CN106452593A - Filter construction method and device and nonlinear noise suppression method and system - Google Patents

Abstract

The invention discloses a filter construction method and device and a nonlinear noise suppression method and system. The inter-channel nonlinear damage caused by XPM in an optical fiber transmission system is obtained by using the first order perturbation theory based on a Gaussian noise model (GN). A channel compensation filter which is relevant to channel spacing and interference channel transmitting sequences and based on carrier relevant adaptation is constructed according to the size of the influence of channels under different frequencies on the center channel. The power of different channels in an optical fiber channel model can be dynamically allocated, and nonlinear noise can be compensated according to the principle of a digital reverse transmission algorithm. The nonlinear influence of all the interference channels on the center channel does not need to be calculated so that the complexity of a compensation DBP algorithm can be effectively reduced.

Description

The construction method of wave filter and device and nonlinear noise suppressing method and system

Technical field

The present invention relates to the optical transport technology field of communication technical field, the more particularly, to channel based on the related adaptation of carrier wave The construction method of compensating filter and interchannel nonlinear noise suppressing method and system.

Background technology

In recent years, the video technique such as high definition, 3D, ultra high-definition develops rapidly, and the business such as big data, cloud computing, cloud storage needs Ask explosive growth, fibre system transmission range and capacity are put forward higher requirement, therefore ultrahigh speed long-distance optical fiber passes Defeated become one of studies in China focus, people faster, apart from longer target stride forward towards speed always.

Transmission capacity and the breakthrough each time of transmission range, be always derived from new technology using with the overcoming of key issue, But also thus introduce new problem, the development further of limit fibre Transmission system.Intermode dispersion and loss from early stage Limit, GVD finally limits, nonlinear fiber by now and dispersion comprehensively limit, carrying with transfer rate The high growth with transmission range, fibre-optic transmission system (FOTS) problems faced is also constantly changing.

In Large Copacity fiber optic transmission system long haul, multi-span cascades, and multichannel is simultaneously deposited, and optical fiber interaction length adds Greatly, make the accumulation of ASE noise, dispersion and nonlinear effect more serious, limit the property of Large Copacity long distance optic transmission system Energy.In recent years, many researchers are had both at home and abroad to the dispersion in Large Copacity long distance optic transmission system and nonlinear effect And its compensation method studied, it is concentrated mainly on and analyzes impact in fibre-optic transmission system (FOTS) for each nonlinear effect, mutually Between impact and nonlinear impairments compensation method.

Current nonlinear impairments compensation method mainly includes two classes：Optical domain compensation and electrical domain compensation.Collect with extensive Become developing so that being possibly realized to the dispersion of system and nonlinear compensation, not only flexibility is stronger of circuit using DSP technology, And cost is relatively low so that business practicality is possibly realized.In electrical domain compensation, the most commonly used is reverse transfer algorithm, by mould Intend the reverse digital transmission link of optical signal, to reach and to eliminate the suffered dispersion in transmitting procedure of optical signal and non-linear shadow The purpose rung.DBP algorithm needs first the nonlinear noise in channel to be estimated and predict, the method commonly used at present is sometimes Domain Gaussian noise model (GN model) and frequency domain logarithm perturbation model (FRLP model) etc..But due to answering of DBP algorithm Miscellaneous degree, compensation effect is not good.

Content of the invention

The purpose of the embodiment of the present invention is to provide a kind of structure of the channel compensation wave filter based on the related adaptation of carrier wave Method and apparatus and interchannel nonlinear noise suppressing method and system, realize carrying out dynamic compensation to nonlinear noise, thus Effectively reduce the bit error rate of channel, improve systematic function.Concrete technical scheme is as follows：

In a first aspect, the embodiment of the invention discloses the construction method of wave filter, comprising the steps：

S1) transmitting terminal send checking sequence, data-signal after MZ modulators modulate through being multiplexed into fiber channel, Through demultiplexing and coherent reception, obtain coherent detection data-signal after the transmission of M span；

S2) reverse virtual fiber link is set up according to the principle of " first-in last-out ", to coherent detection data using DBP algorithm Signal carries out dispersion compensation and nonlinear compensation, adds optical attenuator optical signal is decayed before each span compensates；

