WO2017071257A1 - 一种监测光通信网络色散的方法及装置 - Google Patents

一种监测光通信网络色散的方法及装置 Download PDF

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WO2017071257A1
WO2017071257A1 PCT/CN2016/086577 CN2016086577W WO2017071257A1 WO 2017071257 A1 WO2017071257 A1 WO 2017071257A1 CN 2016086577 W CN2016086577 W CN 2016086577W WO 2017071257 A1 WO2017071257 A1 WO 2017071257A1
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signal
optical
optical signal
time domain
analog electrical
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PCT/CN2016/086577
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English (en)
French (fr)
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李朝晖
陈宇立
王大伟
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华为技术有限公司
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Priority to EP16858700.4A priority Critical patent/EP3361653B1/en
Publication of WO2017071257A1 publication Critical patent/WO2017071257A1/zh
Priority to US15/967,267 priority patent/US10263697B2/en

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
    • H04B10/07—Arrangements for monitoring or testing transmission systems; Arrangements for fault measurement of transmission systems
    • H04B10/075—Arrangements for monitoring or testing transmission systems; Arrangements for fault measurement of transmission systems using an in-service signal
    • H04B10/079—Arrangements for monitoring or testing transmission systems; Arrangements for fault measurement of transmission systems using an in-service signal using measurements of the data signal
    • H04B10/0795—Performance monitoring; Measurement of transmission parameters
    • H04B10/07951—Monitoring or measuring chromatic dispersion or PMD
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
    • H04B10/07—Arrangements for monitoring or testing transmission systems; Arrangements for fault measurement of transmission systems
    • H04B10/075—Arrangements for monitoring or testing transmission systems; Arrangements for fault measurement of transmission systems using an in-service signal
    • H04B10/077—Arrangements for monitoring or testing transmission systems; Arrangements for fault measurement of transmission systems using an in-service signal using a supervisory or additional signal
    • H04B10/0775—Performance monitoring and measurement of transmission parameters
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
    • H04B10/25—Arrangements specific to fibre transmission
    • H04B10/2507—Arrangements specific to fibre transmission for the reduction or elimination of distortion or dispersion
    • H04B10/2513—Arrangements specific to fibre transmission for the reduction or elimination of distortion or dispersion due to chromatic dispersion
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
    • H04B10/60—Receivers
    • H04B10/61—Coherent receivers
    • H04B10/616—Details of the electronic signal processing in coherent optical receivers
    • H04B10/6161—Compensation of chromatic dispersion

Definitions

  • the present invention relates to the field of communications technologies, and in particular, to a method and apparatus for monitoring chromatic dispersion of an optical communication network.
  • optical Performance Monitoring has attracted more attention with the development of optical fiber communication.
  • CD Chromatic Dispersion
  • optical dispersion is an important indicator for measuring the quality of fiber links, and is of great significance for estimation and measurement systems.
  • Light dispersion refers to the difference in transmission rate of each frequency component in a light wave. As shown in Figure 1, the optical signal is carried by different frequency components in the optical fiber. These different frequency components have different propagation speeds when passing through the same medium. This phenomenon is called dispersion.
  • dispersion In time, when the optical pulse propagates through the optical fiber, its waveform is broadened in time and causes distortion of the signal, causing reception errors and limiting the transmission capacity of the optical fiber.
  • the dispersion has a linear relationship with the length of the fiber, that is, the longer the fiber, the larger the dispersion.
  • the CD is monitored at an intermediate node transmitted by the fiber-optic communication system to determine the length of the fiber through which the optical signal passes, or, in the case of a known fiber length, the dispersion parameter of the fiber can be determined.
  • the method for measuring dispersion in the prior art may be a pulse delay method, and the specific implementation of the method may be (the implementation of the method is as shown in FIG. 2):
  • a pulse signal generator is used to modulate a laser, and the optical signal output from the laser is split into two paths through a beam splitter. All the way into the fiber under test (the optical pulse signal of this way is broadened due to dispersion). The other way, directly into the optical monitor and receiver without going through the fiber under test. Send the two received signals to the dual trace oscilloscope. The widths of the two light pulses are measured from the displayed pulse waveforms. It is assumed that the input fiber and the optical pulse waveform output from the fiber are both Gaussian, and the dispersion of the fiber can be calculated by measuring the pulse spread caused by the fiber transmission by the time domain method.
  • the pulse delay method is a method for directly determining the dispersion coefficient of a fiber by measuring the delay difference of a narrow optical pulse of different wavelengths transmitted through an optical fiber.
  • a narrow pulse of a known shape (usually a width of several hundred ps) is injected into the fiber to be tested. Due to the dispersion of the fiber, the light pulse will be broadened after transmission along the fiber, and the broadened light is recorded at the output end of the fiber.
  • Pulse waveform the difference between the output pulse width and the input pulse width, can be used to obtain the pulse broadening caused by dispersion, so that the dispersion of the fiber can be estimated according to the broadening.
  • the estimation of the dispersion by the method requires an original pulse alignment, which is difficult to implement in practical long-distance transmission applications.
  • the invention provides a method and a device for monitoring the dispersion of an optical communication network, and the method and device provided by the invention solve the problem that the existing pulse delay method is difficult to realize in a long-distance transmission application.
  • a method of monitoring dispersion of an optical communication network comprising:
  • the fiber dispersion in the transmission of the signal to be tested is obtained by the correspondence between the delay value and the dispersion.
  • obtaining the fiber dispersion in the transmission process of the signal to be tested by using the correspondence between the delay value and the dispersion includes:
  • ⁇ 0 is a delay value between the two time domain power signals
  • T is an equivalent baseband signal of the signal to be tested
  • the symbol width, ⁇ is the center frequency of the signal to be tested, and c is the speed of light.
  • the first analog electrical signal is converted into a corresponding first time domain power signal
  • Converting the second analog electrical signal to the second time domain power signal includes:
  • the optical signal is a signal including an X-polarized signal and a Y-polarized signal, wherein the X-polarized signal and the Y-polarized signal are orthogonal
  • the method includes:
  • the X-polarized signal and the Y-polarized signal are respectively coherently mixed with the first optical signal and the second optical signal as the signal to be tested, to obtain an X-polarized analog electrical signal Ux corresponding to the first optical signal, a Y-polarized analog electrical signal Uy corresponding to the first optical signal and an X-polarized analog electrical signal Lx corresponding to the second optical signal; and a Y-polarized analog electrical signal Ly corresponding to the second optical signal; wherein Ux and Lx are X-polarized signals respectively a signal obtained by coherent mixing with the first optical signal and the second optical signal; Uy and Ly are Y polarization states respectively coherent with the first optical signal and the second optical signal The signal obtained by mixing;
  • the first analog electrical signal includes the Ux and Uy
  • the second analog electrical signal includes the Lx and Ly.
