通讯股份有限公司
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Priority to EP14865284.5A priority Critical patent/EP3076568B1/en
Priority to US15/039,503 priority patent/US9973279B2/en
Publication of WO2015078191A1 publication Critical patent/WO2015078191A1/zh

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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
    • H04B10/58—Compensation for non-linear transmitter output
    • 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
    • H04B10/25137—Arrangements specific to fibre transmission for the reduction or elimination of distortion or dispersion due to chromatic dispersion using pulse shaping at the transmitter, e.g. pre-chirping or dispersion supported transmission [DST]
    • 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
    • H04B10/2543—Arrangements specific to fibre transmission for the reduction or elimination of distortion or dispersion due to fibre non-linearities, e.g. Kerr effect
    • 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
    • H04B10/60—Receivers
    • H04B10/66—Non-coherent receivers, e.g. using direct detection
    • H04B10/69—Electrical arrangements in the receiver
    • H04B10/697—Arrangements for reducing noise and distortion
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B2210/00—Indexing scheme relating to optical transmission systems
    • H04B2210/25—Distortion or dispersion compensation
    • H04B2210/254—Distortion or dispersion compensation before the transmission line, i.e. pre-compensation

Definitions

  • the present invention relates to optical communication technologies, and more particularly to a method, a transmitter and a receiver for eliminating nonlinear effects. Background technique
  • optical transmission The limiting factors of optical transmission are attenuation, noise, dispersion, polarization mode dispersion, nonlinear effects, and the like.
  • the compensation or elimination technique of nonlinear effects has been a hot research topic.
  • the relatively practical methods include the receiver digital reverse transmission method and the transmission side perturbation predistortion method.
  • the digital reverse transmission method requires multiple dispersion compensation and nonlinear phase compensation in multiple times.
  • the higher the number of times the larger the power consumption, the chip is difficult to bear, and the phase adjustment factor in nonlinear phase compensation needs to be optimized for search, which is difficult to implement;
  • the perturbation predistortion requires system configuration related information to the transmitter, especially the perturbation coefficient calculation involves exponential integral functions of real and imaginary numbers, and the longer the system transmission distance, the more perturbation terms involved, the more difficult it is to operate. Big.
  • embodiments of the present invention provide a method, a transmitter, and a receiver for eliminating nonlinear effects.
  • a method for eliminating nonlinear effects provided by an embodiment of the present invention is applied to a transmitter, including:
  • the compensation amount of the dispersion pre-compensation performed on the signal to be transmitted and the redundant signal is half of the total amount of dispersion of the system.
  • the performing the dispersion pre-compensation on the to-be-transmitted signal and the redundant signal respectively includes:
  • Dispersion pre-compensation is performed on the to-be-transmitted signal and the redundant signal, respectively, using time domain dispersion compensation or frequency domain dispersion compensation.
  • An embodiment of the present invention further provides a method for eliminating a nonlinear effect, which is applied to a receiver, including:
  • the signal to be transmitted eliminates nonlinear effects
  • the receiver is a coherent receiver.
  • the embodiment of the invention further provides a transmitter, comprising: a setting unit, a dispersion compensation unit and a modulation unit, wherein:
  • the setting unit is configured to set a signal to be transmitted and a redundant signal, where the redundant signal is a Y-axis symmetric signal of the signal to be transmitted;
  • the dispersion compensation unit is configured to perform dispersion pre-compensation on the to-be-transmitted signal and the redundant signal respectively after the setting unit completes setting;
  • the modulating unit is configured to perform signal modulation after the dispersion compensation unit completes dispersion pre-compensation.
  • the dispersion compensation unit performs the signal to be transmitted and the redundant signal.
  • the compensation amount of the dispersion pre-compensation is half of the total dispersion amount of the system.
  • the dispersion compensation unit respectively performs dispersion pre-compensation on the to-be-transmitted signal and the redundant signal, and includes:
  • Dispersion pre-compensation is performed on the to-be-transmitted signal and the redundant signal, respectively, using time domain dispersion compensation or frequency domain dispersion compensation.