S3) repeat the above steps S1) and S2), obtain the different interference impact coefficients to destination channel for the channel, including from phase The influence of noise coefficient that impact coefficient, Cross-phase Modulation to signal for the position modulation leads to；

S4) interfere the impact coefficient to destination channel for the channel using different, obtain difference and interfere channel that destination channel is made The XPM phase noise becoming and its variance；

S5) using the different XPM phase noises interfering channel that destination channel is caused and its variance, different interference letters are obtained The auto-correlation coefficient of the XPM phase noise to destination channel for the road；

S6) using the different auto-correlation coefficients interfering the XPM phase noise to destination channel for the channel, obtain different frequency The impact size to central channel XPM effect for the channel；

S7) utilize the impact size to central channel XPM effect for the channel of different frequency, obtain and channel spacing and interference The related channel compensation wave filter based on the related adaptation of carrier wave of channel transmitting sequence.

Further, step S4) in, described it is expressed as based on the channel compensation wave filter of the related adaptation of carrier wave：

Wherein,For the different XPM phase noises interfering channel that destination channel is caused, ω_k-ω_sFor channel spacing, {b₀For interfering channel transmitting sequence, L is transmission range, γ is nonlinear factor, β₂For 2nd order chromatic dispersion parameter.

Further, described step S11) in, fiber channel is built using the symmetrical split-step fast Fourier transformed method of fixed step size Mould, step-length is h, and in step-length h, linear operator and nonlinear operator are separate, and each span carries out n times compensation, passes altogether Defeated M span, is followed by image intensifer in each span and optical signal is amplified.

Further, described step S2) in, described nonlinear compensation is carried out in each span centre position, for compensate Wave filter is：

Further, described step S2) in, described dispersion compensation adopts frequency domain filter, and the wave filter for compensating represents For：

Wherein, λ-carrier wavelength, ω-carrier frequency, S- chromatic dispersion gradient, the c- light velocity.

Further, in described nonlinear compensation, the optical signal of each channel adopts XPM module to calculate the intersection of other channels The impact to this channel for the phase-modulation, the computing formula of the XPM module of wherein q-th channel is：

Wherein, E_outOutput light field.

Second aspect, the embodiment of the invention discloses the construction device of wave filter, including：

Coherent detection signal acquisition module, sends checking sequence for transmitting terminal, data-signal is through MZ modulators modulate Afterwards through being multiplexed into fiber channel, obtain coherent detection data after the transmission of M span through demultiplexing and coherent reception Signal；

Coherent detection signal compensation module, reversely virtual for being set up according to the principle of " first-in last-out " using DBP algorithm Optical fiber link, carries out dispersion compensation and nonlinear compensation to coherent detection data-signal, adds light decay before each span compensates Subtract device optical signal is decayed；

DSP processing module, for by described coherent detection signal acquisition module and coherent detection signal compensation module Repeatedly process, obtain different interfere the impact coefficients to destination channel for the channel, including the impact coefficient to signal for the Self-phase modulation, The influence of noise coefficient that Cross-phase Modulation leads to；

XPM phase noise acquisition module, for interfering the impact coefficient to destination channel for the channel using different, obtains different XPM phase noise and its variance that interference channel causes to destination channel；

XPM auto-correlation coefficient acquisition module, for using the different XPM phase noises interfering channel that destination channel is caused And its variance, obtain the different auto-correlation coefficients interfering the XPM phase noise to destination channel for the channel；

The different XPM effect acquisition modules interfering channel, for interfering the XPM phase place to destination channel for the channel using different The auto-correlation coefficient of noise, obtains the impact size to central channel XPM effect for the channel of different frequency；

Channel compensation wave filter acquisition module, for the impact to central channel XPM effect for the channel using different frequency Size obtains the channel compensation wave filter based on carrier wave related adaptation related to channel spacing and interference channel transmitting sequence.

The third aspect, the embodiment of the invention discloses nonlinear noise suppressing method, including：

Using DBP algorithm, reverse virtual fiber link is set up according to the principle of " first-in last-out "；

In reverse virtual fiber link, to coherent detection data-signal using the channel compensation based on the related adaptation of carrier wave Wave filter calculates the XPM phase noise compensation value under different channels；

According to the XPM phase noise compensation value under different channels, the XPM phase noise in destination channel is compensated.

