WO2012106882A1

WO2012106882A1 - De-skew method, apparatus and optical communication system receiver

Info

Publication number: WO2012106882A1
Application number: PCT/CN2011/077071
Authority: WO
Inventors: 万文通
Original assignee: 华为技术有限公司
Priority date: 2011-07-12
Filing date: 2011-07-12
Publication date: 2012-08-16
Also published as: CN102318241B; CN102318241A

Abstract

An embodiment of the present invention provided a de-skew method, apparatus and optical communication system receiver. The method comprises: obtaining the amplitudes of each channel of signals obtained after coherent mixing and photoelectric conversion; combining each channel of signals into sets of twos and obtaining a fitting graph in the same coordinate system according to the amplitudes of the two channels of signals in each combination respectively; determining the skew between the two channels of signals in each combination according to the difference, slope value and the change of slope value trends of the fitting graph, the difference is the difference of the longitudinal coordinates corresponding to the same horizontal coordinate or the difference of the horizontal coordinates corresponding to the same longitudinal coordinate in the fitting graph, the slope value is the slope of each point with respect to the origin of the coordinate on the fitting graph; performing skew compensation for each channel of signals according to the skew between the two channels of signals in each combination. The de-skew method, apparatus and the optical communication system receiver provided in the embodiments of the present invention ensure the normal operation of the optical communication system and improve the performance of the optical communication system.

Description

De-delay method, device and optical communication system receiver

Technical field

The present invention relates to the field of communications technologies, and in particular, to a de-delay method, apparatus, and optical communication system receiver. Background technique

Optical coherence technology is a large-capacity and high-rate data transmission technology in the field of optical fiber communication. At the receiving end of the optical fiber communication system, the received signal light is interfering with the light emitted by the local oscillator by the coherent technique of the optical signal, and the multi-channel signal light is photoelectrically converted and then enters the electric system for signal processing. Since the multi-path signal light obtained after interference mixing is located in different path paths, and different path delays exist in different path paths, different path delays may affect the performance of the optical communication system, for example: The bit error rate of an optical communication system, etc.

In the prior art, a training data sequence of a specific format is added to a transmitting end of an optical communication system, and a receiving end of the optical communication system compares the received training data sequence with a known training data sequence to obtain a delay between each path. Then, the delay elimination processing is performed in the subsequent signal demodulation processing section. The prior art mainly deals with the delay between the polarization states, and cannot eliminate the delay between the signals of the same polarization state, thereby affecting the normal operation of the system or deteriorating the performance of the system. Summary of the invention

Embodiments of the present invention provide a de-delay method, apparatus, and optical communication system receiver to solve the problem that the prior art affects normal operation of the system and system performance degradation.

The embodiment of the invention provides a de-delay method, including:

Obtaining the amplitude of each signal obtained after coherent mixing and photoelectric conversion;

Combining the signals of the two signals into two, and respectively obtaining a fitting pattern in the same coordinate system according to the amplitudes of the two signals in each combination; Determining a delay between two signals in each combination according to a difference value of the fitting graph, a slope value, and a trend of a slope value, wherein the difference is an ordinate corresponding to the same abscissa in the fitted graph a difference between the difference or the abscissa corresponding to the same ordinate, the slope value being a slope of a relative coordinate origin of each point on the fitted graph;

Delaying compensation is performed on the respective signals according to delays between the two signals in the respective combinations.

The embodiment of the invention further provides a de-delay device, comprising:

An obtaining unit, configured to obtain amplitudes of respective signals obtained after coherent mixing and photoelectric conversion; a fitting unit configured to combine the signals of the respective signals according to the amplitudes of the two signals in each combination, Get a fitted graph in the same coordinate system;

a determining unit, configured to determine a delay between two signals in each combination according to a difference value, a slope value, and a trend of a slope value of the fitting graph, where the difference is the same horizontal direction in the fitting graph a difference between the ordinates corresponding to the coordinates or a difference between the abscissas corresponding to the same ordinate, the slope value being a slope of a relative coordinate origin of each point on the fitted graph;

The delay compensation unit is configured to perform delay compensation on the respective signals according to delays between the two signals in the respective combinations.

An embodiment of the present invention further provides an optical communication system receiver, including: a mixing device, a signal processing device, and a de-delay device;

The mixing device is configured to: perform coherent mixing and photoelectric conversion on the received optical signal and the local oscillating signal;

The de-delay device is configured to: acquire amplitudes of respective signals obtained after coherent mixing and photoelectric conversion; and combine the signals of the respective signals according to the amplitudes of the two signals in each combination, in the same Obtaining a fitting graph in the coordinate system; determining a delay between the two signals in each combination according to the difference value, the slope value, and the trend of the slope value of the fitting graph, wherein the difference is the fitting graph The difference between the ordinate of the same abscissa or the abscissa corresponding to the same ordinate, the slope value is the slope of the relative coordinate origin of each point on the fitted graph; according to the two signals in the respective combinations Delay between the delays of each of the signals;

The signal processing device is configured to: process each signal output by the de-delay device. The de-delay method, the device and the optical communication system receiver provided by the embodiments of the present invention combine the signals obtained by photoelectric conversion into two, and obtain a fitting graph according to the amplitudes of the two signals in each combination, and then according to the simulation The difference between the graph, the slope value and the slope value change, determine the delay between the two signals in each combination, and delay compensation for each signal, thus ensuring the normal operation of the optical communication system and improving the light. The performance of the communication system. DRAWINGS

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the embodiments or the description of the prior art will be briefly described below. Obviously, the drawings in the following description are only It is a certain embodiment of the present invention, and other drawings can be obtained from those skilled in the art without any creative work.

