CN106452593B - The construction method and device and nonlinear noise suppressing method and system of filter - Google Patents
The construction method and device and nonlinear noise suppressing method and system of filter Download PDFInfo
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- CN106452593B CN106452593B CN201610371872.8A CN201610371872A CN106452593B CN 106452593 B CN106452593 B CN 106452593B CN 201610371872 A CN201610371872 A CN 201610371872A CN 106452593 B CN106452593 B CN 106452593B
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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
- H04B10/25133—Arrangements specific to fibre transmission for the reduction or elimination of distortion or dispersion due to chromatic dispersion including a lumped electrical or optical dispersion compensator
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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
- H04B10/07—Arrangements for monitoring or testing transmission systems; Arrangements for fault measurement of transmission systems
- H04B10/075—Arrangements for monitoring or testing transmission systems; Arrangements for fault measurement of transmission systems using an in-service signal
- H04B10/079—Arrangements for monitoring or testing transmission systems; Arrangements for fault measurement of transmission systems using an in-service signal using measurements of the data signal
- H04B10/0795—Performance monitoring; Measurement of transmission parameters
- H04B10/07951—Monitoring or measuring chromatic dispersion or PMD
Abstract
The invention discloses the construction method of filter and device and nonlinear noise suppressing method and systems.The present invention is based on Gaussian noise model (Gaussian noise model, GN), interchannel nonlinear impairments caused by XPM in fibre-optic transmission system (FOTS) are obtained using single order perturbation theory, according to the channel compensation filter based on the related adaptation of carrier wave relevant to the big little structure of center channel effect and channel spacing and interference channel transmitting sequence of the channel under different frequency, the power of different channels in fiber channel model can be dynamically distributed, and nonlinear noise is compensated according to the principle of digit reverse transmission algorithm, since non-linear effects of all interference channels to central channel need not be calculated, therefore the complexity of compensation DBP algorithms can effectively be reduced.
Description
Technical field
The present invention relates to the optical transport technology fields of field of communication technology, more particularly to the channel based on carrier wave correlation adaptation
The construction method and interchannel nonlinear noise suppressing method and system of compensating filter.
Background technology
In recent years, the video techniques such as high definition, 3D, ultra high-definition rapidly develop, and the business such as big data, cloud computing, cloud storage need
Explosive growth is asked, more stringent requirements are proposed to fibre system transmission range and capacity, therefore ultrahigh speed long-distance optical fiber passes
Defeated to become one of studies in China hot spot, people faster, apart from longer target stride forward towards speed always.
The breakthrough each time of transmission capacity and transmission range is always derived from the use of new technology and overcoming for critical issue,
But new problem is also thus introduced, limit the further development of fibre-optic transmission system (FOTS).Intermode dispersion from early stage and loss
Limitation, group velocity dispersion limitation finally, nonlinear fiber by now and dispersion synthesis limitation, with carrying for transmission rate
High and transmission range growth, fibre-optic transmission system (FOTS) problems faced are also constantly changing.
In large capacity fiber optic transmission system long haul, multi-span cascade, multichannel is simultaneously deposited, and optical fiber interaction length adds
Greatly, make the accumulation of ASE noises, dispersion and nonlinear effect more serious, limit the property of large capacity long distance optical transmission system
Energy.In recent years, both at home and abroad have many researchers in large capacity long distance optical transmission system dispersion and nonlinear effect
And its compensation method is studied, and is concentrated mainly on and is analyzed influence in fibre-optic transmission system (FOTS) of each nonlinear effect, mutually
Between influence and nonlinear impairments compensation method.
Current nonlinear impairments compensation method includes mainly two classes：Optical domain compensation and electrical domain compensation.With extensive collection
At the development of circuit so that the dispersion of system and nonlinear compensation are possibly realized using DSP technologies, not only flexibility is stronger,
And cost is relatively low so that business practicality is possibly realized.In electrical domain compensation, the most commonly used is reverse transfer algorithm, passes through mould
The reversed digital transmission link of quasi- optical signal eliminates optical signal suffered dispersion and non-linear shadow in transmission process to reach
Loud purpose.DBP algorithms need that the nonlinear noise in channel is estimated and predicted first, and currently used method is sometimes
Domain Gaussian noise model (GN model) and frequency domain logarithm perturbation model (FRLP model) etc..But answering due to DBP algorithms
Miscellaneous degree, compensation effect are bad.