  • An embodiment of the present invention further provides a receiver, including: a receiving unit, a data recovery unit, a nonlinear effect removing unit, and a data determining unit, where:
  • the receiving unit is configured to receive a signal
  • the data recovery unit is configured to perform data recovery to obtain a signal to be transmitted and a redundant signal, where the redundant signal is a Y-axis symmetric signal of the signal to be transmitted;
  • the non-linear effect eliminating unit is configured to perform data decision respectively after the data recovery unit obtains the to-be-transmitted signal and the redundant signal, and align the redundant signal with the signal to be transmitted, and subtract the signal to be transmitted. Aligning the conjugate signal of the redundant signal to eliminate a nonlinear effect on the signal to be transmitted;
  • the data decision unit is configured to perform data decision on a signal to be transmitted that eliminates non-linear effects.
  • the receiver is a coherent receiver.
  • Embodiments of the present invention also provide a computer readable storage medium comprising a set of computer executable instructions for performing a method of canceling a nonlinear effect on a transmitter side.
  • Embodiments of the present invention also provide a computer readable storage medium comprising a set of computer executable instructions for performing a method of canceling a nonlinear effect on a receiver side.
  • the embodiment of the present invention is simpler to implement than other existing nonlinear compensation methods, and the performance is more excellent.
  • FIG. 1 is a flow chart of a transmitter side of a method for eliminating nonlinear effects according to an embodiment of the present invention
  • 2 is a flowchart of a receiver side of a method for eliminating a nonlinear effect according to an embodiment of the present invention
  • FIG. 3 is a structural diagram of an optical communication system according to an embodiment of the present invention
  • FIG. 4 is a flow chart including a transmitter side and a receiver side of a method for eliminating a nonlinear effect according to an embodiment of the present invention
  • FIG. 8 is a structural diagram of a transmitter according to an embodiment of the present invention.
  • FIG. 9 is a structural diagram of a receiver according to an embodiment of the present invention. detailed description
  • the method for eliminating nonlinear effects in the embodiment of the present invention is on the transmitter side, and includes:
  • Step 101 Set a signal to be transmitted and a redundant signal, and the redundant signal is a Y-axis symmetric signal of the signal to be transmitted;
  • the signal modulation pattern is not limited.
  • Step 102 Perform dispersion pre-compensation on the transmission signal and the redundant signal respectively;
  • the dispersion pre-compensation is performed on the polarization X and Y signals, respectively, and the compensation amount is half of the total dispersion of the system.
  • the dispersion compensation method may be time domain dispersion compensation or frequency domain dispersion compensation.
  • Step 103 Perform signal modulation after the dispersion pre-compensation is completed.
  • the dispersion pre-compensated signal is subjected to polarization multiplexing modulation.
  • the signal modulation is the same as that of the conventional optical communication system, that is, the polarization X and Y data respectively perform signal modulation, and are implemented by a digital-to-analog converter (DAC), and then polarization-multiplexed.
  • DAC digital-to-analog converter
  • the method for eliminating nonlinear effects in the embodiment of the present invention is on the receiver side, and includes:
  • Step 201 Receive a signal and perform data recovery to obtain a signal to be transmitted and a redundant signal, where the redundant signal is a Y-axis symmetric signal of the signal to be transmitted;
  • the polarization state signals Ex(t) and Ey(t) are recovered according to the conventional coherent reception algorithm, wherein the dispersion compensation amount is half of the total dispersion amount of the system.
  • Step 202 After obtaining the signal to be transmitted and the redundant signal, respectively performing data decision, aligning the redundant signal with the signal to be transmitted, subtracting the conjugate signal of the aligned redundant signal from the signal to be transmitted, and implementing the signal to be transmitted Signal cancellation nonlinear effects;
  • Step 203 Perform data re-judgment on the signal to be transmitted that eliminates the nonlinear effect.
  • the optical communication system of the embodiment of the present invention includes a transmitter 10, a receiver 20, and a fiber optic system 30, wherein the transmitter 10 implements signal redundancy processing, pre-compensation system half-dispersion, and completes polarization multiplexing modulation;
  • the receiver 20 is a coherent receiver, and the receiver 20 implements signal recovery, performs nonlinear decorrelation processing on the signals of the two polarization states to achieve the elimination of nonlinear effects, and finally determines the signal for eliminating the nonlinear effect.
  • Fiber optic system 30 includes, but is not limited to, multiple fibers 31 and the optical amplifier 32, for example, may also include a common multiplexer wave device of a wavelength division multiplexing system or the like, that is, it is applicable to an existing optical communication system.