Further, described based on the channel compensation wave filter of the related adaptation of carrier wave it is：

Wherein,For the different XPM phase noises interfering channel that destination channel is caused, ω_k-ω_sFor channel spacing, {b₀For interfering channel transmitting sequence, L is transmission range, γ is nonlinear factor, β₂For 2nd order chromatic dispersion parameter.

Fourth aspect, the embodiment of the invention discloses nonlinear noise suppression system, including：

Reversely virtual fiber link establishment module, for being set up reversely according to the principle of " first-in last-out " using DBP algorithm Virtual fiber link；

XPM phase noise compensation computing module, for adopting to coherent detection data-signal in reverse virtual fiber link With the XPM phase noise compensation value under different channels is calculated based on the channel compensation wave filter of the related adaptation of carrier wave；

XPM phase noise compensation module, for according to the XPM phase noise compensation value under different channels, to destination channel In XPM phase noise compensate.

As seen from the above technical solutions, the embodiment of the present invention receives to the symbol of destination channel in receiving terminal, obtains To uncompensated sequence { r_k, by { r_kObtainValue, big to center channel effect according to the channel under different frequency The little structure channel compensation wave filter based on carrier wave related adaptation related to channel spacing and interference channel transmitting sequence, to light In fine channel model, the power of different channels carries out dynamically distributes, and is made an uproar to non-linear according to the principle of digit reverse transmission algorithm Sound compensates, and due to not needing to calculate all interference non-linear effects to central channel for the channel, therefore can effectively reduce The complexity of existing DSP backoff algorithm.

Brief description

In order to be illustrated more clearly that the embodiment of the present invention or technical scheme of the prior art, below will be to embodiment or existing Have technology description in required use accompanying drawing be briefly described it should be apparent that, drawings in the following description be only this Some embodiments of invention, for those of ordinary skill in the art, on the premise of not paying creative work, acceptable Other accompanying drawings are obtained according to these accompanying drawings.

Fig. 1 is the Large Copacity long-distance WDM optical transmission system structural representation 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 handling process schematic diagram in embodiment of the present invention wdm system；

Fig. 4 is that the utilization of the embodiment of the present invention is docked based on the interchannel nonlinear noise suppressing method of the related adaptation of carrier wave The collection of letters number carries out a handling process schematic diagram for nonlinear compensation；

Fig. 5 is that the different of the embodiment of the present invention interfere the curve synoptic diagram to center channel non-linearity effects for the channel；

Fig. 6 is the frequency characteristic schematic diagram of the wave filter being obtained according to Fig. 5 of the embodiment of the present invention；

Fig. 7 is the positive transmission schematic diagram in fiber channel for each span of the embodiment of the present invention；

Fig. 8 is each span of the embodiment of the present invention using reverse transfer schematic diagram in the virtual fiber link of DBP algorithm.

Specific embodiment

Below in conjunction with the accompanying drawing in the embodiment of the present invention, the technical scheme in the embodiment of the present invention is carried out clear, complete Site preparation description is it is clear that described embodiment is only a part of embodiment of the present invention, rather than whole embodiments.It is based on Embodiment in the present invention, it is every other that those of ordinary skill in the art are obtained under the premise of not making creative work Embodiment, broadly falls into the scope of protection of the invention.

First below the function used in the embodiment of the present invention and its parameter are done with an explanation：

E (z, t)-light field becomes envelope slowly；

E_inInput light field；

E_outOutput 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 light velocity；

Δa_k- in the z=L moment, the signal receiving is affected by nonlinear effect；

L transmission range；

S_h,u,m- characterize the size to phase noise contribution for the Self-phase modulation (SPM)；

X_h,u,m- characterize the size to phase noise contribution for the Cross-phase Modulation (XPM)；

The XPM phase noise that θ-interference channel causes to destination channel；

- phase noise variance；

R_k,s(l)-different auto-correlation functions with central channel for the phase noise interfering channel；

ω_k-ω_s- channel spacing.

The present invention is directed to distance Large Copacity WDM fiber Transmission system, using digit reverse transmission algorithm (DBP), checks colors Dissipate and carry out hybrid compensation with non-linear.Whole Transmission system is as shown in figure 1, fiber channel modeling is 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 method of wave filter, comprise the steps：

S1) transmitting terminal send checking sequence, data-signal after MZ modulators modulate through being multiplexed into fiber channel, Through demultiplexing and coherent reception, obtain coherent detection data-signal after the transmission of M span；

S2) reverse virtual fiber link is set up according to the principle of " first-in last-out ", to coherent detection data using DBP algorithm Signal carries out dispersion compensation and nonlinear compensation, adds optical attenuator optical signal is decayed before each span compensates；Often One span DBP algorithm block diagram is as shown in Figure 8.