  • an apparatus for monitoring dispersion of an optical communication network comprising:
  • An optical signal source configured to generate a first optical signal and a second optical signal; wherein a center frequency of the first optical signal and the second optical signal is on both sides of a center frequency of the signal to be tested, and the first light
  • the center frequency difference between the signal and the second optical signal is equal to the baud rate
  • the first coherent receiver is connected to the optical signal source, and is configured to coherently mix the signal to be tested with the first optical signal to obtain a first analog electrical signal;
  • the second coherent receiver is connected to the optical signal source, and configured to coherently mix the signal to be tested and the second optical signal to obtain a second analog electrical signal;
  • the signal processor being coupled to the first coherent receiver and the second coherent receiver for converting the first analog electrical signal into a corresponding first time domain power signal, Converting the two analog electrical signals into a second time domain power signal, and determining a delay value between the first time domain power signal and the second time domain power signal; and the correspondence between the delay value and the dispersion Obtaining fiber dispersion during transmission of the signal to be tested.
  • the optical signal source includes:
  • the optical signal source includes:
  • a laser source for generating an optical signal
  • An optoelectronic modulator and a microwave signal source the two inputs of the optoelectronic modulator being respectively coupled to the laser source and the output of the microwave signal source for utilizing a signal generated by the microwave signal source
  • the optical signal is subjected to carrier suppression modulation to generate the first optical signal and the second optical signal.
  • an apparatus for monitoring dispersion of an optical communication network comprising:
  • a coherent receiving module configured to coherently mix the signal to be tested and the first optical signal to obtain a first analog electrical signal; coherently mixing the signal to be tested and the second optical signal to obtain a second analog electrical signal;
  • a center frequency of the first optical signal and the second optical signal is on both sides of a center frequency of the signal to be tested, and a center frequency difference between the first optical signal and the second optical signal is equal to a baud rate;
  • a conversion module configured to convert the first analog electrical signal into a corresponding first time domain power signal, and convert the second analog electrical signal into a second time domain power signal
  • a delay value determining module configured to determine a delay value between the first time domain power signal and the second time domain power signal
  • a dispersion determining module configured to obtain, by using a correspondence between the delay value and the dispersion, fiber dispersion in the signal transmission process of the signal to be tested.
  • the chromatic dispersion determining module is specifically configured to use the delay value and the formula Determining a fiber dispersion in the transmission of the signal to be tested; wherein the ⁇ 0 is a delay value between the two time domain power signals, and the T is an equivalent baseband signal of the signal to be tested The symbol width, ⁇ is the center frequency of the signal to be tested, and c is the speed of light.
  • the conversion determining module is specifically configured to perform analog-to-digital conversion processing on the first analog electrical signal to obtain a first a digital signal; performing analog-to-digital conversion processing on the second analog electrical signal to obtain a second digital signal; and modulo square the value of each time of the first digital signal to obtain the first time domain power signal; The value of each time of the second digital signal is modulo squared to obtain the second time domain power signal.
  • the dispersion detecting method and device provided by the embodiments of the present invention perform coherent mixing of a signal to be tested and a specific optical signal to obtain two analog electrical signals of the upper and lower sidebands of the optical signal to be measured, and then pass between the two analog electrical signals.
  • the delay value determines the dispersion, so the scheme provided in this embodiment is independent of the modulation pattern and is related to the baud rate, so the algorithm is simple and easy to implement.
  • 1 is a schematic diagram of transmission of an optical signal in an optical fiber in the prior art
  • FIG. 2 is a schematic flow chart of a pulse delay method for measuring dispersion in the prior art
  • 3a and 3b are schematic diagrams of a transmission signal m1(t) in the prior art
  • 4a and 4b are schematic views of a signal m2(t) in the prior art
  • Figure 5 is a schematic diagram of a signal m3(t) in the prior art
  • Figure 6 is a schematic diagram of loading m1(f) and m2(f) onto a light wave
  • Figure 7 is a functional image of the cross-correlation of two signals with a time delay
  • FIG. 8 is a schematic diagram of signal processing of a method for monitoring chromatic dispersion of an optical communication network according to an embodiment of the present invention.
  • FIG. 9 is a schematic flowchart of a method for monitoring chromatic dispersion of an optical communication network according to an embodiment of the present invention.
  • FIG. 10 is a schematic diagram of signal processing for determining a delay value between two signals by cross-correlating two time domain power signals according to an embodiment of the present invention
  • FIG. 11 is a schematic diagram of signal processing for treating two polarization states of an optical signal to be detected as two independent signals according to an embodiment of the present invention
  • FIG. 12 is a schematic structural diagram of an apparatus for monitoring chromatic dispersion of an optical communication network according to an embodiment of the present invention.
  • FIG. 13 is a schematic structural diagram of an optical signal source according to an embodiment of the present disclosure.
  • FIG. 14 is a schematic structural diagram of another apparatus for monitoring chromatic dispersion of an optical communication network according to an embodiment of the present invention.
  • the time domain form of the optical signal transmitted from the transmitter can be expressed as:
  • the time domain form of the optical signal transmitted from the transmitter can be expressed as:
  • E S (t) ⁇ [ ⁇ n s n ⁇ (t-nT)]*p(t) ⁇ c(t) (where s n is signal bit data, ⁇ (t) is a pulse function, p(t ) is a pulse waveform, c(t) is the optical carrier, * is the convolution operation, and T is the symbol period of the signal.
  • m 1 (t) is the baseband form of the transmitted signal, which is represented by a pulse function of period T (as shown in Figure 3a), its frequency domain form is shown in Figure 3b, and m 1 (f) is a period of 1/ The periodic signal of T.
  • p(t) is a pulse waveform. If p(t) takes a non-return-to-zero rectangular wave, then m 2 (t) is as shown in Figure 4a: m 2 (t) corresponds to the frequency domain form m 2 (f) As shown in 4b, m 2 (t) is a band-limited signal with a bandwidth of 1/T of the main lobe;
  • m 3 (t) is an optical carrier, and since the optical carrier is a single carrier of frequency f 1 , it can be expressed as a pulse signal in the frequency domain (as shown in FIG. 5 );
  • the signal is transmitted by superimposing the transmitted signal on the optical carrier signal during transmission, it is:
  • m 1 (f) is a periodic signal with a period of 1/T
  • m 2 (f) is a symmetric band-limited signal with a bandwidth of 1/T of the main lobe.