  • the transmitting end sets the redundant signal Ey, which is the Y-axis symmetric signal of Ex. It can be proved by the principle of Volterra series theory. In the transmission process, Ex and Ey have correlation, and can be considered as Ex and conj(Ey). The nonlinear distortion is exactly the same, so subtracting the two at the receiving end eliminates the nonlinear effect.
  • Ey the redundant signal of Ex. It can be proved by the principle of Volterra series theory. In the transmission process, Ex and Ey have correlation, and can be considered as Ex and conj(Ey). The nonlinear distortion is exactly the same, so subtracting the two at the receiving end eliminates the nonlinear effect.
  • a transmitter side and a receiver side including:
  • Step 401 Set a signal to be transmitted and a redundant signal, where the redundant signal is a Y-axis symmetric signal of the signal to be transmitted;
  • the signal modulation pattern is not limited.
  • Step 402 Perform dispersion pre-compensation on the transmission signal and the redundant signal respectively;
  • the dispersion pre-compensation is performed on the polarization X and Y signals, respectively, and the compensation amount is half of the total dispersion of the system.
  • the dispersion compensation method may be time domain dispersion compensation or frequency domain dispersion compensation.
  • Step 403 Perform signal modulation after completing dispersion pre-compensation
  • the dispersion pre-compensated signal is subjected to polarization multiplexing modulation.
  • the signal modulation is the same as that of the conventional optical communication system, that is, the polarization X and Y data are respectively subjected to signal modulation, implemented by a digital-to-analog converter (DAC), and then polarization-multiplexed.
  • DAC digital-to-analog converter
  • Step 404 Receive a signal and perform data recovery to obtain a signal to be transmitted and a redundant signal, where the redundant signal is a Y-axis symmetric signal of the signal to be transmitted;
  • the polarization state signals Ex(t) and Ey(t) are recovered according to the conventional coherent reception algorithm, wherein the dispersion compensation amount is half of the total dispersion amount of the system.
  • This step is a mature technology of the existing optical communication system. After this step, the X and Y polarization states are obtained: Ex(t) and Ey(t) 0
  • Step 405 After obtaining the signal to be transmitted and the redundant signal, respectively performing data decision, aligning the redundant signal with the signal to be transmitted, subtracting the conjugate signal of the aligned redundant signal from the signal to be transmitted, and implementing the signal to be transmitted Signal cancellation nonlinear effects;
  • Step 406 Perform data re-judgment on the signal to be transmitted that eliminates the nonlinear effect.
  • the Es is subjected to data decision.
  • Data decision is a mature technology of existing optical communication systems.
  • 5 to 7 are examples of simulation results for eliminating nonlinear effects by using an embodiment of the present invention.
  • the modulation pattern is PDM-QPSK (polarization multiplexing-quadrature modulation), and the symbol rate of a single polarization signal is 10 Gbd, G.652 fiber system.
  • Figure 5 is a constellation diagram of the X-polarization signal
  • Figure 6 is a constellation diagram of the Y-polarization signal
  • Figure 7 is an Ex-conj(Ey) constellation diagram, where conj represents the conjugate, and real represents the real part of the complex signal.
  • imag represents the imaginary part of the complex signal.
  • an embodiment of the present invention further provides a transmitter, including: a setting unit 11, a dispersion compensation unit 12, and a modulation unit 13, wherein:
  • the setting unit 11 is configured to set a signal to be transmitted and a redundant signal, and the redundant signal is to be transmitted Y-axis symmetric signal of the signal;
  • the dispersion compensation unit 12 is configured to perform dispersion pre-compensation on the transmission signal and the redundant signal respectively after the setting unit completes the setting;
  • the modulating unit 13 is configured to perform signal modulation after the dispersion compensation unit completes dispersion pre-compensation.
  • the dispersion compensation unit 12 compensates for the dispersion precompensation performed on the transmitted signal and the redundant signal by half the total amount of dispersion of the system.
  • the dispersion compensation unit 12 performs dispersion pre-compensation on the transmission signal and the redundant signal, respectively, including: performing dispersion pre-compensation on the transmission signal and the redundant signal, respectively, using time domain dispersion compensation or frequency domain dispersion compensation.