S3) repeat the above steps S1) and S2), obtain the different interference impact coefficients to destination channel for the channel, including from phase The influence of noise coefficient that impact coefficient, Cross-phase Modulation to signal for the position modulation leads to；

S4) interfere the impact coefficient to destination channel for the channel using different, obtain difference and interfere channel that destination channel is made The XPM phase noise becoming and its variance；

S5) using the different XPM phase noises interfering channel that destination channel is caused and its variance, different interference letters are obtained The auto-correlation coefficient of the XPM phase noise to destination channel for the road；

S6) using the different auto-correlation coefficients interfering the XPM phase noise to destination channel for the channel, obtained according to principle of stacking Different frequency the impact size to central channel XPM effect for the channel；

S7) utilize the impact size to central channel XPM effect for the channel of different frequency, obtain and channel spacing and interference The related channel compensation wave filter based on the related adaptation of carrier wave of channel transmitting sequence.

Further, described step S11) in, fiber channel adopts symmetrical step Fourier (SSF) algorithm of fixed step size to enter Row modeling (as shown in Figure 2), in step-length h, linear operatorAnd nonlinear operatorSeparate.Wherein α is optical fiber loss factor, β₂It is fibre-optical dispersion constant, β₃It is second order GVD Slope, γ is nonlinear factor, and A (z, t) is optical field envelope.Assume that each span length is L_span, n times benefit is carried out to span Repay, then compensate times N=L_span/ h, each span is followed by image intensifer and optical signal is amplified, and transmits M span altogether, that is, always Conveying length is L=M × L_span.Each span transmission block diagram is as shown in Figure 7.

Further, described step S2) in, in described nonlinear compensation, the optical signal of each channel adopts XPM module to calculate The impact to this channel for the Cross-phase Modulation of other channels, the computing formula of the XPM module of wherein q-th channel is：

Wherein, E_outFor output light field.

Further, described step S2) in, using symmetrical split-step fast Fourier transformed method, described nonlinear compensation is in each span Centre position is carried out, and the wave filter for compensating is：

It should be noted that step S2) in nonlinear impairments penalty function wave filter be used for eliminating image intensifer and bring Spontaneous radiation (ASE) noise, application window function metht designs this wave filter, the bandwidth of suppression signal, limits high frequency noise components, When window function is chosen as Gaussian, expression formula is as follows：

Wherein, f_cIt is the centre frequency of wave filter, B is the three dB bandwidth of wave filter, m is filter order.Appropriate selection So that it is on the premise of bandwidth meets the requirements, side lobe attenuation is larger, to realize effectively filtering for the three dB bandwidth parameter of this wave filter Purpose except noise.

Further, described step S2) in, described dispersion compensation adopts frequency domain filter, and the wave filter for compensating represents For：

Further, step S4) in, described it is expressed as based on the channel compensation wave filter of the related adaptation of carrier wave：

Wherein,For the different XPM phase noises interfering channel that destination channel is caused, ω_k-ω_sFor channel spacing, {b₀For interfering channel transmitting sequence, L is transmission range, γ is nonlinear factor, β₂For 2nd order chromatic dispersion parameter.

It should be noted that step S4)-S7) concrete grammar as follows：

Send one section of checking sequence { a in transmitting terminal destination channel_k, interfere channel transmitting sequence { b_k, according to time-domain analysis Model, the zeroth order solution of transmission signal is represented by：

Wherein, g⁽⁰⁾(z, t)=Ψ (z) g (0, t),G (0, t) there is 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)

In receiving terminal through matched filtering, u⁽⁰⁾(L, t) does not contribute to nonlinear phase noise, u⁽¹⁾(L, t) to non-thread The contribution of property noise is represented by：

Formula (3) is updated in formula (5), can obtain：

Wherein, S_h,k,mRepresent the impact to signal for the Self-phase modulation, X_h,k,mRepresent the noise that Cross-phase Modulation leads to.