  • the two are multiplied and then loaded onto the center frequency f 1 of the optical wave (eg Figure 6), within a finite bandwidth (f 1 -1/T to f 1 +1/T), according to Figure 6, only f 1 -1/2T and f 1 +1/2T can be exactly the same
  • the cycle repeats the signal.
  • the bandwidth is symmetrical about the center wavelength, so if no dispersion is added, the two narrowband signals at f 1 -1/2T and f 1 +1/2T obtained by the two coherent receivers should be identical. Therefore, the dispersion in the signal transmission can be detected by comparing the difference between the two narrowband signals at f 1 - 1/2T and f 1 + 1/2T.
  • the principle of dispersion measurement is that after the dispersion is added, the two narrowband signals at f 1 -1/2T and f 1 +1/2T which should be identical are received, and the delay is generated under the influence of dispersion, in the time domain. The two signals will be misaligned.
  • the two signals with time delay are cross-correlated, and the function image is shown in Fig. 7.
  • the image of the function has a sharp peak.
  • the position or abscissa of the peak indicates the number of sample points where the two signals are staggered.
  • the acquired upper and lower sidebands 1/2 (ie, f 1 -1/2T and f 1 +1/2T) time domain power signals, that is, two time domain data are cross-correlated, and a correlation function can be obtained, and the correlation function is obtained.
  • the abscissa of the peak refers to the delay that occurs when two dispersions of the same time domain data (the upper and lower sides have a 1/2 time domain power signal) after adding the dispersion, and this time delay is proportional to the added dispersion value.
  • the embodiment of the present invention provides a method for monitoring chromatic dispersion of an optical communication network (the method flow is shown in FIG. 9 , and the specific signal flow processing is shown in FIG. 8 ).
  • the method specifically includes:
  • Step 901 Coherently mixing the signal to be tested with the first optical signal to obtain a first analog electrical signal, and coherently mixing the signal to be tested with the second optical signal to obtain a second analog electrical signal.
  • a center frequency of an optical signal and the second optical signal is on both sides of a center frequency of the signal to be tested, and a center frequency difference between the first optical signal and the second optical signal is equal to a baud rate;
  • the measurement of the fiber dispersion can be achieved by the first optical signal and the second optical signal in the vicinity of the 1/2 baud rate of the center frequency of the signal to be tested.
  • a preferred embodiment of the first optical signal and the second optical signal is that a center frequency of the first optical signal is 1/2 baud rate of a center frequency of the signal to be tested, and a center frequency of the second optical signal is The center frequency of the signal to be tested is reduced by 1/2 baud.
  • Step 902 Convert the first analog electrical signal into a corresponding first time domain power signal, and convert the second analog electrical signal into a second time domain power signal.
  • the specific implementation of the conversion may be:
  • Step 903 Determine a delay value between the first time domain power signal and the second time domain power signal.
  • the time delay between the two time domain power signals can be determined in various ways after the analog electrical signal is converted into the time domain power signal.
  • the optimization is performed by two time domains.
  • the power signal is cross-correlated to determine the delay value between the two signals (the specific implementation principle is shown in Figure 10).
  • the correlation function of the two time power signals contains a spike, and the position of the peak ⁇ 0 represents the center frequency plus or minus two at the baud rate.
  • the delay value of the power signal (as shown in Figure 7), which is proportional to the magnitude of the dispersion.
  • the delay value means that the two analog electrical signals at the center frequency plus or minus 1/2 baud rate should repeat the same signal for the period when no dispersion is added.
  • the carrier frequencies of the two signals are different.
  • the dispersion is affected, so that the two signals are misaligned to produce a delay.
  • the added dispersion is proportional to the amount of delay, so the dispersion can be calculated from the delay value.
  • Step 904 Obtain a fiber dispersion in the transmission process of the signal to be tested by using a correspondence between the delay value and the dispersion.
  • the signal to be tested is input into two coherent receivers, and the two coherent receivers respectively mix the signal to be tested with the local laser 1 and the local oscillator laser 2 to obtain two analog electric signals, wherein two coherent receivers process the signals.
  • the flow is completely the same.
  • the following is an example of the signal processing flow of the coherent receiver corresponding to the local oscillator laser 1:
  • the signal to be tested and the local oscillator laser 1 are simultaneously input into the coherent receiver, and the coherent receiver mixes the signal to be tested with the local oscillator laser 1 and then obtains four optical signals; then, the four optical signals are divided into two groups of optical signals. Photoelectric detection is performed for each group of optical signals and then an analog electrical signal is obtained. Two sets of optical signals are correspondingly obtained by two analog electrical signals (each analog electrical signal represents information of a part of the final output analog electrical signal), and two analog electrical signals. The signal combination forms an analog electrical signal (ie, the first analog electrical signal in this embodiment) that is finally output by the coherent receiver;
  • the analog electrical signal is converted into a discrete digital electrical signal a (wherein the digital signal a is a signal corresponding to the frequency of the signal to be tested f-1/2T).
  • the local oscillator laser 2 and the signal to be tested can obtain a digital electrical signal b through the same processing process (wherein the digital signal b corresponds to the signal to be tested f+1) Signal at /2T frequency).
  • a signal processor (for example, a DSP) modulo squares the value of the digital electrical signal a at each time to obtain a first time domain power signal; and modulates the value of the digital electrical signal b at each moment to obtain a second time domain power signal (wherein , the time domain power signal represents the power of the digital electrical signal at each moment);
  • the fiber dispersion can be determined by the following formula:
  • ⁇ 0 is a delay value between the two time domain power signals
  • the T is a symbol width of an equivalent baseband signal of the signal to be tested
  • ⁇ is a center of the signal to be tested Frequency
  • c is the speed of light.
  • polarization multiplexing techniques modulate information into two orthogonal polarization states (ie, X polarization and Y polarization).
  • a polarization beam splitter PBS can be used to separate the signal to be measured and the local oscillator laser into two orthogonal polarization states for dispersion estimation.
  • the optical signal to be detected includes an X-polarized signal and a Y-polarized signal, wherein the X-polarized signal and the Y-polarized signal are orthogonal
  • the X-polarized signal and the Y-polarized signal may be respectively used as independent signals.