  • an embodiment of the present invention further provides a receiver, including: a receiving unit 21, a data recovery unit 22, a nonlinear effect removing unit 23, and a data determining unit 24, wherein: the receiving unit 21 is configured to receive Signal
  • the data recovery unit 22 is configured to perform data recovery, obtain a signal to be transmitted and a redundant signal, and the redundant signal is a Y-axis symmetric signal of the signal to be transmitted;
  • the nonlinear effect removing unit 23 is configured to perform data decision respectively after the data recovery unit obtains the signal to be transmitted and the redundant signal, and align the redundant signal with the signal to be transmitted, and subtract the aligned redundancy from the signal to be transmitted.
  • the conjugate signal of the signal to achieve a nonlinear effect on the signal to be transmitted;
  • the data decision unit 24 is configured to perform data determination on the signal to be transmitted that eliminates non-linear effects.
  • the receiver of the embodiment of the present invention may be a coherent receiver.
  • the receiving unit 21 may be implemented by a communication function chip of the receiver
  • the data recovery unit 22, the nonlinear effect removing unit 23, and the data determining unit 24 may be implemented by a CPU, an MPU, a DSP or an FPGA of the receiver.
  • Embodiments of the present invention also provide a computer readable storage medium comprising a set of computer executable instructions for performing a method of canceling a nonlinear effect on a transmitter side.
  • Embodiments of the present invention also provide a computer readable storage medium comprising a set of computer executable instructions for performing a method of canceling a nonlinear effect on a receiver side.
  • a general-purpose computing device which can be centralized on a single computing device or distributed over a network of multiple computing devices.