1 is a schematic structural view of a mixing device in a receiver of an existing optical communication system;

2 is a flow chart of an embodiment of a de-delay method provided by the present invention;

Figure 3a is a schematic diagram of a signal pattern of 0*pi phase delay between any two signals; Figure 3b is a schematic diagram of a signal pattern of 0.1*pi phase delay between any two signals; Figure 3c is any two signals FIG. 3d is a schematic diagram of a signal pattern with a phase delay of 1*pi between any two signals; FIG. 4 is a schematic diagram of another embodiment of the de-delay method provided by the present invention; Flow chart

Figure 5a is a schematic diagram of a signal pattern of 0.1*pi phase delay between any two signals; Figure 5b is a schematic diagram of a signal pattern of 0.2*pi phase delay between any two signals; Figure 5c is any two signals Schematic diagram of signal pattern with 0.3*pi phase delay; Figure 5d is a schematic diagram of signal pattern with 0.4*pi phase delay between any two signals; Figure 5e is 0.5*pi phase delay between any two signals Schematic diagram of the signal pattern; Figure 5f is a schematic diagram of the signal pattern of 0.6*pi phase delay between any two signals; Figure 5g is a schematic diagram of a signal pattern of 0.7*pi phase delay between any two signals; Figure 5h is a schematic diagram of a signal pattern of 0.8*pi phase delay between any two signals; Figure 5i is any two signals FIG. 6 is a flow chart of another embodiment of a de-delay method provided by the present invention;

7 is a schematic structural diagram of an embodiment of a de-delay device according to the present invention;

FIG. 8 is a schematic structural diagram of still another embodiment of a de-delay device according to the present invention; FIG.

FIG. 9 is a schematic structural diagram of an embodiment of an optical communication system receiver according to the present invention; FIG. 10 is a schematic structural diagram of a signal processing apparatus in a receiver of an existing optical communication system. detailed description

The technical solutions in the embodiments of the present invention are clearly and completely described in the following with reference to the accompanying drawings in the embodiments of the present invention. It is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative efforts are within the scope of the present invention.

1 is a schematic structural diagram of a mixing device in a receiver of an existing optical communication system. As shown in FIG. 1, since the communication system finally uses an electrical signal as a demodulated signal, the receiving end needs to perform a signal through a mixing operation. The light S is demodulated on the light and then photoelectrically converted into an electrical signal.

The mixing device separates the received signal light S from the light LO emitted by the local laser into an orthogonal X polarization state and a y polarization state by a polarization beam splitter. The X-polarization state of the signal light S and the X-polarization state of the light LO enter a 90-degree optical mixer for interference mixing, and the y-polarization state of the signal light S and the y-polarization state of the light LO enter a 90-degree optical mixer for interference mixing. The eight optical signals output after interference mixing are: Sx+jLOx, Sx+-jl_Ox, Sx+LOx, Sx-LOx, Sy+jLOy, Sy-jLOy, Sy+LOy, Sy-Loy, where, the angle x Indicates the x-polarization state and y represents the y-polarization state. After the eight optical signals are photoelectrically converted by four pairs of balanced photodiodes, four electric signals xi, xq, yi and yq are obtained, and the four electric signals are respectively processed by the amplification and automatic gain control unit to obtain four electric signals. For: Xi, Xq, Yi, and Yq. The de-delay method provided by the embodiment of the invention can perform delay processing on the four-way electrical signals Xi, Xq, Yi and Yq obtained after interference mixing and photoelectric conversion.

FIG. 2 is a flowchart of an embodiment of a de-delay method according to the present invention. As shown in FIG. 2, the method includes:

S201. Acquire amplitudes of respective signals obtained after coherent mixing and photoelectric conversion;

The four-way electrical signals Xi, Xq, Yi, and Yq obtained after coherent mixing and photoelectric conversion are analog signals. Therefore, an analog-to-digital converter (ADC) device can be used, and the analog signal Xi can be used. Xq, Yi, and Yq are sampled to obtain the amplitudes of the four digital signals, which are represented by XI, XQ, YI, and YQ, respectively.

It should be noted that, in the process of acquiring the amplitude of each signal, there may be that the amplitude of the corresponding signal cannot be temporarily collected due to the fact that the X-polarization state or the y-polarization state temporarily does not distribute the signal light S, which may be intermittent. Sex occurs, but usually takes a short time or even disappears within a few seconds. In this case, you can wait until the signal amplitude is acquired.

S202. Combine the signals of the two signals into two, and obtain a fitting pattern in the same coordinate system according to the amplitudes of the two signals in each combination.

The fitting graph obtained in the same coordinate system involved in the embodiment of the present invention may specifically be a fitting function obtained in the same coordinate system or a graph of a fitting function.

As a possible implementation manner, in S102, one of the signals may be used as the first reference signal, for example, XI is the first reference signal, and the remaining signals (XQ, YI, and YQ) are respectively associated with the first signal. The reference signal (XI) is combined.

As another feasible implementation manner, in S102, two signals of the same polarization state in each signal may be combined to obtain an X polarization state combination (XI and XQ) and a y polarization state combination (YI and YQ), and Combining one signal in each of two different polarization states results in a combination of xy polarization states (eg, combining XI and YI;).

For each combination, the process of fitting the figure in the same coordinate system according to the amplitude of the two signals in each combination, taking the combination of XI and XQ as an example: XI and XQ can be collected at a certain time. The amplitude is taken as a point (XI1, XQ1) on the two-dimensional coordinate plane, and 1 represents the time point of the acquisition, where the abscissa is the amplitude of one signal and the ordinate is the amplitude of the other signal. Thus, the amplitudes of XI and XQ collected over a period of time correspond to a set of points (Xln, XQn) on the coordinate plane, and the subscript n can be an integer such as 1, 2, 3, .... Represents the point in time of collection. Further, the two signals can be fitted at various points on the same coordinate system to obtain a fitted graph. Wherein, according to the point set fitting to obtain the fitting graph, various existing fitting methods may be used, and details are not described herein again.