Invention content
The embodiment of the present invention is designed to provide a kind of structure for the channel compensation filter being adapted to based on carrier wave correlation
Method and apparatus and interchannel nonlinear noise suppressing method and system, realization compensate nonlinear noise into Mobile state, to
The bit error rate for effectively reducing channel, improves system performance.Specific technical solution is as follows：
In a first aspect, the embodiment of the invention discloses the construction method of filter, include the following steps：
S1) transmitting terminal send checking sequence, data-signal after MZ modulators modulates by being multiplexed into fiber channel,
, by demultiplexing and coherent reception, coherent detection data-signal is being obtained after the transmission of M spans；
S2 reversed virtual fiber link) is established according to the principle of " first-in last-out " using DBP algorithms, to coherent detection data
Signal carries out dispersion compensation and nonlinear compensation, and before the compensation of each span plus optical attenuator decays to optical signal；
S3) repeat the above steps S1) and S2), obtain influence coefficients of the different interference channels to destination channel, including from phase
Influence coefficient of the position modulation to signal, influence of noise coefficient caused by Cross-phase Modulation；
S4) the influence coefficient using different interference channels to destination channel, obtains different interference channels and is made to destination channel
At XPM phase noises and its variance；
S5 different interference channel XPM phase noises and its variances caused by destination channel) are utilized, different interference letters are obtained
Auto-correlation coefficient of the road to the XPM phase noises of destination channel；
S6 different frequency) is obtained to the auto-correlation coefficient of the XPM phase noises of destination channel using different interference channels
Influence size of the channel to central channel XPM effects；
S7 it) utilizes the channel of different frequency to the influence size of central channel XPM effects, obtains and channel spacing and interference
The relevant channel compensation filter based on carrier wave correlation adaptation of channel transmitting sequence.
Further, step S4) in, the channel compensation filter based on carrier wave correlation adaptation is expressed as：
Wherein,For different interference channel XPM phase noises caused by destination channel, ωk-ωsFor channel spacing,
{b0It is interference channel transmitting sequence, L is transmission range, and γ is nonlinear factor, β2For second-order dispersion parameter.
Further, the step S11) in, fiber channel is built using the symmetrical split-step fast Fourier transformed method of fixed step size
Mould, step-length h, in step-length h, linear operator and nonlinear operator are mutual indepedent, each span carries out n times compensation, passes altogether
Defeated M spans are followed by image intensifer in each span and are amplified to optical signal.
Further, the step S2) in, the nonlinear compensation carries out in each span centre position, for compensation
Filter is：
Further, the step S2) in, the dispersion compensation uses frequency domain filter, and the filter for compensation indicates
For：
Wherein, λ-carrier wavelength, ω-carrier frequency, S- chromatic dispersion gradients, the c- lighies velocity.
Further, in the nonlinear compensation, the optical signal of each channel calculates the intersection of other channels using XPM modules
Influence of the phase-modulation to the channel, wherein the calculation formula of the XPM modules of q-th of channel is：
Wherein, EoutOutput light field.
Second aspect, the embodiment of the invention discloses the construction devices of filter, including：
Coherent detection signal acquisition module sends checking sequence for transmitting terminal, and data-signal passes through MZ modulators modulates
Afterwards by being multiplexed into fiber channel, by demultiplexing and coherent reception, coherent detection data are being obtained after the transmission of M spans
Signal；
Coherent detection signal compensation module, it is reversed virtual for being established according to the principle of " first-in last-out " using DBP algorithms
Optical fiber link carries out dispersion compensation and nonlinear compensation to coherent detection data-signal, adds light decay before the compensation of each span
Subtract device to decay to optical signal；
DSP processing modules, for passing through the coherent detection signal acquisition module and coherent detection signal compensation module
Repeatedly processing, obtains different influence coefficients of the interference channels to destination channel, including influence coefficient of the Self-phase modulation to signal,
Influence of noise coefficient caused by Cross-phase Modulation；
XPM phase noise acquisition modules obtain different for the influence coefficient using different interference channels to destination channel
Interfere channel XPM phase noises and its variance caused by destination channel；
XPM auto-correlation coefficient acquisition modules, for utilizing different interference channel XPM phase noises caused by destination channel
And its variance, obtain auto-correlation coefficient of the different interference channels to the XPM phase noises of destination channel；
The XPM effect acquisition modules of difference interference channel, for the XPM phases using different interference channels to destination channel
The auto-correlation coefficient of noise obtains influence size of the channel to central channel XPM effects of different frequency；
Channel compensation filter acquisition module, the influence for the channel using different frequency to central channel XPM effects
Size obtains and channel spacing and interferes the relevant channel compensation filter based on the related adaptation of carrier wave of channel transmitting sequence.