  • they may be implemented by program code executable by the computing device such that they may be stored in the storage device by the computing device and, in some cases, may be executed in a different order than herein.
  • the steps shown or described are either made separately into individual integrated circuit modules, or a plurality of modules or steps are fabricated as a single integrated circuit module.
  • the invention is not limited to any particular combination of hardware and software.

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  • Electromagnetism (AREA)
  • Engineering & Computer Science (AREA)
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Abstract

本发明公开了一种消除非线性效应的方法、发射机及接收机，包括：设置待传输信号和冗余信号，所述冗余信号为所述待传输信号的Y轴对称信号；在完成设置后，分别对所述待传输信号和冗余信号执行色散预补偿，并在完成色散预补偿后执行信号调制。

Description

一种消除非线性效应的方法、 发射机及接收机 技术领域
本发明涉及光通信技术， 尤其涉及一种消除非线性效应的方法、 发射 机及接收机。 背景技术
光传输的受限因素有衰减、 噪声、 色散、 偏振模色散、 非线性效应等。 非线性效应的补偿或消除技术一直是研究热门， 相对较实用的方法有接收 端数字反向传输法和发送端微扰预畸变法等。
数字反向传输法需要分多次交替进行色散补偿和非线性相位补偿， 次 数越多则功耗越大， 芯片难以承受， 并且非线性相位补偿中的相位调整因 子需要优化搜索， 实现难度大； 而微扰预畸变需要系统配置相关信息给发 射机， 尤其是微扰系数计算涉及实数和虚数的指数积分函数， 并且系统传 输距离越长， 所涉及的微扰项越多， 其运算难度也越大。
上述非线性补偿方法的实现非常复杂， 并且性能提升有限， 一般来说 与纠错前误码率对应的 Q参数提升不超过 2dB， 因此光通信研究界和产业 界一直在研究寻找更优的非线性补偿或非线性消除技术。 发明内容
为解决现有存在的技术问题， 本发明实施例提供一种消除非线性效应 的方法、 发射机及接收机。
本发明实施例提供的一种消除非线性效应的方法， 应用于发射机， 包 括：
设置待传输信号和冗余信号， 所述冗余信号为所述待传输信号的 Y轴 对称信号； 在完成设置后， 分别对所述待传输信号和冗余信号执行色散预补偿， 并在完成色散预补偿后执行信号调制。
上述方案中， 对所述待传输信号和冗余信号执行的色散预补偿的补偿 量为系统总色散量的一半。
上述方案中， 所述分别对所述待传输信号和冗余信号执行色散预补偿， 包括：
釆用时域色散补偿或频域色散补偿分别对所述待传输信号和冗余信号 执行色散预补偿。
本发明实施例还提供了一种消除非线性效应的方法， 应用于接收机， 包括：
接收信号并进行数据恢复， 得到待传输信号和冗余信号， 所述冗余信 号为所述待传输信号的 Y轴对称信号；
在得到所述待传输信号和冗余信号后， 分别进行数据判决， 并将冗余 信号与待传输信号对齐， 将待传输信号减去对齐后的冗余信号的共轭信号， 实现对所述待传输信号消除非线性效应；
对消除非线性效应的待传输信号进行数据判决。
上述方案中， 所述接收机为相干接收机。
本发明实施例还提供了一种发射机， 包括： 设置单元、 色散补偿单元 和调制单元， 其中：
所述设置单元， 配置为设置待传输信号和冗余信号， 所述冗余信号为 所述待传输信号的 Y轴对称信号；
所述色散补偿单元， 配置为在所述设置单元完成设置后， 分别对所述 待传输信号和冗余信号执行色散预补偿；
所述调制单元， 配置为在所述色散补偿单元完成色散预补偿后执行信 号调制。
上述方案中， 所述色散补偿单元对所述待传输信号和冗余信号执行的 色散预补偿的补偿量为系统总色散量的一半。
上述方案中， 所述色散补偿单元分别对所述待传输信号和冗余信号执 行色散预补偿， 包括：
釆用时域色散补偿或频域色散补偿分别对所述待传输信号和冗余信号 执行色散预补偿。
本发明实施例还提供了一种接收机， 包括：接收单元、数据恢复单元、 非线性效应消除单元和数据判决单元， 其中：