Alternatively, the amplitudes of XI and XQ collected over a period of time may be corresponding to a set of points (Xln, XQn) on the coordinate plane to obtain a fitting curve equation, that is, a combination of XI and XQ signals is obtained. The function equation, according to which the equation can be drawn in the coordinate system.

If the signal light S is a polarization multiplexed modulated light, the present invention needs to modulate the same data for the X polarization state and the y polarization state of the signal light S, then XI = XQ = YI = YQ. If the signal light S is a single-polarized signal light, after passing through the polarization beam splitter and the 90-degree optical mixer, the same information is distributed in the X-polarization state and the y-polarization state, and in general, the X-polarization There is a certain difference in the power magnitude of the signal corresponding to the state and the y-polarization state, then XI=XQ=k*YI=k*YQ, where k is a constant greater than or equal to zero, and the magnitude of k is distributed by the signal light S to the mixer The optical power of the internal X-polarization state and the y-polarization state is determined.

It can be seen that the hardware device has the same influence on the signal output after interference mixing, for example: the photoelectric conversion effect is consistent, and the amplifier in the amplification and automatic gain control unit (for example: Transimpedance Amplifer (TIA)) has the same linearity. The magnification of the automatic gain control (AGC) unit in the amplification and automatic gain control unit is the same, whether the signal light S is a polarization multiplexed modulated light or a single polarized state signal light, XI, XQ, YI The signal envelope shape of YQ and YQ are the same, that is, if the signal light S is polarization-multiplexed modulated light, and the same data is modulated in two polarization states of X and y, the signal envelopes of XI, XQ, YI and YQ The shape and the amplitude of the same size are the same on the time axis; if it is the single polarization state signal S, the signal envelopes of XI, XQ, YI and YQ have the same shape, but the X polarization state and the y polarization State The magnitude of the signal at the same time may not be equal).

Therefore, if you combine XI, XQ, YI, and YQ, the resulting fit is usually a straight line, an ellipse, or a circle.

S203. Determine a delay between two signals in each combination according to a difference value, a slope value, and a trend of a slope value of the fitting graph, where the difference is corresponding to the same abscissa in the fitting graph. a difference between the ordinates or a difference between the abscissas corresponding to the same ordinate, the slope value being a slope of a relative coordinate origin of each point on the fitted graph;

The four-channel signals XI, XQ, YI and YQ of the X-polarization and y-polarization outputs in the common homodyne demodulation system in communication are illustrated. Other systems, such as heterodyne systems, are similar, assuming: XI ^ A _XI - cos(wt ^ φ _χι ) ■> XQ = A _XQ - sin(wt + φ _χΰ + 0.5 * pi) , YI = Α _ΥΙ - cos(wt + φ _ΥΙ ) ^ ! ^二^^ ^^^ + ^^10. Among them, Α _ΧΙ , A _XQ , Α _ΥΙ are the amplitudes of the XI, XQ, Yl, YQ signals, ie amplitude, φ _ΧΙ , p _XQ , φ _γπ , respectively, modulation of XI, XQ, Yl, YQ signals The phase is the optical frequency and t is the time. Due to the principle of quadrature modulation, a phase difference of 0.5*pi is added to the modulated data, so a phase value of 0.5*pi is attached to XQ and YQ in the above expression. In the case where the signal S is a polarization multiplexed light and the same data is modulated on the X polarization state and the y polarization state, or if the signal S is a single polarization, if XI, XQ, YI and YQ have the same modulation Phase, ie <P _XI = (P _XQ HQ , and

XQ = A _XQ · sin(wt + φ _χΰ + 0.5 * pi) = A _XQ · cos(wt + φ _χΰ ) , YQ = A _YQ - sin(wt + φ _γς} + 0.5 * pi) = A _YQ · cos (wt + φ _Υβ ) , since there is no inherent phase difference of 0.5*pi between XI and YI, XI=XQ=k1 *YI=k2*YQ, .

, (A / A _YI ) , k1 , k2 are constants. It can be seen from the above analysis that the output signals after coherent mixing have the characteristics of the cosine signal, so the cosine function can be used to represent the amplitude waveform of each signal.

Assume that the electrical signal obtained by photoelectric conversion of the above optical signal is expressed as:

XI = Κ _Ή ·

, Υρ =

, for 4 channels of photoelectrically converted electrical signals, where K _XI , K _XQ , K _YI , K _YQ For the amplitude of the 4 signals, "for the angular frequency of each signal, since the output data of each signal is consistent, the angular frequency is the same, ^, ^, , ^ is the phase value of each signal (reacting the signals of each channel) Delay case).

If the coherent mixing receiving system has the same delay value for each signal, ie ⁼ e

Then XI=XQ=YI=YQ. Taking the combination of XI and XQ as an example, the fitted graph shown in Fig. 3a can be fitted, and Fig. 3a is a schematic diagram of the fitting graph with 0*pi phase delay between the two signals. Wherein, pi is pi; when ^ ^^ ι * ^, obtained by combining the XI and XQ pattern shown fitted to Figure _3b, Figure _3b is, independently is 0.1 * pi phase delay between the two signals shown in Fitting the graphical diagram of the graph; when ^β ^· ⁵ * ^, then the combination of XI and XQ yields the fitted graph shown in Figure 3c, and Figure 3c shows the phase delay of 0.5*pi between any two signals. Fit the graphical diagram; when ^^ ¹ * ^, then XI and XQ combine to obtain the fitted graph shown in Figure 3d, and Figure 3d shows the fitting of 1 * pi phase delay between any two signals. Graphical diagram.