  • four analog electrical signals need to be combined to form two analog electrical signals, and the specific implementation may be:
  • the four analog electrical signals are: Ux, Lx, Uy, and Ly, specifically
  • the X-polarization signal is respectively coherently received with the first optical signal and the second optical signal to obtain a signal in an X-polarization direction, where the signal includes an X-polarized analog electrical signal Ux corresponding to the first optical signal, and a corresponding second optical signal.
  • the Y polarization state signal is coherently mixed with the first optical signal and the second optical signal to obtain a signal in a Y polarization direction, where the signal includes a Y polarization analog electrical signal Uy corresponding to the first optical signal and a corresponding second optical signal.
  • the Y-polarized analog electrical signal Ly is coherently mixed with the first optical signal and the second optical signal to obtain a signal in a Y polarization direction, where the signal includes a Y polarization analog electrical signal Uy corresponding to the first optical signal and a corresponding second optical signal.
  • the Y-polarized analog electrical signal Ly Ly.
  • the corresponding first analog electrical signal and second analog electrical signal respectively comprise two parts, specifically:
  • the first analog electrical signal includes the Ux and Uy
  • the second analog electrical signal includes the Lx and Ly.
  • determining the time domain power signal may be: modulating the squares of Ux and Uy respectively (ie,
  • the time delay value is obtained by cross-correlating the power signals of the two polarization states, the influence of the polarization mode dispersion can be eliminated. Because if the polarization mode dispersion also exists in the dispersion system, the polarization mode dispersion parameter does not affect the magnitude of
  • the signals of the two polarization states corresponding to the optical signal to be detected can be regarded as two independent signals, and then processed by coherent reception with the first optical signal and the second optical signal, respectively, to obtain two optical fibers.
  • Dispersion value (signal flow processing is shown in Figure 11).
  • the method provided by the embodiment of the invention is independent of the modulation pattern and is related to the baud rate, so the algorithm is simple and easy to implement;
  • the method provided by the embodiment of the present invention can accurately and effectively implement optical network CD monitoring, and provides a reliable information source for optical network management, thereby making optical network monitoring management and operation more convenient.
  • this example provides an apparatus for monitoring chromatic dispersion of an optical communication network, the apparatus comprising:
  • the optical signal source 1201 is configured to generate a first optical signal and a second optical signal, where a center frequency of the first optical signal and the second optical signal is on both sides of a center frequency of the signal to be tested, and the first The center frequency difference between the optical signal and the second optical signal is equal to the baud rate;
  • the first coherent receiver is connected to the optical signal source, and configured to coherently mix the signal to be tested with the first optical signal to obtain a first analog electrical signal;
  • the second coherent receiver is connected to the optical signal source, and configured to coherently mix the signal to be tested and the second optical signal to obtain a second analog electrical signal;
  • each of the coherent receivers includes at least one mixer and one photodetector. Two coherent receivers process two signals separately, one for each coherent receiver.
  • a signal processor 1204 the signal processor being coupled to the first coherent receiver and the second coherent receiver for converting the first analog electrical signal into a corresponding first time domain power signal, Converting the two analog electrical signals into a second time domain power signal, and determining a delay value between the first time domain power signal and the second time domain power signal; and the correspondence between the delay value and the dispersion Obtaining fiber dispersion during transmission of the signal to be tested.
  • the implementation of the optical signal source 1201 includes a plurality of, and the following two optimization implementations are provided:
  • the optical signal source includes two lasers, and the two lasers are respectively used to generate the first optical signal and the second optical signal. Specifically:
  • the optical signal source includes a laser source, an electro-optic modulator and a microwave signal source (the specific structure is shown in FIG. 13), specifically:
  • a laser source for generating an optical signal
  • the two input ends of the photoelectric modulator are respectively connected to the laser source and the output end of the microwave signal source, for performing carrier suppression modulation on the optical signal by using a signal generated by the microwave signal source to generate the first The optical signal and the second optical signal.
  • the optimization may be implemented by: a center frequency of the first optical signal is a center frequency of the signal to be tested plus a 1/2 baud rate; and a center frequency of the second optical signal is The center frequency of the signal to be tested is reduced by 1/2 baud rate.
  • the embodiment further provides another apparatus for monitoring chromatic dispersion of an optical communication network, the apparatus comprising:
  • the mixing module 1401 is configured to coherently mix the signal to be tested with the first optical signal to obtain a first analog electrical signal, and perform coherent mixing of the signal to be tested and the second optical signal to obtain a second analog electrical signal; a center frequency of the first optical signal and the second optical signal is on both sides of a center frequency of the signal to be tested, and a center frequency difference between the first optical signal and the second optical signal is equal to a baud rate ;
  • the conversion module 1402 is configured to convert the first analog electrical signal into a corresponding first time domain power signal, and convert the second analog electrical signal into a second time domain power signal;
  • the converting module 1402 is specifically configured to perform analog-to-digital conversion processing on the first analog electrical signal to obtain a first digital signal, and perform analog-to-digital conversion processing on the second analog electrical signal to obtain a second digital signal.
  • the value of each time of the first digital signal is modulo squared to obtain the first time domain power signal; and the value of each time of the second digital signal is modulo squared to obtain the second time domain power signal.
  • a delay value determining module 1403, configured to determine a delay value between the first time domain power signal and the second time domain power signal
  • the chromatic dispersion determining module 1404 is configured to obtain the fiber dispersion in the transmission of the signal to be tested by the correspondence between the delay value and the dispersion.
  • the chromatic dispersion determining module is specifically configured to use the delay value and the formula according to the delay value Determining a fiber dispersion in the transmission of the signal to be tested; wherein the ⁇ 0 is a delay value between the two time domain power signals, and the T is an equivalent baseband signal of the signal to be tested The symbol width, ⁇ is the center frequency of the signal to be tested, and c is the speed of light.
  • the dispersion detection method provided by the embodiment of the present invention obtains two analog electrical signals on the upper and lower sidebands of the optical signal to be measured by coherent mixing of the signal to be tested and a specific optical signal, and then passes the delay value between the two analog electrical signals. Determining the dispersion, so the solution provided in this embodiment is independent of the modulation pattern and is related to the baud rate, so the algorithm is simple and easy to implement;
  • the method provided by the embodiment of the present invention can accurately and effectively implement optical network CD monitoring, and provides a reliable information source for optical network management, thereby making optical network monitoring management and operation more convenient.