所述接收单元， 配置为接收信号；
所述数据恢复单元， 配置为进行数据恢复， 得到待传输信号和冗余信 号， 所述冗余信号为所述待传输信号的 Y轴对称信号；
所述非线性效应消除单元， 配置为在所述数据恢复单元得到所述待传 输信号和冗余信号后， 分别进行数据判决， 并将冗余信号与待传输信号对 齐， 将待传输信号减去对齐后的冗余信号的共轭信号， 实现对所述待传输 信号消除非线性效应；
所述数据判决单元， 配置为对消除非线性效应的待传输信号进行数据 判决。
上述方案中， 所述接收机为相干接收机。
本发明实施例还提供了一种计算机可读存储介质， 包括一组计算机 可执行指令， 所述指令用于执行发射机侧的消除非线性效应的方法。
本发明实施例还提供了一种计算机可读存储介质， 包括一组计算机可 执行指令， 所述指令用于执行接收机侧的消除非线性效应的方法。
综上所述， 本发明实施例比现有其他非线性补偿方法实现上更简单， 并且性能更加优异。 附图说明
图 1为本发明实施例的消除非线性效应的方法的发射机侧的流程图； 图 2为本发明实施例的消除非线性效应的方法的接收机侧的流程图； 图 3为本发明实施例的光通信系统的架构图；
图 4 为本发明实施例的消除非线性效应的方法的包含发送机侧和接收 机侧的流程图；
图 5~7为本发明实施例的效果图；
图 8为本发明实施例的发射机的架构图；
图 9为本发明实施例的接收机的架构图。 具体实施方式
以下结合附图对本发明的优选实施例进行详细说明， 应当理解， 以下 所说明的优选实施例仅用于说明和解释本发明， 并不用于限定本发明。
如图 1 所示， 本发明实施例的消除非线性效应的方法在发送机侧， 包 括：
步骤 101 : 设置待传输信号和冗余信号， 冗余信号为待传输信号的 Y 轴对称信号；
信号为偏振复用信号， 但与常规偏振复用技术不同， 其中偏振态 X为 待传输信号 Ex， 偏振态 Y 设置为 Ex 信号的 Y 轴对称信号， 即 Ey=-real(Ex)+i*imag(Ex) ,其中 real表示复数的实部， imag表示复数的虚邵。 信号调制码型不做限制。
步骤 102: 分别对待传输信号和冗余信号执行色散预补偿；
对偏振态 X和 Y信号分别执行色散预补偿， 补偿量为系统总色散量的 一半。 色散补偿方法可以是时域色散补偿， 也可以是频域色散补偿。
步骤 103: 在完成色散预补偿后执行信号调制。
将色散预补偿后的信号完成偏振复用调制。 信号调制与常规光通信系 统的发射机方案相同， 即偏振态 X和 Y数据分别执行信号调制， 釆用数字 模拟转换器（DAC ) 实现， 然后再偏振复用。 如图 2所示， 本发明实施例的消除非线性效应的方法在接收机侧， 包 括：
步骤 201 : 接收信号并进行数据恢复， 得到待传输信号和冗余信号， 冗 余信号为待传输信号的 Y轴对称信号；
按常规相干接收算法恢复出偏振态信号 Ex(t)和 Ey(t)，其中色散补偿量 为系统总色散量的一半。
釆用数字信号处理技术进行数据恢复， 相关算法包括正交归一化、 去 时延、 色散补偿、 时钟恢复、 偏振解复用、 频率预测、 相位预测等等。 本 步骤为现有光通信系统的成熟技术，经过本步骤后获得 X和 Y偏振态信号： Ex(t)和 Ey(t)0
步骤 202: 在得到待传输信号和冗余信号后， 分别进行数据判决， 并将 冗余信号与待传输信号对齐， 将待传输信号减去对齐后的冗余信号的共轭 信号， 实现对待传输信号消除非线性效应；
对 Ex 和 Ey(¾分别进行数据判决， 将 Ex和 Ey判决后执行对齐操作， Ey(t+T)中 τ为 Υ相对 X的时延， Ex(t)和 Ey(t)的非线性效应具有相关性， 最 终将 X 信号减去 Y 的共轭信号实现非线性效应的消除， 通过 Es(t)=Ex(t)-(Ey(t+T))*可消除非线性效应。
步骤 203: 对消除非线性效应的待传输信号进行数据再判决。
将 Es进行数据判决。 数据判决为现有光通信系统的成熟技术。 如图 3所示， 本发明实施例的光通信系统包括发射机 10、接收机 20和 光纤系统 30， 其中， 发射机 10实现信号冗余处理、 预补偿系统一半色散以 及完成偏振复用调制；接收机 20为相干接收机，接收机 20实现信号恢复， 对两个偏振态的信号进行非线性去相关性处理实现非线性效应的消除， 最 后对消除非线性效应的信号进行判决。 光纤系统 30包括但不限于多个光纤 31 和光放大器 32， 例如还可以包括波分复用系统的常见合分波器件等等， 也就是说可适用于现有光通信系统。
发送端设置冗余信号 Ey， 该冗余信号为 Ex 的 Y轴对称信号， 可用 Volterra级数理论进行原理证明， 在传输过程中， Ex和 Ey具有相关性， 可 认为 Ex和 conj(Ey)的非线性畸变完全相同， 因此在接收端两者相减可消除 非线性效应。 如图 4所示， 在本发明的消除非线性效应的方法的另一实施例中包含 发送机侧和接收机侧， 包括：