It can be seen from Fig. 3a - Fig. 3d that the difference between the two points on the same abscissa in the graph of the fitting function can reflect the ellipticity of the graph, and the slope values of the two points are in accordance with the horizontal The trend of changes in coordinates can reflect the changing trend of the ellipse. When the phase difference between the two signals is 0, the pattern obtained by fitting the amplitudes of the two signals is a straight line, as shown in Fig. 3a; as the phase difference between the two signals increases, the two paths The pattern obtained by fitting the signal amplitude gradually becomes elliptical. When the phase difference between the two signals reaches 0.5*pi, that is, 90 degrees, the pattern composed of the two signals becomes circular; when the phase difference of the two signals is at 0.5 *Between pi-1*pi, the pattern obtained by fitting the amplitude of the two signals is again elliptical from the circle, until the phase difference between the two signals is 1*pi, the two signals are composed. The graph becomes a straight line again, as shown in Figure 3d.

The difference of the fitting figure involved in the embodiment of the present invention means that the minimum amplitude of the acquired two signals is the origin, and within the range of the abscissa of the fitting figure, in any abscissa, corresponding Fit the difference between the ordinates of two points in the graph. If a horizontal coordinate corresponds to only one point, that is, only one ordinate, then the difference between the ordinates is considered to be zero. Understandably, the difference between the fitted figures can also Refers to the minimum amplitude of the two signals collected as the origin, within the range of the ordinate of the fitted graph, in any ordinate, the difference between the abscissas of the two points in the corresponding fitted graph, if The ordinate only corresponds to one point, that is, only one abscissa, and the difference between the abscissas is considered to be zero. The slope value refers to the slope of the relative coordinates of the points on the top of the fitted graph. The trend of the slope value is that, from the origin, as the abscissa increases, the slope of the points on the graph relative to the origin changes. It can be seen that the difference in the fitted graph, the slope value, and the trend of the slope value reflect the delay between the two signals. Therefore, the delay value between the two paths can be estimated by fitting the difference in the graph, the slope value, and the trend of the slope value. It should be noted that the change trend of the difference value, the slope value, and the slope value given in the embodiment of the present invention is only the basic feature item of the fitting graph of the two-way signal or the corresponding function of the fitting function. It can be understood that Based on the basic feature terms of the difference value, the slope value, and the slope value of the fitted graph, determining the delay value between the two signals in each combination may also be based on the fitting pattern of the two signals or Some other feature items in the graph corresponding to the fitting function are used to assist in determining the delay value between the two signals.

S204. Perform delay compensation on each of the signals according to a delay between the two signals in each combination.

Specifically, if one of the signals in the S102 is the first reference signal and the remaining signals are respectively combined with the first reference signal, the delay between the remaining signals and the first reference signal may be respectively determined in S104. Delay compensation for the remaining signals.

If two signals of the same polarization state in each signal are combined in S102, a combination of X polarization states (X XQ ) and y polarization states (丫1 and 丫0) is obtained, and each of the two different polarization states is taken. The signal combination results in a combination of xy polarization states (eg, XI and YI). In S104, in the xy polarization state combination, one of the signals is the second reference signal (eg, XI), and the X polarization including the second reference signal. In a combination of states or y-polarization states (ie, in a combination of XI and XQ containing XI), the other signal (ie, XQ) in the combination is extended according to the delay between the two signals in the combination. Time compensation; in the y-polarization combination or the X-polarization combination that does not include the second reference signal (ie, the YI and YQ combinations that do not include XI), based on the delay between the two signals in the combination (YI and YQ) The delay between the two signals in the combination of xy polarization states (XI and YI), delay compensation for the two signals in the combination.

The de-delay method provided in this embodiment obtains a fitting graph according to the amplitudes of the two signals in each combination by combining the signals obtained by photoelectric conversion, and further, according to the difference and the slope value of the fitting graph. And the trend of the slope value changes, determine the delay between the two signals in each combination, and delay compensation for each signal, thereby ensuring the normal operation of the optical communication system and improving the performance of the optical communication system.

FIG. 4 is a flowchart of still another embodiment of the de-delay method according to the present invention. As shown in FIG. 4, in this embodiment, one of the signals is used as the first reference signal, and the signals in the respective signals are used. The remaining signals are combined with the first reference signal, respectively. The method includes:

S401, performing analog-to-digital conversion on each of the signals obtained after coherent mixing and photoelectric conversion; since the four electrical signals obtained after coherent mixing and photoelectric conversion are analog signals, analog-to-digital conversion can be performed on the analog signals. Get 4 digital signals.

5402. Down-sampling each channel of the analog-to-digital conversion to obtain the amplitude of each signal; and obtaining a digital signal sequence after analog-to-digital conversion, since the sampling frequency of the analog-to-digital conversion is high, after the analog-to-digital conversion The distribution of the digital signals in the resulting digital signal sequence is dense, which affects the speed at which the graphics are fitted. The digital signal sequence obtained after the analog-to-digital conversion can be further down-sampled. The downsampling refers to: taking a value of several sampling points separated by the analog-to-digital conversion interval, that is, removing the partial sampling obtained after the analog-to-digital conversion. Points, for example: The value can be taken every other sampling point, so that half of the sampling points can be removed, thereby reducing the amount of data processed and improving the system signal processing speed.

5403. Combine two signals of the same polarization state in each signal to obtain a combination of an X polarization state and a y polarization state, and combine a signal combination in each of two different polarization states to obtain a combination of xy polarization states; specifically, Combining two signals XI and XQ of the polarization state to obtain a combination of X polarization states; The two signals YI and YQ of the y-polarization state are combined to obtain a y-polarization state combination. A combination of signals is obtained in each of the x-polarization state and the y-polarization state to obtain a combination of xy polarization states. As a preferred embodiment, XI and YI may be combined, or XQ and YQ may be combined.