Work as h=0, can get the non-linear phase noise causing during u=m, be shown below：

Wherein,For phase noise, variance is：

It should be noted that the condition that the present invention only considers big dispersion accumulated value and do not embed dispersion compensation, at this Under part, X_0,m,mCan use and be expressed as：

The variance that therefore can get phase noise is：

The auto-correlation function of phase noise is：

Wherein, [u]⁺=max { u, 0 }

This formula represents the channel of the different frequency impact size to central channel XPM effect, when interfering channel distance center When channel is remote enough, it is negligible to the non-linear effects of central channel.

Embodiment 2

The embodiment of the invention discloses the construction device of the wave filter of method using embodiment 1, including：

Coherent detection signal acquisition module, sends checking sequence for transmitting terminal, data-signal is through MZ modulators modulate Afterwards through being multiplexed into fiber channel, obtain coherent detection data after the transmission of M span through demultiplexing and coherent reception Signal；

Coherent detection signal compensation module, reversely virtual for being set up according to the principle of " first-in last-out " using DBP algorithm Optical fiber link, carries out dispersion compensation and nonlinear compensation to coherent detection data-signal, adds light decay before each span compensates Subtract device optical signal is decayed；

DSP processing module, for by described coherent detection signal acquisition module and coherent detection signal compensation module Repeatedly process, obtain different interfere the impact coefficients to destination channel for the channel, including the impact coefficient to signal for the Self-phase modulation, The influence of noise coefficient that Cross-phase Modulation leads to.

XPM phase noise acquisition module, for interfering the impact coefficient to destination channel for the channel using different, obtains different XPM phase noise and its variance that interference channel causes to destination channel；

XPM auto-correlation coefficient acquisition module, for using the different XPM phase noises interfering channel that destination channel is caused And its variance, obtain the different auto-correlation coefficients interfering the XPM phase noise to destination channel for the channel；

The different XPM effect acquisition modules interfering channel, for interfering the XPM phase place to destination channel for the channel using different The auto-correlation coefficient of noise, obtains the impact size to central channel XPM effect for the channel of different frequency；

Channel compensation wave filter acquisition module, for the impact to central channel XPM effect for the channel using different frequency Size obtains the channel compensation wave filter based on carrier wave related adaptation related to channel spacing and interference channel transmitting sequence.

Embodiment 3

The embodiment of the invention discloses the nonlinear noise suppressing method of the construction method of wave filter using embodiment 1, Including：

Using DBP algorithm, reverse virtual fiber link is set up according to the principle of " first-in last-out ", coherent detection data is believed Number employing calculates the XPM phase noise compensation value under different channels based on the channel compensation wave filter of the related adaptation of carrier wave, to mesh XPM phase noise in mark channel compensates.

Further, described based on the channel compensation wave filter of the related adaptation of carrier wave it is：

Wherein,For the different XPM phase noises interfering channel that destination channel is caused, ω_k-ω_sFor channel spacing, {b₀For interfering channel transmitting sequence, L is transmission range, γ is nonlinear factor, β₂For 2nd order chromatic dispersion parameter.

Specifically, before carrying out optical signal transmission, first send one section of checking sequence, obtain different interference channels to center The impact coefficient of channel, using the interchannel nonlinear noise rejects trap R- based on the related adaptation of carrier wave for this coefficients to construct Filter, carries out nonlinear compensation using this wave filter to the signal receiving, calculation process as shown in Figure 4, in big dispersion Accumulate, do not have in the optical fiber link of dispersion management, when the modulation format of transmission signal is 16QAM, obtain R_θThe influence curve of (l) As shown in figure 5, in figure abscissa represents normalized channel spacing (such as after the nearest interference channel normalization of destination channel Channel spacing be 1)；Ordinate represents weight coefficient, that is, the interference channel representing different channels interval is to destination channel non-thread The size of property influence of noise；In legend, discrete point represents the variance of phase place, and straight line represents and obtains using after quadratic fit Weight coefficient.The frequency characteristic of filter frequencies R-filter being obtained according to this curve is as shown in fig. 6, in figure abscissa table Show carrier wavelength, ordinate represents normalization amplitude.Curve in Fig. 5 represents different interference channels to center channel non-linearity The size of effects, has power selectability wave filter according to this curve construction, nonlinear noise is compensated, by figure Understand, when interference channel distance center channel is remote enough, interfere the impact of interchannel noise to be negligible, therefore in error The complexity of DBP algorithm can be greatly reduced in the range of permission.