步骤 401 : 设置待传输信号和冗余信号， 冗余信号为待传输信号的 Y 轴对称信号；
信号为偏振复用信号， 但与常规偏振复用技术不同， 其中偏振态 X为 待传输信号 Ex， 偏振态 Y 设置为 Ex 信号的 Y 轴对称信号， 即 Ey=-real(Ex)+i*imag(Ex) ,其中 real表示复数的实部， imag表示复数的虚邵。 信号调制码型不做限制。
步骤 402: 分别对待传输信号和冗余信号执行色散预补偿；
对偏振态 X和 Y信号分别执行色散预补偿， 补偿量为系统总色散量的 一半。 色散补偿方法可以是时域色散补偿， 也可以是频域色散补偿。
步骤 403: 在完成色散预补偿后执行信号调制；
将色散预补偿后的信号完成偏振复用调制。 信号调制与常规光通信系 统的发射机方案相同， 即偏振态 X和 Y数据分别执行信号调制， 釆用数字 模拟转换器（DAC ) 实现， 然后再偏振复用。
步骤 404: 接收信号并进行数据恢复， 得到待传输信号和冗余信号， 冗 余信号为待传输信号的 Y轴对称信号；
按常规相干接收算法恢复出偏振态信号 Ex(t)和 Ey(t)，其中色散补偿量 为系统总色散量的一半。 釆用数字信号处理技术进行数据恢复， 相关算法包括正交归一化、 去 时延、 色散补偿、 时钟恢复、 偏振解复用、 频率预测、 相位预测等等。 本 步骤为现有光通信系统的成熟技术，经过本步骤后获得 X和 Y偏振态信号： Ex(t)和 Ey(t)0
步骤 405: 在得到待传输信号和冗余信号后， 分别进行数据判决， 并将 冗余信号与待传输信号对齐， 将待传输信号减去对齐后的冗余信号的共轭 信号， 实现对待传输信号消除非线性效应；
对 Ex 和 Ey(¾分别进行数据判决， 将 Ex和 Ey判决后执行对齐操作， Ey(t+T)中 τ为 Υ相对 X的时延， Ex(t)和 Ey(t)的非线性效应具有相关性， 最 终将 X 信号减去 Y 的共轭信号实现非线性效应的消除， 通过 Es(t)=Ex(t)-(Ey(t+T))*可消除非线性效应。
步骤 406: 对消除非线性效应的待传输信号进行数据再判决。
将 Es进行数据判决。 数据判决为现有光通信系统的成熟技术。 图 5~7是利用本发明实施例消除非线性效应的仿真结果示例， 调制码 型为 PDM-QPSK (偏振复用 -四相位调制），单偏振信号的符号速率为 10Gbd， G.652光纤系统， 图 5为 X偏振态信号的星座图， 图 6为 Y偏振态信号的 星座图， 图 7为 Ex-conj(Ey)星座图， 其中 conj表示共轭， 图中 real表示复 数信号的实部， imag表示复数信号的虚部。 从图中不难看出， 单独的 X偏 振态和 Y偏振态的错误矢量幅度（EVM )大约是 0.25~0.26， 经过非线性效 应消除后信号的错误矢量幅度减小到 0.12，错误比特数为 0， 系统传输性能 得到了大幅度的提升。 如图 8所示，本发明实施例还提供了一种发射机， 包括：设置单元 11、 色散补偿单元 12和调制单元 13， 其中：
设置单元 11， 配置为设置待传输信号和冗余信号， 冗余信号为待传输 信号的 Y轴对称信号；
色散补偿单元 12， 配置为在设置单元完成设置后， 分别对待传输信号 和冗余信号执行色散预补偿；
调制单元 13，配置为在色散补偿单元完成色散预补偿后执行信号调制。 色散补偿单元 12对待传输信号和冗余信号执行的色散预补偿的补偿量 为系统总色散量的一半。
色散补偿单元 12分别对待传输信号和冗余信号执行色散预补偿，包括： 釆用时域色散补偿或频域色散补偿分别对待传输信号和冗余信号执行色散 预补偿。
需要说明的是， 上述设置单元 11、 色散补偿单元 12和调制单元 13可 以由发射机的中央处理器（ CPU, Central Processing Unit )、微处理器（ MPU, Micro Processing Unit )、 数字信号处理器（ DSP， Digital Signal Processor ) 或可编程逻辑阵列 （FPGA， Field - Programmable Gate Array ) 实现。 如图 9所示，本发明实施例还提供了一种接收机， 包括：接收单元 21、 数据恢复单元 22、 非线性效应消除单元 23和数据判决单元 24， 其中： 接收单元 21， 配置为接收信号；
数据恢复单元 22，配置为进行数据恢复，得到待传输信号和冗余信号， 冗余信号为待传输信号的 Y轴对称信号；
非线性效应消除单元 23， 配置为在数据恢复单元得到待传输信号和冗 余信号后， 分别进行数据判决， 并将冗余信号与待传输信号对齐， 将待传 输信号减去对齐后的冗余信号的共轭信号， 实现对待传输信号消除非线性 效应；
数据判决单元 24， 配置为对消除非线性效应的待传输信号进行数据判 决。