5404. The amplitudes of the two signals in each combination obtained in the same time are drawn in the same coordinate system, where the abscissa of the coordinate system is the amplitude of one signal, and the ordinate is the amplitude of the other signal;

5405. Fitting a point drawn in the coordinate system over a period of time to obtain a fitted graph; for a combination of XI and XQ, the magnitudes of XI and XQ acquired at a certain time may be taken as a two-dimensional coordinate plane. One point (XI1, XQ1), 1 indicates the time point of the acquisition, where the abscissa is the amplitude of one signal and the ordinate is the amplitude of the other signal. Thus, the amplitudes of XI and XQ collected over a period of time correspond to a set of points (Xln, XQn) on the coordinate plane, and the subscript n can be an integer such as 1, 2, 3, .... Represents the point in time of collection. Further, the two signals can be fitted at various points on the same coordinate system to obtain a fitted graph. Similarly, for the combination of YI and YQ, the amplitudes of YI and YQ collected over a period of time correspond to a set of points (Yin, YQn) on the coordinate plane, and the set of points (Yin, YQn) is fitted. , get the fitted graph. Taking the case where the xy polarization states are combined into XI and YI as an example, the amplitudes of XI and YI collected over a period of time correspond to a set of points (Xln, Yin) on the coordinate plane, and a set of points (Xln, Yin ) Fits to get a fitted graph.

Wherein, according to the point set fitting to obtain the fitting graph, various existing fitting methods can be used.

5406. Find a corresponding delay value in the delay compensation table according to the difference value, the slope value, and the trend of the slope value of the fitted graph.

In this embodiment, the delay value corresponding to the difference value of the various fitting patterns, the slope value, and the trend of the slope value change may be calculated in advance, and a delay compensation table is established, where the delay compensation table includes the amplitude of the two signals. The value of the difference, the slope value, and the delay value corresponding to the trend of the slope value. This embodiment provides a delay compensation table as follows: Difference Slope value Slope value change trend Delay value

Equal to zero does not care not change 0*pi Large ordinate value on the same abscissa

The slope value of that point along with the abscissa value

The maximum inclination obtained under different abscissas is 0. l*pi

Decreased not to increase by zero, smaller ordinate value

The rate is in the range of 0. 7-1 (corresponding to Figure 5a)

The slope value of that point along with the abscissa value

Increase the strength and increase the strength

Large ordinate value on the same abscissa

The slope value of that point along with the abscissa value

The maximum inclination obtained under different abscissas is 0. 2*pi

Decreased not to increase by zero, smaller ordinate value

The ratio is in the range of 0. 6-0. 7 (corresponding to Figure 5b)

The slope value of that point along with the abscissa value

Increase the strength and increase the strength

Large ordinate value on the same abscissa

The slope value of that point along with the abscissa value

The maximum inclination obtained under different abscissas is 0.3**pi

Decreased not to increase by zero, smaller ordinate value

The rate is in the range of 0. 53-0. 6 (corresponding to Figure 5c)

The slope value of that point along with the abscissa value

Increase the strength and increase the strength

Large ordinate value on the same abscissa

The slope value of that point along with the abscissa value

The maximum inclination obtained under different abscissas is 0. 4*pi

Decreased not to increase by zero, smaller ordinate value

The rate is in the range of 0. 51-0. 53 (corresponding to Figure 5d)

The slope value of that point along with the abscissa value

Increase the strength and increase the strength

The maximum inclination obtained under different abscissas is 0. 5*pi

Not equal to zero

The rate is equal to 0.5 (corresponding to Figure 5e)

Large ordinate on the same abscissa

The slope value and the ordinate of the maximum oblique corresponding point obtained under different abscissas are smaller. 0. 6*pi

Not equal to zero

The value of the value is in the range of 0. 51-0. 53. The slope value of the corresponding point of the value is traversed (corresponding to Figure 5f).

Decrease in the increase of the value

Large ordinate on the same abscissa

The slope value and the ordinate of the maximum oblique corresponding point obtained under different abscissas are smaller. 0. 7*pi

Not equal to zero

The value of the value is in the range of 0. 53-0. 6 The slope value of the corresponding point of the value is traversed (corresponding to Figure 5g)

Decrease in the increase of the value

Large ordinate on the same abscissa

The slope of the corresponding point obtained from the different abscissas is smaller and the ordinate is smaller. 0. 8*pi

Not equal to zero

The value of the value is in the range of 0. 6-0. 7 The slope value of the corresponding point of the value is traversed (corresponding to Figure 5h)

Decrease in the increase of the value

Large ordinate on the same abscissa

The maximum slope corresponding to the different slopes is the slope value and the ordinate is smaller. 0. 9*pi

Not equal to zero

The rate value is in the range of 0. 7-1. The slope value of the corresponding point of the value is traversed (corresponding to Figure 5i).

Decrease in the increase of the value

Equal to zero, do not care, do not change, l*pi, according to the corresponding relationship between the trend of the fitted graph difference, the slope value and the slope value and the delay value, the difference between the fitted graphs obtained from the two signals, The trend of the slope value and the slope value is used to find the corresponding delay value.

This embodiment only gives a form of the delay compensation table. It can be understood that the more the interval division in the delay compensation table, the more accurate the delay compensation.

S407, in the xy polarization state combination, one of the signals is the second reference signal; In the combination of the X polarization state or the y polarization state including the second reference signal, delay compensation is performed on the other signal in the combination according to the delay between the two signals in the combination; In the combination of the y-polarization state or the X-polarization state of the second reference signal, according to the delay between the two signals in the combination and the delay between the two signals in the combination of the xy polarization states, in the combination The two signals are delayed for compensation.