Embodiment 4

The embodiment of the invention discloses the nonlinear noise suppression system of the method using embodiment 3, including：

Reversely virtual fiber link establishment module, for being set up reversely according to the principle of " first-in last-out " using DBP algorithm Virtual fiber link；

XPM phase noise compensation computing module, for adopting to coherent detection data-signal in reverse virtual fiber link With the XPM phase noise compensation value under different channels is calculated based on the channel compensation wave filter of the related adaptation of carrier wave；

XPM phase noise compensation module, for according to the XPM phase noise compensation value under different channels, to destination channel In XPM phase noise compensate.

Embodiment 5

Multichannel dispersion non-linearity hybrid compensation algorithm specifically should in distance Large Copacity WDM fiber Transmission system As follows with process：

S1, transmitting terminal adopt 16QAM to modulate, and symbol mapping mode maps for Gray code, and Pulse shaped filter is chosen as Gaussian pulse, meets following relational expression：

, through being multiplexed into fiber channel after MZ modulators modulate, channel model is using symmetrical point for S2, data-signal Step fourier algorithm, enters DSP processing module after the transmission of M span through demultiplexing and coherent reception.

S3, DSP processing module using digit reverse transmission algorithm to the dispersion of signal and non-linear carry out hybrid compensation, Reverse virtual fiber link is set up according to the principle of " first-in last-out ", adds optical attenuator before each span compensates to optical signal Decayed.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 calculates the impact to this channel of the Cross-phase Modulation of other channels through XPM module.

S4, the compensation effect for further optimized algorithm, before carrying out optical signal transmission, first send one section of inspection sequence Row, obtain the different channels interfered the impact coefficient to central channel for the channel, be adapted to based on carrier wave correlation using this coefficients to construct Between nonlinear noise rejects trap R-filter, using this wave filter, nonlinear compensation is carried out to the signal receiving, calculate Flow process as shown in Figure 4, big dispersion accumulation, there is no dispersion management optical fiber link in, the modulation format of transmission signal is During 16QAM, obtain R_k,sL the influence curve of () is as shown in figure 5, the frequency of filter frequencies R-filter being obtained according to this curve Rate characteristic is as shown in Figure 6.

According to above-described embodiment, in receiving terminal, the symbol of destination channel is received, obtain uncompensated sequence {r_k, by { r_kObtain R_k,sL the value of (), has frequency according to the channel under different frequency to the big little structure of center channel effect The wave filter of selection function, carries out dynamically distributes to the power of different channels in fiber channel model, and is passed according to digit reverse The principle of defeated algorithm compensates to nonlinear noise, non-linear to central channel due to not needing to calculate all interference channels Impact, therefore can effectively reduce the complexity of backoff algorithm.

It should be noted that herein, such as first and second or the like relational terms are used merely to a reality Body or operation are made a distinction with another entity or operation, and not necessarily require or imply these entities or deposit between operating In any this actual relation or order.And, term " inclusion ", "comprising" or its any other variant are intended to Comprising of nonexcludability, wants so that including a series of process of key elements, method, article or equipment and not only including those Element, but also include other key elements being not expressly set out, or also include for this process, method, article or equipment Intrinsic key element.In the absence of more restrictions, the key element that limited by sentence "including a ..." it is not excluded that Also there is other identical element including in the process of described key element, method, article or equipment.

Each embodiment in this specification is all described by the way of related, identical similar portion between each embodiment Divide mutually referring to what each embodiment stressed is the difference with other embodiment.Real especially for system For applying example, because it is substantially similar to embodiment of the method, so description is fairly simple, referring to embodiment of the method in place of correlation Part illustrate.

The foregoing is only presently preferred embodiments of the present invention, be not intended to limit protection scope of the present invention.All Any modification, equivalent substitution and improvement made within the spirit and principles in the present invention etc., are all contained in protection scope of the present invention Interior.