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Abstract

本发明公开了一种监测光通信网络色散的方法及装置，该方法包括：将待测信号与第一光信号进行相干混频得到第一模拟电信号；将所述待测信号与第二光信号进行相干混频得到第二模拟电信号；其中，所述第一光信号和所述第二光信号的中心频率在所述待测信号的中心频率两边，且所述第一光信号和所述第二光信号的中心频率差等于波特率；将所述第一模拟电信号转换为对应的第一时域功率信号，将所述第二模拟电信号转换为第二时域功率信号；确定所述第一时域功率信号和第二时域功率信号之间的时延值；通过所述时延值与色散之间的对应关系获得所述待测信号传输过程中的光纤色散。本发明公开的方法及装置解决脉冲时延法在远距离传输应用中难以实现的问题。

Description

一种监测光通信网络色散的方法及装置
本申请要求在2015年10月31日提交中国专利局、申请号为201510731949.3、发明名称为“一种监测光通信网络色散的方法及装置”的中国专利申请的优先权，其全部内容通过引用结合在本申请中。
技术领域
本发明涉及通信技术领域，尤其涉及一种监测光通信网络色散的方法及装置。
背景技术
随着人们对数据业务需求的不断增大，大容量高速光纤传输网络逐渐成为了信息传输的主要方向。而光纤通信新技术的不断革新，也促成了光纤传输距离在逐年倍增，光参量的好坏成为了衡量光纤通信***的重要指标。为了能更好实现对光网络进行管理和监测，有必要对网络中传输的重要参量进行监测，光性能监测(Optical Performance Monitoring，OPM)随光纤通信的发展得到人们更多的关注。在众多参数中，光色散(Chromatic Dispersion，CD)是可反应光网络运行状态好坏的重要参量。
在光纤通信***中，光色散是衡量光纤链路质量的重要指标，对于估算和测量***具有重要的意义。光色散，指的是光波中各个频率分量传输速率的差异。如图1所示，光信号在光纤中是由不同的频率成份携带的，这些不同的频率成份通过同一介质时有不同的传播速度，这种现象就称为色散。在时间上表现为光脉冲在通过光纤传播时，其波形在时间上发生了展宽并引起信号畸变造成失真，从而引起接收错误，限制了光纤的传输容量。色散与光纤长度成线性关系，即光纤越长，色散越大。在光纤通信***传输的中间节点对CD进行监测，可以判断光信号经过的光纤长度，或者，在已知光纤长度的情况下，可以判断出光纤的色散参数。这些监测结果可以为光网络的通信质量评估提供一个重要的判断依据。
现有技术中测量色散的方法可以是脉冲时延法，该方法的具体实现可以是(该方法的实现如图2所示)：
用一台脉冲信号发生器去调制一个激光器，从激光器输出的光信号通过分光镜分为两路。一路进入被测光纤(由于色散作用，这一路的光脉冲信号被展宽)。另一路，不经过被测光纤，直接进入光监测器和接收机。将两路接收到的信号送入双踪示波器。从显示出的脉冲波形上分别测得两束光脉冲的宽度。假设输入光纤和从光纤输出的光脉冲波形都近似成高斯，用时域法测量经光纤传输造成的脉冲展宽可以计算出光纤的色散。
脉冲时延法是通过测定不同波长的窄光脉冲经过光纤传输后的时延差，直接由定义式得出光纤色散系数的一种方法。这种方法是将已知形状的窄脉冲(通常宽度为几百ps)注入待测光纤，由于光纤的色散，光脉冲沿光纤传输后将会发生展宽，在光纤输出端记录下该展宽的光脉冲波形，由输出脉冲宽度与输入脉冲宽度的差值，就可以得出色散导致的脉冲展宽，从而根据展宽可以估计得出光纤加入的色散。
根据上述脉冲时延法的实现方式可知，通过该方法估计色散需要有原始脉冲的比对，在实际远距离传输应用中难以实现。
发明内容
本发明提供一种监测光通信网络色散的方法及装置，本发明所提供的方法及装置解决现有脉冲时延法在远距离传输应用中难以实现的问题。
第一方面，提供一种监测光通信网络色散的方法，该方法包括：
将待测信号与第一光信号进行相干混频得到第一模拟电信号；
将所述待测信号与第二光信号进行相干混频得到第二模拟电信号；其中，所述第一光信号和所述第二光信号的中心频率在所述待测信号的中心频率两边，且所述第一光信号和所述第二光信号的中心频率差等于波特率；
将所述第一模拟电信号转换为对应的第一时域功率信号，将所述第二模拟电信号转换为第二时域功率信号；
确定所述第一时域功率信号和第二时域功率信号之间的时延值；
通过所述时延值与色散之间的对应关系获得所述待测信号传输过程中的光纤色散。
结合第一方面，在第一种可能的实现方式中，通过所述时延值与色散之间的对应关系获得所述待测信号传输过程中的光纤色散包括：
根据所述时延值和公式
Figure PCTCN2016086577-appb-000001
确定所述待测信号传输过程中的光纤色散；其中，所述τ0为所述两个时域功率信号之间的时延值，所述T为所述待测信号的等效基带信号的码元宽度，λ为所述待测信号的中心频率，c为光速。
结合第一方面或第一方面的第一种可能的实现方式，在第二种可能的实现方式中，将所述第一模拟电信号转换为对应的第一时域功率信号，将所述第二模拟电信号转换为第二时域功率信号包括:
对所述第一模拟电信号进行模数转换处理得到第一数字信号；对所述第二模拟电信号进行模数转换处理得到第二数字信号；
对所述第一数字信号每个时刻的值取模平方获得所述第一时域功率信号；对所述第二数字信号每个时刻的值取模平方获得所述第二时域功率信号。
结合第一方面的第二种可能的实现方式，在第三种可能的实现方式中，如果光信号是包括X偏振信号和Y偏振信号的信号，其中，X偏振信号和Y偏振信号是正交的，该方法包括：
将所述X偏振信号和Y偏振信号分别作为所述待测信号与所述第一光信号和所述第二光信号进行相干混频，得到第一光信号对应的X偏振模拟电信号Ux、第一光信号对应的Y偏振模拟电信号Uy和第二光信号对应的X偏振模拟电信号Lx；第二光信号对应的Y偏振模拟电信号Ly；其中，Ux和Lx是X偏振态信号分别与所述第一光信号和第二光信号进行相干混频得到的信号；Uy和Ly是Y偏振态信号分别与所述第一光信号和第二光信号进行相干 混频得到的信号；