The third aspect, the embodiment of the invention discloses nonlinear noise suppressing methods, including：
Reversed virtual fiber link is established according to the principle of " first-in last-out " using DBP algorithms；
In reversed virtual fiber link, the channel compensation being adapted to based on carrier wave correlation is used to coherent detection data-signal
Filter calculates the XPM phase noise compensation values under different channels；
According to the XPM phase noise compensation values under different channels, the XPM phase noises in destination channel are compensated.
Further, the channel compensation filter based on carrier wave correlation adaptation is：
Wherein,For different interference channel XPM phase noises caused by destination channel, ωk-ωsFor channel spacing,
{b0It is interference channel transmitting sequence, L is transmission range, and γ is nonlinear factor, β2For second-order dispersion parameter.
Fourth aspect, the embodiment of the invention discloses nonlinear noise suppression systems, including：
Reversed virtual fiber link establishment module, it is reversed for being established according to the principle of " first-in last-out " using DBP algorithms
Virtual fiber link；
XPM phase noise compensation computing modules, for being adopted to coherent detection data-signal in reversed virtual fiber link
The XPM phase noise compensation values under different channels are calculated with the channel compensation filter being adapted to based on carrier wave correlation；
XPM phase noise compensation modules are used for according to the XPM phase noise compensation values under different channels, to destination channel
In XPM phase noises compensate.
As seen from the above technical solutions, the embodiment of the present invention receives the symbol of destination channel in receiving terminal, obtains
To uncompensated sequence { rk, by { rkObtainValue, according to the channel under different frequency to the size of center channel effect
Construction and channel spacing and interfere the relevant channel compensation filter based on the related adaptation of carrier wave of channel transmitting sequence, to optical fiber
The power of different channels is dynamically distributed in channel model, and according to the principle of digit reverse transmission algorithm to nonlinear noise
It compensates, since non-linear effects of all interference channels to central channel need not be calculated, can effectively reduce existing
There is the complexity of DSP backoff algorithms.
Description of the drawings
In order to more clearly explain the embodiment of the invention or the technical proposal in the existing technology, to embodiment or will show below
There is attached drawing needed in technology description to be briefly described, it should be apparent that, the accompanying drawings in the following description is only this
Some embodiments of invention for those of ordinary skill in the art without creative efforts, can be with
Obtain other attached drawings according to these attached drawings.
Fig. 1 is the large capacity long-distance WDM optical transmission system structural schematic diagram of the embodiment of the present invention；
Fig. 2 is the fiber channel model structure schematic diagram of the embodiment of the present invention；
Fig. 3 is nonlinear compensation processing flow schematic diagram in wdm system of the embodiment of the present invention；
Fig. 4 is the interchannel nonlinear noise suppressing method docking that the utilization of the embodiment of the present invention is adapted to based on carrier wave correlation
The collection of letters number carries out a processing flow schematic diagram for nonlinear compensation；
Fig. 5 is curve synoptic diagram of the different interference channels to center channel non-linearity effects of the embodiment of the present invention；
Fig. 6 is the frequency characteristic schematic diagram for the filter of the embodiment of the present invention obtained according to Fig. 5；
Fig. 7 is positive transmission schematic diagram of each span of the embodiment of the present invention in fiber channel；
Fig. 8 is that each span of the embodiment of the present invention utilizes reverse transfer schematic diagram in the virtual fiber link of DBP algorithms.