Claims (10)

1. the construction method of wave filter is it is characterised in that comprise the steps：

S1) transmitting terminal send checking sequence, data-signal after MZ modulators modulate through being multiplexed into fiber channel, in warp Cross after M span is transmitted through demultiplexing and coherent reception, obtain coherent detection data-signal；

S2) reverse virtual fiber link is set up according to the principle of " first-in last-out ", to coherent detection data-signal using DBP algorithm Carry out dispersion compensation and nonlinear compensation, add optical attenuator before each span compensates and optical signal is decayed；

S3) repeat the above steps S1) and S2), obtain the different interference impact coefficients to destination channel for the channel, adjust including from phase place The influence of noise coefficient that impact coefficient, Cross-phase Modulation to signal for the system leads to；

S4) interfere the impact coefficient to destination channel for the channel using different, obtain difference and interfere channel that destination channel is caused XPM phase noise and its variance；

S5) using the different XPM phase noises interfering channel that destination channel is caused and its variance, different interference channels pair are obtained The auto-correlation coefficient of the XPM phase noise of destination channel；

S6) using the different auto-correlation coefficients interfering the XPM phase noise to destination channel for the channel, obtain the channel of different frequency Impact size to central channel XPM effect；

S7) utilize the impact size to central channel XPM effect for the channel of different frequency, obtain and channel spacing and interference channel The related channel compensation wave filter based on the related adaptation of carrier wave of transmitting sequence.

2. method according to claim 1 is it is characterised in that step S4) in, the described channel based on the related adaptation of carrier wave Compensating filter is expressed as：

$\begin{array}{c}{R}_{k,s}\left(l\right)={\mathrm{\&Delta;\&theta;}}_{k,s}^2{\&lsqb;1-\frac{\left|l\right|T}{\left|{\mathrm{\&beta;}}_2({\mathrm{\&omega;}}_k-{\mathrm{\&omega;}}_s)\right|L}\&rsqb;}^{+}\\ =(<{\left|b_0\right|}^4>-<{\left|b_0\right|}^2{>}^2)\frac{4\mathrm{\&gamma;}L}{\left|{\mathrm{\&beta;}}_2({\mathrm{\&omega;}}_k-{\mathrm{\&omega;}}_s)\right|T}{\&lsqb;1-\frac{\left|l\right|T}{\left|{\mathrm{\&beta;}}_2({\mathrm{\&omega;}}_k-{\mathrm{\&omega;}}_s)\right|L}\&rsqb;}^{+}\end{array}$

Wherein,For the different XPM phase noises interfering channel that destination channel is caused, ω_k-ω_sFor channel spacing, { b₀} For interfering channel transmitting sequence, L is transmission range, and γ is nonlinear factor, β₂For 2nd order chromatic dispersion parameter.

3. method according to claim 1 is it is characterised in that described step S1) in, fiber channel adopts fixed step size Symmetrical split-step fast Fourier transformed method is modeled, and step-length is h, and in step-length h, linear operator and nonlinear operator are separate, often One span carries out n times compensation, transmits M span altogether, is followed by image intensifer in each span and optical signal is amplified.

4. method according to claim 1 is it is characterised in that described step S2) in, described nonlinear compensation each across Section centre position is carried out, and the wave filter for compensating is：

$E_{BP}(z,t)=\exp (-h\frac{\hat{D}}{2})\exp (-h\hat{N})\exp (-h\frac{\hat{D}}{2})E_{BP}(z+h,t).$

5. method according to claim 1 is it is characterised in that described step S2) in, described dispersion compensation adopts frequency domain to filter Ripple device, the wave filter for compensating is expressed as：

$H\left(\mathrm{\&omega;}\right)=\exp \&lsqb;(\frac{{\mathrm{i\&lambda;}}^2}{4\mathrm{\&pi;}c}{\mathrm{D\&omega;}}^2+\frac{i}{6}\frac{{\mathrm{\&lambda;}}^2}{{\left(2\mathrm{\&pi;}c\right)}^2}({\mathrm{\&lambda;}}^{2}S+2\mathrm{\&lambda;}D\left){\mathrm{\&omega;}}^3\right)h\&rsqb;$

Wherein, λ-carrier wavelength, ω-carrier frequency, S- chromatic dispersion gradient, the c- light velocity.