则所述第一模拟电信号包括所述Ux和Uy，所述第二模拟电信号包括所述Lx和Ly。
第二方面，提供一种监测光通信网络色散的装置，该装置包括：
光信号源，用于产生第一光信号和第二光信号；其中，所述第一光信号和所述第二光信号的中心频率在待测信号的中心频率两边，且所述第一光信号和所述第二光信号的中心频率差等于波特率；
第一相干接收机，所述第一相干接收机与所述光信号源相连，用于将待测信号与第一光信号进行相干混频得到第一模拟电信号；
第二相干接收机，所述第二相干接收机与所述光信号源相连，用于将所述待测信号与第二光信号进行相干混频得到第二模拟电信号；
信号处理器，所述信号处理器与所述第一相干接收机和第二相干接收机相连，用于将所述第一模拟电信号转换为对应的第一时域功率信号，将所述第二模拟电信号转换为第二时域功率信号，并确定所述第一时域功率信号和第二时域功率信号之间的时延值；通过所述时延值与色散之间的对应关系获得所述待测信号传输过程中的光纤色散。
结合第二方面，在第一种可能的实现方式中，所述光信号源包括：
第一激光器，用于产生所述第一光信号；
第二激光器，用于产生所述第二光信号。
结合第二方面，在第二种可能的实现方式中，所述光信号源包括：
一个激光源，用于产生光信号；
一个光电调制器和一个微波信号源，所述光电调制器的两个输入端分别连接所述激光源和所述微波信号源的输出端，用于利用所述微波信号源产生的信号对所述光信号进行载波抑制调制产生所述第一光信号和第二光信号。
第三方面，提供一种监测光通信网络色散的装置，该装置包括：
相干接收模块，用于将待测信号与第一光信号进行相干混频得到第一模拟电信号；将所述待测信号与第二光信号进行相干混频得到第二模拟电信号； 其中，所述第一光信号和所述第二光信号的中心频率在所述待测信号的中心频率两边，且所述第一光信号和所述第二光信号的中心频率差等于波特率；
转换模块，用于将所述第一模拟电信号转换为对应的第一时域功率信号，将所述第二模拟电信号转换为第二时域功率信号；
时延值确定模块，用于确定所述第一时域功率信号和第二时域功率信号之间的时延值；
色散确定模块，用于通过所述时延值与色散之间的对应关系获得所述待测信号传输过程中的光纤色散。
结合第三方面，在第一种可能的实现方式中，色散确定模块具体用于根据所述时延值和公式
Figure PCTCN2016086577-appb-000002
确定所述待测信号传输过程中的光纤色散；其中，所述τ0为所述两个时域功率信号之间的时延值，所述T为所述待测信号的等效基带信号的码元宽度，λ为所述待测信号的中心频率，c为光速。
结合第三方面或第三方面的第一种可能的实现方式，在第二种可能的实现方式中，所述转换确定模块具体用于对所述第一模拟电信号进行模数转换处理得到第一数字信号；对所述第二模拟电信号进行模数转换处理得到第二数字信号；对所述第一数字信号每个时刻的值取模平方获得所述第一时域功率信号；对所述第二数字信号每个时刻的值取模平方获得所述第二时域功率信号。
上述技术方案中的一个或两个，至少具有如下技术效果：
本发明实施例提供的色散检测方法及装置通过待测信号与特定的光信号进行相干混频得到待测光信号上下边带的两个模拟电信号，再通过两个模拟电信号之间的时延值确定色散，所以本实施例提供的方案与调制码型无关，与波特率相关，所以算法简单，便于实现。
附图说明
图1为现有技术中光信号在光纤中传输的示意图；
图2为现有技术中测量色散的脉冲时延法的流程示意图；
图3a和图3b为现有技术中发射信号m1(t)的示意图；
图4a和图4b为现有技术中信号m2(t)的示意图；
图5为现有技术中信号m3(t)的示意图；
图6为m1(f)和m2(f)加载到光波上的示意图；
图7为出现时间延迟的两个信号做互相关的函数图象；
图8为本发明实施例提供的一种监测光通信网络色散的方法的信号处理示意图；
图9为本发明实施例提供的一种监测光通信网络色散的方法流程示意图；
图10为本发明实施例中通过将两个时域功率信号进行互相关确定两个信号之间的时延值的信号处理示意图；
图11为本发明实施例将待检测光信号两个偏振态的信号当做两个独立的信号进行处理的信号处理示意图；
图12为本发明实施例提供的一种监测光通信网络色散的装置结构示意图；
图13为本发明实施例提供的一种光信号源的结构示意图；
图14为本发明实施例提供的另外一种监测光通信网络色散的装置结构示意图。
具体实施方式
为使本发明实施例的目的、技术方案和优点更加清楚，下面将结合本发明实施例中的附图，对本发明实施例中的技术方案进行清楚、完整地描述，显然，所描述的实施例是本发明一部分实施例，而不是全部的实施例。基于本发明中的实施例，本领域普通技术人员在没有作出创造性劳动前提下所获得的所有其他实施例，都属于本发明保护的范围。
为了方便理解本发明实施例所提供的方法，以下结合附图对本发明实施例所提供方法的实现原理进行说明，具体包括：
从发射机发射出来的光信号的时域形式可表示为：
从发射机发射出来的光信号的时域形式可表示为：
ES(t)＝{[∑nsnδ(t-nT)]*p(t)}c(t)(其中，sn为信号比特数据，δ(t)为脉冲函数，p(t)为脉冲波形，c(t)为光载波,*代表卷积运算)，T是信号的符号周期。令：
m1(t)＝∑nsnδ(t-nT)
m2(t)＝p(t)
m3(t)＝c(t)；
其中，m1(t)为发射信号的基带形式，表现为周期为T的脉冲函数(如图3a所示)，其频域形式如图3b所示，m1(f)是周期为1/T的周期信号。
p(t)为脉冲波形，若p(t)取非归零矩形波，则m2(t)如图4a所示的：m2(t)对应的频域形式m2(f)为图4b所示，m2(t)为主瓣带宽1/T的带限信号；
m3(t)为光载波，由于光载波为频率为f1的单载波，在频域上可表达为一个脉冲信号(如图5所示)；
因为信号在传输过程中是将发射信号叠加在光载波信号上发送的，所以：
发射的时域光信号：ES(t)＝[m1(t)*m2(t)]·m3(t)
在频域上可表达为：ES(f)＝[m1(f)·m2(f)]*m3(f)