Specific implementation mode
Following will be combined with the drawings in the embodiments of the present invention, and technical solution in the embodiment of the present invention carries out clear, complete
Site preparation describes, it is clear that described embodiments are only a part of the embodiments of the present invention, instead of all the embodiments.It is based on
Embodiment in the present invention, it is obtained by those of ordinary skill in the art without making creative efforts every other
Embodiment shall fall within the protection scope of the present invention.
An explanation is done to the function and its parameter used in the embodiment of the present invention first below：
E (z, t)-light field becomes envelope slowly；
EinInput light field；
EoutOutput light field；
γ-nonlinear factor；
The gain amplifier of G-amplifier；
H (ω) is the transmission function of dispersion compensating filter, wherein：
λ-carrier wavelength ω-carrier frequency D- abbe number S- chromatic dispersion gradient c- the lighies velocity；
ΔakAt the z=L moment, the signal received is influenced by nonlinear effect；
L-transmission range；
Sh,u,mCharacterize size of the Self-phase modulation (SPM) to phase noise contribution；
Xh,u,mCharacterize size of the Cross-phase Modulation (XPM) to phase noise contribution；
θ-interference channel XPM phase noises caused by destination channel；
Phase noise variance；
Rk,s(l) auto-correlation function of the phase noise of-difference interference channel with central channel；
ωk-ωsChannel spacing.
The present invention is directed to long range large capacity WDM fiber Transmission system, using digit reverse transmission algorithm (DBP), to color
It dissipates and non-linear carry out hybrid compensation.Entire Transmission system is as shown in Figure 1, fiber channel models as shown in Fig. 2, WDM transmission system
Dispersion non-linearity hybrid compensation modular algorithm block diagram in system is as shown in Figure 3.
Embodiment 1
Present embodiment discloses the construction methods of filter, include the following steps：
S1) transmitting terminal send checking sequence, data-signal after MZ modulators modulates by being multiplexed into fiber channel,
, by demultiplexing and coherent reception, coherent detection data-signal is being obtained after the transmission of M spans；
S2 reversed virtual fiber link) is established according to the principle of " first-in last-out " using DBP algorithms, to coherent detection data
Signal carries out dispersion compensation and nonlinear compensation, and before the compensation of each span plus optical attenuator decays to optical signal；Often
One span DBP algorithm block diagrams are as shown in Figure 8.
S3) repeat the above steps S1) and S2), obtain influence coefficients of the different interference channels to destination channel, including from phase
Influence coefficient of the position modulation to signal, influence of noise coefficient caused by Cross-phase Modulation；
S4) the influence coefficient using different interference channels to destination channel, obtains different interference channels and is made to destination channel
At XPM phase noises and its variance；
S5 different interference channel XPM phase noises and its variances caused by destination channel) are utilized, different interference letters are obtained
Auto-correlation coefficient of the road to the XPM phase noises of destination channel；
S6) auto-correlation coefficient of the XPM phase noises of destination channel is obtained according to principle of stacking using different interference channels
Obtain influence size of the channel to central channel XPM effects of different frequency；
S7 it) utilizes the channel of different frequency to the influence size of central channel XPM effects, obtains and channel spacing and interference
The relevant channel compensation filter based on carrier wave correlation adaptation of channel transmitting sequence.
Further, the step S11) in, fiber channel using fixed step size symmetrical step Fourier (SSF) algorithm into
Row modeling (as shown in Figure 2), in step-length h, linear operatorAnd nonlinear operatorIndependently of each other.Wherein α is optical fiber loss factor, β2It is fibre-optical dispersion constant, β3It is second order group velocity dispersion
Slope, γ are nonlinear factors, and A (z, t) is optical field envelope.Assuming that each span length is Lspan, n times benefit is carried out to span
It repays, then compensates times N=Lspan/ h, each span are followed by image intensifer and are amplified to optical signal, transmit M spans altogether, i.e., always
Conveying length is L=M × Lspan.Each span transmission block diagram is as shown in Figure 7.
Further, the step S2) in, in the nonlinear compensation, the optical signal of each channel is calculated using XPM modules
Influence of the Cross-phase Modulation of other channels to the channel, wherein the calculation formula of the XPM modules of q-th of channel is：
Wherein, EoutFor output light field.