6. method according to claim 1 is it is characterised in that in described nonlinear compensation, the optical signal of each channel is adopted Calculate the impact to this channel of the Cross-phase Modulation of other channels, the meter of the XPM module of wherein q-th channel with XPM module Calculating formula is：

$E_{out}=2\underset{q=1}{\overset{N}{\mathrm{\&Sigma;}}}{\left|{\hat{E}}_q\right|}^2-{\left|{\hat{E}}_q\right|}^2,$

Wherein, E_outOutput light field.

7. adopt the construction device of the wave filter of method described in claim 1 it is characterised in that including：

Coherent detection signal acquisition module, sends checking sequence, data-signal warp after MZ modulators modulate for transmitting terminal Cross and be multiplexed into fiber channel, obtain coherent detection data letter after the transmission of M span through demultiplexing and coherent reception Number；

Coherent detection signal compensation module, for setting up reverse virtual fiber using DBP algorithm according to the principle of " first-in last-out " Link, carries out dispersion compensation and nonlinear compensation to coherent detection data-signal, adds optical attenuator before each span compensates Optical signal is decayed；

DSP processing module, for multiple by described coherent detection signal acquisition module and coherent detection signal compensation module Process, obtain different interfering the impact coefficients to destination channel for the channel, including the impact coefficient to signal for the Self-phase modulation, intersection The influence of noise coefficient that phase-modulation leads to；

XPM phase noise acquisition module, for interfering the impact coefficient to destination channel for the channel using different, obtains different the interference XPM phase noise and its variance that channel causes to destination channel；

XPM auto-correlation coefficient acquisition module, for using the different XPM phase noises interfering channels that destination channel is caused and its Variance, obtains the different auto-correlation coefficients interfering the XPM phase noise to destination channel for the channel；

The different XPM effect acquisition modules interfering channel, for interfering the XPM phase noise to destination channel for the channel using different Auto-correlation coefficient, obtain the impact size to central channel XPM effect for the channel of different frequency；

Channel compensation wave filter acquisition module, for the impact size to central channel XPM effect for the channel using different frequency Obtain the channel compensation wave filter based on carrier wave related adaptation related to channel spacing and interference channel transmitting sequence.

8. adopt the nonlinear noise suppressing method of the wave filter described in claim 1 it is characterised in that including：

Using DBP algorithm, reverse virtual fiber link is set up according to the principle of " first-in last-out "；

In reverse virtual fiber link, to coherent detection data-signal using the channel compensation filtering based on the related adaptation of carrier wave Device calculates the XPM phase noise compensation value under different channels；

According to the XPM phase noise compensation value under different channels, the XPM phase noise in destination channel is compensated.

9. method according to claim 8 is it is characterised in that the described channel compensation wave filter based on the related adaptation of carrier wave For：

$\begin{array}{c}{R}_{k,s}\left(l\right)={\mathrm{\&Delta;\&theta;}}_{k,s}^2{\&lsqb;1-\frac{\left|l\right|T}{\left|{\mathrm{\&beta;}}_2({\mathrm{\&omega;}}_k-{\mathrm{\&omega;}}_s)\right|L}\&rsqb;}^{+}\\ =(<{\left|b_0\right|}^4>-<{\left|b_0\right|}^2{>}^2)\frac{4\mathrm{\&gamma;}L}{\left|{\mathrm{\&beta;}}_2({\mathrm{\&omega;}}_k-{\mathrm{\&omega;}}_s)\right|T}{\&lsqb;1-\frac{\left|l\right|T}{\left|{\mathrm{\&beta;}}_2({\mathrm{\&omega;}}_k-{\mathrm{\&omega;}}_s)\right|L}\&rsqb;}^{+}\end{array}$

Wherein,For the different XPM phase noises interfering channel that destination channel is caused, ω_k-ω_sFor channel spacing, { b₀} For interfering channel transmitting sequence, L is transmission range, and γ is nonlinear factor, β₂For 2nd order chromatic dispersion parameter.

10. adopt the nonlinear noise suppression system of the method for claim 8 it is characterised in that including：

Reversely virtual fiber link establishment module, reversely virtual for being set up according to the principle of " first-in last-out " using DBP algorithm Optical fiber link；

XPM phase noise compensation computing module, for adopting base to coherent detection data-signal in reverse virtual fiber link Channel compensation wave filter in the related adaptation of carrier wave calculates the XPM phase noise compensation value under different channels；

XPM phase noise compensation module, for according to the XPM phase noise compensation value under different channels, in destination channel XPM phase noise compensates.