m1(f)为周期为1/T的周期信号，m2(f)为主瓣带宽1/T的对称的带限信号，两者相乘，再加载到光波中心频率f1上(如图6所示)，则在有限带宽内(f1-1/T到f1+1/T)，根据图6可知只有f1-1/2T和f1+1/2T处可以得到完全相同的周期重复的信号。
由于在f1-1/2T和f1+1/2T处的两个窄带信号，相距1/T，满足m1(f)的最小周期1/T，并且在m2(f)脉冲波形的带宽内关于中心波长轴对称，所以如果没有加入色散，在两个相干接收机分别得到的f1-1/2T和f1+1/2T处的两个窄带 信号应该是完全相同的。所以通过比较f1-1/2T和f1+1/2T处的两个窄带信号的差异可以检测出信号传输过程中的色散。
色散测量的原理在于加入色散后，接收得到的本应完全相同的f1-1/2T和f1+1/2T处的两个窄带信号，在色散影响下产生了时延，在时域上两个信号会出现错位。
对出现时间延迟的两个信号做互相关，其函数图象如图7所示，该函数的图像存在一个尖峰。尖峰的位置或横坐标表示两个信号错开的采样点的数目。将采集到的上下边带1/2(即f1-1/2T和f1+1/2T)时域功率信号，即两个时域数据做互相关，可以得到一个相关函数，而相关函数的尖峰的横坐标指代的是两个应该相同时域数据(上下边带1/2时域功率信号)在加入色散后所产生的延迟，而这个时间延迟与加入的色散值成正比。通过上述原理可以计算出信号传输过程中的色散。
实施例
基于上述实现原理本发明实施例提供一种监测光通信网络色散的方法(方法流程如图9所示，具体的信号流处理示意如图8所示)，该方法具体包括：
步骤901，将待测信号与第一光信号进行相干混频得到第一模拟电信号；将所述待测信号与第二光信号进行相干混频得到第二模拟电信号；其中，所述第一光信号和所述第二光信号的中心频率在所述待测信号的中心频率两边，且所述第一光信号和所述第二光信号的中心频率差等于波特率；
在该实施例中，第一光信号和第二光信号在待测信号中心频率加减1/2波特率处的附近则可以实现光纤色散的测量。第一光信号和第二光信号的最优实施例是：第一光信号的中心频率为所述待测信号的中心频率加1/2波特率，第二光信号的中心频率为所述待测信号的中心频率减1/2波特率。
步骤902，将所述第一模拟电信号转换为对应的第一时域功率信号，将所述第二模拟电信号转换为第二时域功率信号；
在该实施例中，进行转化的具体实现可以是：
对所述第一模拟电信号进行模数转换处理得到第一数字信号；对所述第二模拟电信号进行模数转换处理得到第二数字信号；
对所述第一数字信号每个时刻的值取模平方获得所述第一时域功率信号；对所述第二数字信号每个时刻的值取模平方获得所述第二时域功率信号。
步骤903，确定所述第一时域功率信号和第二时域功率信号之间的时延值；
在该实施例中，模拟电信号转换为时域功率信号后可以通过各种方式确定两个时域功率信号之间的时延，在该实施例中最优化的方式是通过将两个时域功率信号进行互相关确定两个信号之间的时延值(具体实现原理如图10所示)。
采用两个时域功率信号互相关确定时延值的方式时，两个时间功率信号的相关函数含有一个尖峰，尖峰的位置τ0表征的是中心频率加减1/2波特率处的两个功率信号的时延值(如图7所示)，该时延值与色散大小成正比。时延值指的是，中心频率加减1/2波特率处的两个模拟电信号在没有加入色散时应该为周期重复相同的信号，在加入色散后由于两个信号的载频不同受到色散影响，从而两个信号出现错位产生时延。加入的色散正比于延时量，所以根据时延值可以计算色散。
步骤904，通过所述时延值与色散之间的对应关系获得所述待测信号传输过程中的光纤色散。
以下结合附图8，对本发明实施例所提供方法中，信号的处理流程做进一步的详细说明，具体实现可以是：
将待测信号输入两个相干接收机，两个相干接收机分别将待测信号与本激光1和本振激光2相干混频得到两个模拟电信号，其中两个相干接收机对信号的处理流程完全相同，以下以本振激光1对应的相干接收机的信号处理流程为例进行说明：
待测信号与本振激光1同时输入相干接收机，相干接收机会将待测信号与本振激光1进行混频，然后得到四路光信号；然后将四路光信号进行分成两组光信号，对每组光信号进行光电探测然后得到一路模拟电信号，两组光信号对应得到两路模拟电信号(每一路模拟电信号代表了最终输出的模拟电信号的一部分的信息)，两路模拟电信号组合形成相干接收机最后输出的模拟电信号(即该实施例中的第一模拟电信号)；
再经过模数转换模块，将模拟电信号转换成离散的数字电信号a(其中，该数字信号a是对应待测信号f-1/2T频率处的信号)。
基于本振激光1和待测信号的相同处理流程，本振激光2和待测信号经过相同的处理过程也可以获得一个数字电信号b(其中，该数字信号b是对应待测信号f+1/2T频率处的信号)。
信号处理器(例如DSP)将数字电信号a每个时刻的值取模平方获得第一时域功率信号；将数字电信号b每个时刻的值取模平方获得第二时域功率信号(其中，时域功率信号代表数字电信号在每个时刻的功率)；
然后第一时域功率信号和第二时域功率信号进行互相关操作之后，得到两个时域功率信号之间的时延值，从而根据色散与时延值之间的关系可以确定光纤传输的时延值。
具体的，可以通过以下公式确定光纤色散：
Figure PCTCN2016086577-appb-000003
其中，所述τ0为所述两个时域功率信号之间的时延值，所述T为所述待测信号的等效基带信号的码元宽度，λ为所述待测信号的中心频率，c为光速。
另外，因为现在的光通信***通常使用偏振复用技术，偏振复用技术是将信息调制到两个正交的偏振状态上(即X偏振和Y偏振)。为了能够监测偏振复用***的色散，可以使用偏振分束器(Polarization Beam Splitter，PBS)将待测信号和本振激光分成正交的两个偏振态分别进行色散估计。所以在本 实施例所提供的方案中，当待检测的光信号包括X偏振信号和Y偏振信号，其中X偏振信号和Y偏振信号是正交的，可以将X偏振信号和Y偏振信号分别作为独立的信号与第一光信号和第二光信号进行混频操作得到四个模拟电信号，为了确定时延值，则需要将四个模拟电信号组合形成2个模拟电信号，则具体实现可以是：
四个模拟电信号为：Ux、Lx、Uy和Ly，具体是