Further, the step S2) in, using symmetrical split-step fast Fourier transformed method, the nonlinear compensation is in each span
Centre position carries out, and the filter for compensation is：
It should be noted that step S2) in nonlinear impairments penalty function filter be used for eliminating image intensifer and bringing
Spontaneous radiation (ASE) noise, design the filter using window function metht, inhibit the bandwidth of signal, limit high frequency noise components,
When window function is selected as Gaussian, expression formula is as follows：
Wherein, fcIt is the centre frequency of filter, B is the three dB bandwidth of filter, and m is filter order.Appropriate selection
The three dB bandwidth parameter of the filter so that under the premise of bandwidth meets the requirements, side lobe attenuation is larger for it, to realize effectively filter
Except the purpose of noise.
Further, the step S2) in, the dispersion compensation uses frequency domain filter, and the filter for compensation indicates
For：
Further, step S4) in, the channel compensation filter based on carrier wave correlation adaptation is expressed as：
Wherein,For different interference channel XPM phase noises caused by destination channel, ωk-ωsFor channel spacing,
{b0It is interference channel transmitting sequence, L is transmission range, and γ is nonlinear factor, β2For second-order dispersion parameter.
It should be noted that step S4)-S7) the specific method is as follows：
One section of checking sequence { a is sent in transmitting terminal destination channelk, interference channel transmitting sequence { bk, according to time-domain analysis
Model, the zeroth order solution for transmitting signal are represented by：
Wherein, g(0)(z, t)=Ψ (z) g (0, t),G (0, t) has orthogonal property.
The single order solution of signal can be obtained by solving non-linear Schrodinger equation (NLSE)：
Wherein, f (z) represents the loss characteristic of link, and the solution of equation (2) is shown below：
U (L, t)=u(0)(L,t)+u(1)(L,t) (4)
Pass through matched filtering, u in receiving terminal(0)(L, t) does not contribute nonlinear phase noise, u(1)(L, t) is to non-thread
The contribution of property noise is represented by：
Formula (3) is updated in formula (5), can be obtained：
Wherein, Sh,k,mIndicate influence of the Self-phase modulation to signal, Xh,k,mIndicate noise caused by Cross-phase Modulation.
Work as h=0, when u=m can be obtained it is non-linear caused by phase noise, be shown below：
Wherein,For phase noise, variance is：
It should be noted that the present invention only considers big dispersion accumulated value and the condition without embedding dispersion compensation, at this
Under part, X0,m,mIt can be with being expressed as：
Therefore the variance that phase noise can be obtained is：
The auto-correlation function of phase noise is：
Wherein, [u]+=max { u, 0 }
The formula indicates influence size of the channel to central channel XPM effects of different frequency, when interference channel distance center
When channel is remote enough, the non-linear effects of central channel can be ignored.
Embodiment 2
The embodiment of the invention discloses the construction devices of the filter of the method using embodiment 1, including：
Coherent detection signal acquisition module sends checking sequence for transmitting terminal, and data-signal passes through MZ modulators modulates
Afterwards by being multiplexed into fiber channel, by demultiplexing and coherent reception, coherent detection data are being obtained after the transmission of M spans
Signal；
Coherent detection signal compensation module, it is reversed virtual for being established according to the principle of " first-in last-out " using DBP algorithms
Optical fiber link carries out dispersion compensation and nonlinear compensation to coherent detection data-signal, adds light decay before the compensation of each span
Subtract device to decay to optical signal；
DSP processing modules, for passing through the coherent detection signal acquisition module and coherent detection signal compensation module
Repeatedly processing, obtains different influence coefficients of the interference channels to destination channel, including influence coefficient of the Self-phase modulation to signal,
Influence of noise coefficient caused by Cross-phase Modulation.
XPM phase noise acquisition modules obtain different for the influence coefficient using different interference channels to destination channel
Interfere channel XPM phase noises and its variance caused by destination channel；
XPM auto-correlation coefficient acquisition modules, for utilizing different interference channel XPM phase noises caused by destination channel
And its variance, obtain auto-correlation coefficient of the different interference channels to the XPM phase noises of destination channel；
The XPM effect acquisition modules of difference interference channel, for the XPM phases using different interference channels to destination channel
The auto-correlation coefficient of noise obtains influence size of the channel to central channel XPM effects of different frequency；
Channel compensation filter acquisition module, the influence for the channel using different frequency to central channel XPM effects
Size obtains and channel spacing and interferes the relevant channel compensation filter based on the related adaptation of carrier wave of channel transmitting sequence.