Specifically, taking two signals in the xy polarization state combination as XI and YI as an example, assuming that XI is the second reference signal, then the second reference signal XI is the X polarization state combination, then the X polarization state combination XI In XQ, delay compensation of XQ can be directly performed according to the delay between XI and XQ; and for y polarization states YI and YQ which do not include the second reference signal XI, the delay between XI and YI can be used. For YI, delay compensation is required. For YQ, it is necessary to consider the delay between XI and YI and the delay between YI and YQ to compensate the delay of YQ.

FIG. 6 is a flowchart of another embodiment of a de-delay method according to the present invention. As shown in FIG. 6, in this embodiment, two signals of the same polarization state in each path signal are combined to obtain an X-polarization state combination and The y polarization states are combined, and each of the two different polarization states is combined to obtain a combination of xy polarization states. The method includes:

S601, performing analog-to-digital conversion on each signal obtained after coherent mixing and photoelectric conversion;

5602. Down-sampling the signals of the analog-to-digital conversion to obtain the amplitudes of the signals. For the specific processes of S601 and S602, refer to the related descriptions of S401 and S402.

S603, wherein one of the signals is used as a first reference signal, and the remaining ones of the signals are combined with the first reference signal.

Taking the XI signal in each signal as the first reference signal as an example, a combination of XI and XQ, a combination of XI and YI, and XI and YQ can be combined.

5604. The amplitudes of the two signals in each combination obtained in the same time are plotted in the same coordinate system, the abscissa of the coordinate system is the amplitude of one signal, and the ordinate is the amplitude of the other signal; S605, Fitting a point drawn in the coordinate system over a period of time to obtain a fitted pattern;

S606. According to the difference value, the slope value, and the slope value change trend of the fitted graph, Find the corresponding delay value in the delay compensation table.

The process of S604-S606 can be referred to the related description of S404-S406.

S607. Perform delay compensation on the remaining signals according to a delay between the remaining signals and the first reference signal, respectively.

If XI is the first reference signal in S603, then in the process of S604-S606, the combination of XI and XQ, the combination of XI and YI, and the delay of the two signals in the combination of XI and YQ can be respectively obtained, so that they can be respectively XQ, YI and YQ perform delay compensation.

A person skilled in the art can understand that all or part of the process of implementing the above embodiment method can be completed by a computer program to instruct related hardware, and the program can be stored in a computer readable storage medium. In execution, the flow of an embodiment of the methods as described above may be included. The storage medium may be a magnetic disk, an optical disk, or a read-only storage memory.

(Read-Only Memory, ROM) or random access memory (RAM).

FIG. 7 is a schematic structural diagram of an embodiment of a de-delay apparatus according to the present invention. As shown in FIG. 7, the apparatus includes: an obtaining unit 11, a fitting unit 12, a determining unit 13 and a delay compensating unit 14; For obtaining the amplitudes of the signals obtained after the coherent mixing and photoelectric conversion; the fitting unit 12 is configured to combine the signals of the two signals according to the amplitudes of the two signals in each combination, A fitted graph is obtained in the same coordinate system;

a determining unit 13 , configured to determine a delay between two signals in each combination according to a difference value, a slope value, and a trend of a slope value of the fitting graph, where the difference is the same in the fitting graph a difference between the ordinates corresponding to the abscissa or a difference between the abscissas corresponding to the same ordinate, the slope value being a slope of a relative coordinate origin of each point on the fitted graph;

The delay compensation unit 14 is configured to perform delay compensation on the respective signals according to delays between the two signals in the respective combinations.

Specifically, after acquiring the amplitude of each channel signal by the acquiring unit 11, the fitting unit 12 may specifically use one of the signals as the first reference signal and the remaining signals to be the first reference respectively. Combining the signals to obtain a fitting pattern of each combination; or, the fitting unit 12 may combine two signals of the same polarization state in each signal to obtain a combination of X polarization states (XI and XQ) and y polarization states ( YI and YQ), and combine a signal combination in each of two different polarization states to obtain a combination of xy polarization states (eg, combining XI and YI;). The determining unit 13 estimates the delay value between the two paths by fitting the difference in the graph, the slope value, and the trend of the slope value. If the fitting unit 12 combines one of the signals as the first reference signal and the remaining signals with the first reference signal, the delay compensation unit 14 can respectively extend the delay between the remaining signals and the first reference signal. Time delay compensation for the remaining signals. If the fitting unit 12 combines the two signals of the same polarization state in the respective signals, the combination of the X polarization states (XI and XQ) and the y polarization state (YI and YQ) are obtained, and each of the two different polarization states is taken. When a signal combination is combined to obtain an xy polarization state combination (for example, XI and YI), the delay compensation unit 14 may be in the xy polarization state combination, wherein one of the signals is the second reference signal (for example: XI), including the second reference. In the X-polarization combination or the y-polarization combination of the signal (ie, in the combination of XI and XQ including XI), according to the delay between the two signals in the combination, another signal (ie, XQ) in the combination is performed. Delay compensation; in a combination of y-polarization states or X-polarization states that do not include a second reference signal (ie, YI and YQ combinations that do not include XI), based on the delay between the two signals in the combination (YI and The delay between the YQs and the delay between the two signals in the combination of xy polarization states (1 and 丫1), delay compensation for the two signals in the combination.