本发明实施例的接收机可以为相干接收机。 需要说明的是， 上述接收单元 21 可以由接收机的通信功能芯片实现， 数据恢复单元 22、 非线性效应消除单元 23和数据判决单元 24可以由接收 机的 CPU、 MPU、 DSP或 FPGA实现。 本发明实施例还提供了一种计算机可读存储介质， 包括一组计算机 可执行指令， 所述指令用于执行发射机侧的消除非线性效应的方法。
本发明实施例还提供了一种计算机可读存储介质， 包括一组计算机可 执行指令， 所述指令用于执行接收机侧的消除非线性效应的方法。 本领域的技术人员应该明白， 上述的本发明的各模块或各步骤可以用 通用的计算装置来实现， 它们可以集中在单个的计算装置上， 或者分布在 多个计算装置所组成的网络上， 可选地， 它们可以用计算装置可执行的程 序代码来实现， 从而， 可以将它们存储在存储装置中由计算装置来执行， 并且在某些情况下， 可以以不同于此处的顺序执行所示出或描述的步骤， 或者将它们分别制作成各个集成电路模块， 或者将它们中的多个模块或步 骤制作成单个集成电路模块来实现。 这样， 本发明不限制于任何特定的硬 件和软件结合。
以上所述仅为本发明的优选实施例而已， 并不用于限制本发明， 对于 本领域的技术人员来说， 本发明可以有各种更改和变化。 凡在本发明的精 神和原则之内， 所作的任何修改、 等同替换、 改进等， 均应包含在本发明 的保护范围之内。
尽管上文对本发明进行了详细说明， 但是本发明不限于此， 本技术领 域技术人员可以根据本发明的原理进行各种修改。 因此， 凡按照本发明原 理所作的修改， 都应当理解为落入本发明的保护范围。

Claims

权利要求书
1、 一种消除非线性效应的方法， 应用于发射机， 包括：
设置待传输信号和冗余信号， 所述冗余信号为所述待传输信号的 Y 轴对称信号；
在完成设置后， 分别对所述待传输信号和冗余信号执行色散预补偿， 并在完成色散预补偿后执行信号调制。
2、 如权利要求 1所述的方法， 其中： 对所述待传输信号和冗余信号 执行的色散预补偿的补偿量为系统总色散量的一半。
3、 如权利要求 1或 2所述的方法， 其中： 所述分别对所述待传输信 号和冗余信号执行色散预补偿， 包括：
釆用时域色散补偿或频域色散补偿分别对所述待传输信号和冗余信 号执行色散预补偿。
4、 一种消除非线性效应的方法， 应用于接收机， 包括：
接收信号并进行数据恢复， 得到待传输信号和冗余信号， 所述冗余 信号为所述待传输信号的 Y轴对称信号；
在得到所述待传输信号和冗余信号后， 分别进行数据判决， 并将冗 余信号与待传输信号对齐， 将待传输信号减去对齐后的冗余信号的共轭 信号， 实现对所述待传输信号消除非线性效应；
对消除非线性效应的待传输信号进行数据判决。
5、 如权利要求 4所述的方法， 其中： 所述接收机为相干接收机。
6、一种发射机， 包括：设置单元、 色散补偿单元和调制单元，其中： 所述设置单元， 配置为设置待传输信号和冗余信号， 所述冗余信号 为所述待传输信号的 Y轴对称信号；
所述色散补偿单元， 配置为在所述设置单元完成设置后， 分别对所 述待传输信号和冗余信号执行色散预补偿； 所述调制单元， 配置为在所述色散补偿单元完成色散预补偿后执行 信号调制。
7、 如权利要求 6所述的发射机， 其中， 所述色散补偿单元对所述待 传输信号和冗余信号执行的色散预补偿的补偿量为系统总色散量的一半。
8、 如权利要求 6所述的发射机， 其中， 所述色散补偿单元分别对所 述待传输信号和冗余信号执行色散预补偿， 包括：
釆用时域色散补偿或频域色散补偿分别对所述待传输信号和冗余信 号执行色散预补偿。
9、 一种接收机， 包括： 接收单元、 数据恢复单元、 非线性效应消除 单元和数据判决单元， 其中：
所述接收单元， 配置为接收信号；
所述数据恢复单元， 配置为进行数据恢复， 得到待传输信号和冗余 信号， 所述冗余信号为所述待传输信号的 Y轴对称信号；
所述非线性效应消除单元， 配置为在所述数据恢复单元得到所述待 传输信号和冗余信号后， 分别进行数据判决， 并将冗余信号与待传输信 号对齐， 将待传输信号减去对齐后的冗余信号的共轭信号， 实现对所述 待传输信号消除非线性效应；
所述数据判决单元， 配置为对消除非线性效应的待传输信号进行数 据判决。
10、如权利要求 9所述的接收机，其中， 所述接收机为相干接收机。
11、 一种计算机可读存储介质， 包括一组计算机可执行指令， 所述 指令用于执行权利要求 1-3任一项所述的消除非线性效应的方法。
12、 一种计算机可读存储介质， 包括一组计算机可执行指令， 所述 指令用于执行权利要求 4-5任一项所述的消除非线性效应的方法。
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