Embodiment 3
The embodiment of the invention discloses using embodiment 1 filter construction method nonlinear noise suppressing method,
Including：
Reversed virtual fiber link is established according to the principle of " first-in last-out " using DBP algorithms, coherent detection data are believed
Number use calculates the XPM phase noise compensation values under different channels based on the channel compensation filter that carrier wave correlation is adapted to, to mesh
XPM phase noises in mark channel compensate.
Further, the channel compensation filter based on carrier wave correlation adaptation is：
Wherein,For different interference channel XPM phase noises caused by destination channel, ωk-ωsFor channel spacing,
{b0It is interference channel transmitting sequence, L is transmission range, and γ is nonlinear factor, β2For second-order dispersion parameter.
Specifically, before carrying out optical signal transmission, one section of checking sequence is first sent, obtains different interference channels to center
The influence coefficient of channel, the interchannel nonlinear noise rejects trap R- being adapted to based on carrier wave correlation using the coefficients to construct
Filter carries out nonlinear compensation using the filter to the signal received, and calculation process is as shown in Figure 4, in big dispersion
Accumulation not in the optical fiber link of dispersion management, when the modulation format for emitting signal is 16QAM, obtains Rθ(l) influence curve
As shown in figure 5, the frequency characteristic of the filter frequencies R-filter obtained according to this curve is as shown in Figure 6.Curve generation in Fig. 5
The different interference channels of table have power selectability filter to the sizes of center channel non-linearity effects according to this curve construction
Wave device, compensates nonlinear noise, by, it is found that when interfering channel distance center channel remote enough, interfering channel in figure
The influence of noise can be ignored, therefore the complexity of DBP algorithms can be greatly reduced in the range of error allows.
Embodiment 4
The embodiment of the invention discloses the nonlinear noise suppression systems of the method using embodiment 3, including：
Reversed virtual fiber link establishment module, it is reversed for being established according to the principle of " first-in last-out " using DBP algorithms
Virtual fiber link；
XPM phase noise compensation computing modules, for being adopted to coherent detection data-signal in reversed virtual fiber link
The XPM phase noise compensation values under different channels are calculated with the channel compensation filter being adapted to based on carrier wave correlation；
XPM phase noise compensation modules are used for according to the XPM phase noise compensation values under different channels, to destination channel
In XPM phase noises compensate.
Embodiment 5
Concrete application of the multichannel dispersion non-linearity hybrid compensation algorithm in long range large capacity WDM fiber Transmission system
Process is as follows：
S1, transmitting terminal are modulated using 16QAM, and symbol mapping mode maps for Gray code, and Pulse shaped filter is selected as
Gaussian pulse meets following relational expression：
S2, data-signal are by being multiplexed into fiber channel after MZ modulators modulates, and channel model is using symmetrical point
Fourier algorithm is walked, by demultiplexing and coherent reception after being transmitted by M spans, into DSP processing modules.
S3, the dispersion in DSP processing modules using digit reverse transmission algorithm to signal and non-linear carry out hybrid compensation,
Reversed virtual fiber link is established according to the principle of " first-in last-out ", before the compensation of each span plus optical attenuator is to optical signal
Decay.Wherein,
The formula of optical attenuator is
Specifically, in linear compensating unit, the dispersion compensation of signal is realized by frequency domain filter method.Non-linear
Compensating unit, the optical signal of each channel calculate influence of the Cross-phase Modulation to the channel of other channels by XPM modules.
S4, to advanced optimize the compensation effect of algorithm, before carrying out optical signal transmission, first send one section inspection sequence
Row obtain influence coefficient of the different interference channels to central channel, the channel being adapted to based on carrier wave correlation using the coefficients to construct
Between nonlinear noise rejects trap R-filter, nonlinear compensation is carried out to the signal that receives using the filter, is calculated
Flow is as shown in Figure 4, and in big dispersion accumulation, not in the optical fiber link of dispersion management, the modulation format for emitting signal is
When 16QAM, R is obtainedk,s(l) influence curve as shown in figure 5, the filter frequencies R-filter obtained according to this curve frequency
Rate characteristic is as shown in Figure 6.