FIG. 8 is a schematic structural diagram of still another embodiment of a de-delay apparatus according to the present invention. As shown in FIG. 8, the apparatus includes: an obtaining unit 11, a fitting unit 12, a determining unit 13, and a delay compensating unit 14;

The fitting unit 12 may include at least one module as follows:

The first combination module 121 is configured to use a signal of each of the signals as a first reference signal, and combine the remaining signals of the respective signals with the first reference signal;

The second combining module 122 combines two signals of the same polarization state in the respective signals to obtain a combination of an X polarization state and a y polarization state, and combines one signal combination in each of two different polarization states to obtain an xy polarization state combination. . Correspondingly, the delay compensation unit 14 may be specifically configured to: delay compensation of the remaining signals according to a delay between the remaining signals and the first reference signal respectively; or

In the xy polarization state combination, wherein one of the signals is the second reference signal; in the X polarization state combination or the y polarization state combination including the second reference signal, according to the combination between the two signals in the combination The delay of the other signal in the combination is delayed; in the y-polarization combination or the X-polarization combination not including the second reference signal, according to the delay between the two signals in the combination And a delay between the two signals in the combination of the xy polarization states, and delay compensation is performed on the two signals in the combination.

Further, the fitting unit 12 may further include:

The drawing module 123 is configured to draw the amplitudes of the two signals in each combination obtained in the same time in the same coordinate system, where the abscissa of the coordinate system is the amplitude of one signal, and the ordinate is the amplitude of the other signal. Value

A fitting module 124 is configured to fit points drawn in the coordinate system over a period of time to obtain a fitted graph.

The determining unit 13 may include:

The storage module 131 is configured to establish a delay compensation table, where the delay compensation table includes a magnitude difference, a slope value, and a delay value corresponding to a trend of the slope value of the two signals;

The searching module 132 is configured to search for a corresponding delay value in the delay compensation table according to the difference value, the slope value, and the slope value change trend of the fitted graph.

The delay compensation unit 14 may further include:

The output module 141 is configured to output the delay estimation values of the respective signals to the data buffer adjustment module corresponding to each channel signal;

The data buffer adjustment module 142 is configured to perform delay adjustment on the corresponding signal according to the delay value output by the output module.

The de-delay device provided by the embodiment of the present invention corresponds to the de-delay method provided by the embodiment of the present invention, and is an execution device of the de-delay method. Therefore, the de-delay device provided by the embodiment of the present invention, For the process of performing the de-delay method, refer to the method embodiment, and details are not described herein again. The de-delay device provided by the embodiment of the present invention combines the signals obtained by photoelectric conversion into two, and obtains a fitting graph according to the amplitudes of the two signals in each combination, and then according to the difference and the slope of the fitting graph. The value and the trend of the slope value change, determine the delay between the two signals in each combination, and delay compensation for each signal, thereby ensuring the normal operation of the optical communication system and improving the performance of the optical communication system.

FIG. 9 is a schematic structural diagram of an embodiment of an optical communication system receiver according to the present invention. As shown in FIG. 9, the optical communication system receiver includes: a mixing device 1, a signal processing device 2, and a de-delay device 3;

Mixing device 1 , configured to perform coherent mixing and photoelectric conversion on the received optical signal and the local oscillating signal;

The delay device 2 is configured to obtain the amplitudes of the signals obtained after the coherent mixing and photoelectric conversion; combining the signals of the respective signals according to the amplitudes of the two signals in each combination, at the same coordinate A fitting pattern is obtained in the system; determining a delay between two signals in each combination according to a difference value, a slope value, and a trend of a slope value of the fitting pattern, wherein the difference is in the fitting graph The difference between the ordinates corresponding to the same abscissa or the difference between the abscissas corresponding to the same ordinate, the slope value is the slope of the relative coordinate origin of each point on the fitted graph; according to the two signals in the respective combinations Delay between the delays of each of the signals;

The signal processing device 3 is configured to process each signal output by the de-delay device 2.

The specific structure of the mixing device 1 can be seen in FIG. 1 . The specific structure of the de-delay device 2 can be seen in FIG. 7 and FIG. 8 . The structure of the signal processing device 3 is as shown in FIG. 10 , including: dispersion compensation The module 31, the clock recovery module 32, the polarization mode dispersion (PMD) compensation module 33, and the carrier recovery module 34, the functions of these modules and the operations performed by the modules are prior art, and are not described herein again.

In the optical communication system receiver provided by the embodiment of the present invention, the mixing device 1 and the signal processing device

The specific operations performed by 3 are all prior art. The de-delay operation performed by the delay device 2 can be specifically See the de-delay embodiment and the de-delay device embodiment provided by the present invention, and details are not described herein again.

The receiver of the optical communication system provided by the embodiment of the present invention combines the signals obtained by the interference mixing and the photoelectric conversion, and obtains a fitting pattern according to the amplitude of the two signals in each combination, and then according to the fitting graph. The difference value, the slope value and the trend of the slope value determine the delay between the two signals in each combination, and delay compensation for each signal, thereby ensuring the normal operation of the optical communication system and improving the optical communication system. Performance.

The de-delay device provided by the embodiment of the invention can be integrated into a digital signal processing (DSP) chip or a Field-Programmable Gate Array (FPGA) chip for software. The implementation can be implemented by using an application specific integrated circuit (ASIC).

The de-delay device provided by the embodiment of the present invention may be separately provided, and may also be integrated in a device with an optical mixer, a PD tube, a TIA amplifier and the like in a mixing device of the receiver of the optical communication system.

It should be noted that the above embodiments are only for explaining the technical solutions of the present invention, and are not intended to be limiting; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those skilled in the art that: The technical solutions described in the foregoing embodiments are modified, or some of the technical features are equivalently replaced. The modifications and substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

Rights request

A de-delay method, characterized in that it comprises:

Combining the respective signals into two and two, respectively obtaining a fitting pattern in the same coordinate system according to the amplitudes of the two signals in each combination;

Determining a delay between two signals in each combination according to a difference value of the fitting graph, a slope value, and a trend of a slope value, wherein the difference is an ordinate corresponding to the same abscissa in the fitted graph a difference between the difference or the abscissa corresponding to the same ordinate, the slope value being a slope of a relative coordinate origin of each point on the fitted graph;

2. The method according to claim 1, wherein the combining the signals of the respective roads is specifically:

One of the signals is used as a first reference signal, and the remaining signals of the respective signals are combined with the first reference signal.