According to above-described embodiment it is found that being received to the symbol of destination channel in receiving terminal, uncompensated sequence is obtained
{rk, by { rkObtain Rk,s(l) value has frequency according to the channel under different frequency to the big little structure of center channel effect
The filter of selection function dynamically distributes the power of different channels in fiber channel model, and is passed according to digit reverse
The principle of defeated algorithm compensates nonlinear noise, due to that need not calculate all interference channels to the non-linear of central channel
It influences, therefore can effectively reduce the complexity of backoff algorithm.
It should be noted that herein, relational terms such as first and second and the like are used merely to a reality
Body or operation are distinguished with another entity or operation, are deposited without necessarily requiring or implying between these entities or operation
In any actual relationship or order or sequence.Moreover, the terms "include", "comprise" or its any other variant are intended to
Non-exclusive inclusion, so that the process, method, article or equipment including a series of elements is not only wanted including those
Element, but also include other elements that are not explicitly listed, or further include for this process, method, article or equipment
Intrinsic element.In the absence of more restrictions, the element limited by sentence "including a ...", it is not excluded that
There is also other identical elements in process, method, article or equipment including the element.
Each embodiment in this specification is all made of relevant mode and describes, identical similar portion between each embodiment
Point just to refer each other, and each embodiment focuses on the differences from other embodiments.Especially for system reality
For applying example, since it is substantially similar to the method embodiment, so description is fairly simple, related place is referring to embodiment of the method
Part explanation.
The foregoing is merely illustrative of the preferred embodiments of the present invention, is not intended to limit the scope of the present invention.It is all
Any modification, equivalent replacement, improvement and so within the spirit and principles in the present invention, are all contained in protection scope of the present invention
It is interior.
Claims (10)
1. the construction method of filter, which is characterized in that include the following steps：
S1) transmitting terminal sends checking sequence, and data-signal, by being multiplexed into fiber channel, is passing through after MZ modulators modulates
It crosses after the transmission of M spans by demultiplexing and coherent reception, obtains coherent detection data-signal；
S2 reversed virtual fiber link) is established according to the principle of " first-in last-out " using DBP algorithms, to coherent detection data-signal
Dispersion compensation and nonlinear compensation are carried out, before the compensation of each span plus optical attenuator decays to optical signal；
S3) repeat the above steps S1) and S2), obtain influence coefficients of the different interference channels to destination channel, including from phase tune
Make influence coefficient to signal, influence of noise coefficient caused by Cross-phase Modulation；
S4) the influence coefficient using different interference channels to destination channel, obtains different interference channels caused by destination channel
XPM phase noises and its variance；
S5 different interference channel XPM phase noises and its variances caused by destination channel) are utilized, different interference channels pair are obtained
The auto-correlation coefficient of the XPM phase noises of destination channel；
S6 the channel of different frequency) is obtained to the auto-correlation coefficient of the XPM phase noises of destination channel using different interference channels
To the influence size of central channel XPM effects；
S7 it) utilizes the channel of different frequency to the influence size of central channel XPM effects, obtains and channel spacing and interference channel
The relevant channel compensation filter based on carrier wave correlation adaptation of transmitting sequence.
2. according to the method described in claim 1, it is characterized in that, step S4) in, the channel based on carrier wave correlation adaptation
Compensating filter is expressed as：
Wherein, Rk,s(l) interfere the phase noise of channels with the auto-correlation function of central channel to be different, l is after normalizing
Channel spacing, T are time constant,For different interference channel XPM phase noises caused by destination channel, ωk-ωsFor
Channel spacing, { b0It is interference channel transmitting sequence, L is transmission range, and γ is nonlinear factor, β2For second-order dispersion parameter.
3. according to the method described in claim 1, the it is characterized in that, step S1) in, fiber channel is using fixed step size
Symmetrical split-step fast Fourier transformed method is modeled, and step-length h, in step-length h, linear operator and nonlinear operator are mutual indepedent, often
One span carries out n times compensation, transmits M spans altogether, is followed by image intensifer in each span and is amplified to optical signal.