The method according to claim 2, wherein the delay compensation is performed on the signals according to the delay between the two signals in the respective combinations, specifically:

Delay compensation is performed on the remaining signals according to a delay between the remaining signals and the first reference signal, respectively.

The method according to claim 1, wherein the combining the signals of the respective roads is specifically:

The two signals of the same polarization state in the respective signals are combined to obtain a combination of an X polarization state and a y polarization state, and each of the two different polarization states is combined to obtain an xy polarization state combination.

The method according to claim 4, wherein the delay compensation is performed on the signals according to the delay between the two signals in the respective combinations, specifically:

In the xy polarization state combination, one of the signals is the second reference signal; In the combination of the X polarization state or the y polarization state including the second reference signal, delay compensation is performed on the other signal in the combination according to the delay between the two signals in the combination; In the combination of the y-polarization state or the X-polarization state of the second reference signal, according to the delay between the two signals in the combination and the delay between the two signals in the combination of the xy polarization states, in the combination The two signals are delayed for compensation.

The method according to any one of claims 1-5, wherein the fitting graph is obtained in the same coordinate system according to the amplitudes of the two signals in each combination, specifically:

The amplitudes of the two signals in each combination obtained in the same time are plotted in the same coordinate system, the abscissa of the coordinate system is the amplitude of one signal, and the ordinate is the amplitude of the other signal;

Fitting the points drawn in the coordinate system over a period of time yields a fitted pattern.

The method according to any one of claims 1-5, wherein before the obtaining the amplitudes of the signals obtained by the coherent mixing and the photoelectric conversion, the method further comprises:

A delay compensation table is established, wherein the delay compensation table includes a magnitude difference, a slope value, and a delay value corresponding to a trend of the slope value of the two signals.

The method according to claim 7, wherein the determining the delay between the two signals in each combination according to the difference value, the slope value, and the trend of the slope value of the fitting pattern, For:

A corresponding delay value is searched in the delay compensation table according to the difference value of the fitting pattern, the slope value, and the trend of the slope value.

The method according to any one of claims 1 to 5, wherein the obtaining the amplitudes of the signals obtained by the coherent mixing and the photoelectric conversion comprises:

Performing analog-to-digital conversion on each of the signals obtained after coherent mixing and photoelectric conversion;

The signals of the analog-to-digital conversion are down-sampled to obtain the amplitudes of the respective signals.

10. A de-delay device, comprising:

An acquiring unit, configured to obtain amplitudes of respective signals obtained after coherent mixing and photoelectric conversion; a fitting unit, configured to combine the signals of the respective signals by two signals according to two signals in each combination The magnitude of the figure, the fitted graph in the same coordinate system;

The de-delay device according to claim 10, wherein the fitting unit comprises at least one of the following modules:

a first combination module, wherein one of the signals is used as a first reference signal, and the remaining ones of the signals are combined with the first reference signal;

The second combination module combines two signals of the same polarization state in the respective signals to obtain a combination of an X-polarization state and a y-polarization state, and combines one signal combination in each of two different polarization states to obtain an xy polarization state combination.

The de-delay apparatus according to claim 11, wherein the delay compensation unit is specifically configured to: respectively: according to a delay between the remaining signal and the first reference signal, The remaining signals are compensated for delay; or

The de-delay device according to any one of claims 10 to 12, wherein the fitting unit further comprises:

a drawing module for plotting the amplitudes of two signals in each combination obtained in the same time In a coordinate system, the abscissa of the coordinate system is the amplitude of one signal, and the ordinate is the amplitude of the other signal;

A fitting module is configured to fit points drawn in the coordinate system over a period of time to obtain a fitted graph.

The de-delay device according to any one of claims 10 to 12, wherein the determining the compensation unit comprises:

a storage module, configured to establish a delay compensation table, where the delay compensation table includes a magnitude difference, a slope value, and a delay value corresponding to a trend of a slope value of the two signals;

And a searching module, configured to search for a corresponding delay value in the delay compensation table according to a difference value, a slope value, and a slope value change trend of the fitting graph.

The de-delay device according to claim 14, wherein the delay compensation unit comprises:

An output module, configured to output delay values of the respective signals to a data buffer adjustment module corresponding to each channel signal;

And a plurality of data buffer adjustment modules, configured to perform delay adjustment on the corresponding signals according to the delay values output by the output module.

The de-delay device according to any one of claims 10 to 12, wherein the obtaining unit comprises:

a plurality of analog-to-digital conversion modules for respectively performing analog-to-digital conversion on a signal obtained after coherent mixing and photoelectric conversion;

A plurality of downsampling modules are configured to respectively downsample a signal that has undergone analog-to-digital conversion to obtain a magnitude of a signal.

An optical communication system receiver, characterized by: a mixing device, a signal processing device, and the de-delay device according to any one of claims 10-16;

The mixing device is configured to: perform coherent mixing and photoelectric conversion on the received optical signal and the local oscillating signal; The de-delay device is configured to: acquire amplitudes of respective signals obtained after coherent mixing and photoelectric conversion; and combine the signals of the respective signals according to the amplitudes of the two signals in each combination, in the same Obtaining a fitting graph in the coordinate system; determining a delay between the two signals in each combination according to the difference value, the slope value, and the trend of the slope value of the fitting graph, wherein the difference is the fitting graph The difference between the ordinate of the same abscissa or the abscissa corresponding to the same ordinate, the slope value is the slope of the relative coordinate origin of each point on the fitted graph; according to the two signals in the respective combinations Delay between the delays of each of the signals;

The signal processing device is configured to: process each signal output by the de-delay device.