4. according to the method described in claim 1, the it is characterized in that, step S2) in, the nonlinear compensation it is each across
Section centre position carries out, and the filter for compensation is：
5. according to the method described in claim 1, the it is characterized in that, step S2) in, the dispersion compensation is filtered using frequency domain
Wave device, the filter for compensation are expressed as：
Wherein, H (ω) is the transmission function of dispersion compensating filter, and D is abbe number, and h is the step-length chosen, λ-carrier wave wave
It is long, ω-carrier frequency, S- chromatic dispersion gradients, the c- lighies velocity.
6. according to the method described in claim 1, it is characterized in that, in the nonlinear compensation, the optical signal of each channel is adopted
Influence of the Cross-phase Modulation to the channel of other channels is calculated with XPM modules, wherein the meter of the XPM modules of q-th of channel
Calculating formula is：
Wherein, EoutOutput light field.
7. the construction device of the filter using method described in claim 1, which is characterized in that including：
Coherent detection signal acquisition module sends checking sequence for transmitting terminal, and data-signal passes through after MZ modulators modulates
It crosses and is multiplexed into fiber channel, by demultiplexing and coherent reception, coherent detection data letter is being obtained after the transmission of M spans
Number；
Coherent detection signal compensation module, for establishing reversed virtual fiber according to the principle of " first-in last-out " using DBP algorithms
Link carries out dispersion compensation and nonlinear compensation to coherent detection data-signal, adds optical attenuator before the compensation of each span
Decay to optical signal；
DSP processing modules, for passing through the multiple of the coherent detection signal acquisition module and coherent detection signal compensation module
Processing, obtains different influence coefficients of the interference channels to destination channel, including influence coefficient of the Self-phase modulation to signal, intersects
Influence of noise coefficient caused by phase-modulation；
XPM phase noise acquisition modules obtain different interference for the influence coefficient using different interference channels to destination channel
Channel XPM phase noises and its variance caused by destination channel；
XPM auto-correlation coefficient acquisition modules, for using different interference channels caused by destination channel XPM phase noises and its
Variance obtains auto-correlation coefficient of the different interference channels to the XPM phase noises of destination channel；
The XPM effect acquisition modules of difference interference channel, for the XPM phase noises using different interference channels to destination channel
Auto-correlation coefficient, obtain influence size of the channel to central channel XPM effects of different frequency；
Channel compensation filter acquisition module, for the channel using different frequency to the influence size of central channel XPM effects
It obtains and channel spacing and interferes the relevant channel compensation filter based on the related adaptation of carrier wave of channel transmitting sequence.
8. using the nonlinear noise suppressing method of filter described in claim 1, which is characterized in that including：
Reversed virtual fiber link is established according to the principle of " first-in last-out " using DBP algorithms；
In reversed virtual fiber link, the channel compensation being adapted to based on carrier wave correlation is used to filter coherent detection data-signal
Device calculates the XPM phase noise compensation values under different channels；
According to the XPM phase noise compensation values under different channels, the XPM phase noises in destination channel are compensated.
9. according to the method described in claim 8, it is characterized in that, the channel compensation filter based on carrier wave correlation adaptation
For：
Wherein, Rk,s(l) interfere the phase noise of channels with the auto-correlation function of central channel to be different, l is after normalizing
Channel spacing, T are time constant；For different interference channel XPM phase noises caused by destination channel, ωk-ωsFor letter
Road interval, { b0It is interference channel transmitting sequence, L is transmission range, and γ is nonlinear factor, β2For second-order dispersion parameter.
10. the nonlinear noise suppression system of the method using claim 8, which is characterized in that including：
Reversed virtual fiber link establishment module, it is reversed virtual for being established according to the principle of " first-in last-out " using DBP algorithms
Optical fiber link；
XPM phase noise compensation computing modules, for using base to coherent detection data-signal in reversed virtual fiber link
The XPM phase noise compensation values under different channels are calculated in the channel compensation filter of carrier wave correlation adaptation；
XPM phase noise compensation modules are used for according to the XPM phase noise compensation values under different channels, in destination channel
XPM phase noises compensate.
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