X偏振态信号分别与所述第一光信号和第二光信号进行相干接收得到X偏振方向上的信号，该信号包括第一光信号对应的X偏振模拟电信号Ux、第二光信号对应的X偏振模拟电信号Lx；
Y偏振态信号分别与所述第一光信号和第二光信号进行相干混频得到Y偏振方向上的信号，该信号包括第一光信号对应的Y偏振模拟电信号Uy和第二光信号对应的Y偏振模拟电信号Ly。
对应的第一模拟电信号和第二模拟电信号分别都包括两个部分，具体为：
则所述第一模拟电信号包括所述Ux和Uy，所述第二模拟电信号包括所述Lx和Ly。
进一步，确定时域功率信号则可以是：将Ux和Uy分别取模平方(即|Ux|^2+|Uy|^2)得到第一时域功率信号，将所述Lx和Ly分别取模平方(即|Lx|^2+|Ly|^2)得到第二时域功率信号。
在该实施例中，因为通过对这两个偏振态的功率信号做互相关求时延值，可以排除偏振模色散的影响。因为如果色散***中同时也存在偏振模色散，偏振模色散参量是不会影响|Ux|^2+|Uy|^2和|Lx|^2+|Ly|^2的量值，所以采用|Ux|^2+|Uy|^2和|Lx|^2+|Ly|^2做功率互相关可以得到比较准确的时延值。
另外，在该实例中，可以将待检测光信号对应的两个偏振态的信号当做两个独立的信号，然后分别与第一光信号和第二光信号进行相干接收等处理从而得到两个光纤色散值(信号流处理如图11所示)。
本发明实施例提供的方法与调制码型无关，与波特率有关，所以算法简单，便于实现；
另外，本发明实施例所提供的方法能精确有效实现光网络CD监测，为光网络的管理提供一个可靠信息来源，使光网络监控管理和运行更便捷。
另一实施例
如图12所示，该实例提供一种监测光通信网络色散的装置，该装置包括：
光信号源1201，用于产生第一光信号和第二光信号；其中，所述第一光信号和所述第二光信号的中心频率在待测信号的中心频率两边，且所述第一光信号和所述第二光信号的中心频率差等于波特率；
第一相干接收机1202，该第一相干接收机与所述光信号源相连，用于将待测信号与第一光信号进行相干混频得到第一模拟电信号；
第二相干接收机1203，该第二相干接收机与所述光信号源相连，用于将所述待测信号与第二光信号进行相干混频得到第二模拟电信号；
在具体的实现环境中，每个相干接收机中至少包括一个混频器、一个光电探测器。两个相干接收机是分别对两个信号进行处理，每个相干接收机对应一个信号。
信号处理器1204，该信号处理器与所述第一相干接收机和第二相干接收机相连，用于将所述第一模拟电信号转换为对应的第一时域功率信号，将所述第二模拟电信号转换为第二时域功率信号，并确定所述第一时域功率信号和第二时域功率信号之间的时延值；通过所述时延值与色散之间的对应关系获得所述待测信号传输过程中的光纤色散。
在具体的使用环境中，光信号源1201的实现方式包括多种，以下提供两种最优化的实现方式：
方式一
该光信号源中包括两个激光器，两个激光器分别用于产生第一光信号和第二光信号。具体为：
第一激光器，用于产生所述第一光信号；
第二激光器，用于产生所述第二光信号。
方式二
该光信号源中包括一个激光源、一个光电调制器和一个微波信号源(具体结构如图13所示)，具体的：
激光源，用于产生光信号；
该光电调制器的两个输入端分别连接所述激光源和所述微波信号源的输出端，用于利用所述微波信号源产生的信号对所述光信号进行载波抑制调制产生所述第一光信号和第二光信号。
在该实施例中，最优化的实现方式可以是：所述第一光信号的中心频率为所述待测信号的中心频率加1/2波特率；所述第二光信号的中心频率为所述待测信号的中心频率减1/2波特率。
另一实施例
如图14所示，本实施例还提供另外一种监测光通信网络色散的装置，该装置包括：
混频模块1401，用于将待测信号与第一光信号进行相干混频得到第一模拟电信号；将所述待测信号与第二光信号进行相干混频得到第二模拟电信号；其中，所述第一光信号和所述第二光信号的中心频率在所述待测信号的中心频率两边，且所述第一光信号和所述第二光信号的中心频率差等于波特率；
转换模块1402，用于将所述第一模拟电信号转换为对应的第一时域功率信号，将所述第二模拟电信号转换为第二时域功率信号；
可选的，该转换模块1402具体用于对所述第一模拟电信号进行模数转换处理得到第一数字信号；对所述第二模拟电信号进行模数转换处理得到第二数字信号；对所述第一数字信号每个时刻的值取模平方获得所述第一时域功率信号；对所述第二数字信号每个时刻的值取模平方获得所述第二时域功率信号。
时延值确定模块1403，用于确定所述第一时域功率信号和第二时域功率信号之间的时延值；
色散确定模块1404，用于通过所述时延值与色散之间的对应关系获得所述待测信号传输过程中的光纤色散。
可选的，该色散确定模块具体用于根据所述时延值和公式
Figure PCTCN2016086577-appb-000004
确定所述待测信号传输过程中的光纤色散；其中，所述τ0为所述两个时域功率信号之间的时延值，所述T为所述待测信号的等效基带信号的码元宽度，λ为所述待测信号的中心频率，c为光速。
本申请实施例中的上述一个或多个技术方案，至少具有如下的技术效果：
本发明实施例提供的色散检测方法通过待测信号与特定的光信号进行相干混频得到待测光信号上下边带的两个模拟电信号，再通过两个模拟电信号之间的时延值确定色散，所以本实施例提供的方案与调制码型无关，与波特率相关，所以算法简单，便于实现；
另外，本发明实施例所提供的方法能精确有效实现光网络CD监测，为光网络的管理提供一个可靠信息来源，使光网络监控管理和运行更便捷。
本发明所述的方法并不限于具体实施方式中所述的实施例，本领域技术人员根据本发明的技术方案得出其它的实施方式，同样属于本发明的技术创新范围。
显然，本领域的技术人员可以对本发明进行各种改动和变型而不脱离本发明的精神和范围。这样，倘若本发明的这些修改和变型属于本发明权利要求及其等同技术的范围之内，则本发明也意图包含这些改动和变型在内。

Claims (10)

  1. 一种监测光通信网络色散的方法，其特征在于，该方法包括：
    将待测信号与第一光信号进行相干混频得到第一模拟电信号；
    将所述待测信号与第二光信号进行相干混频得到第二模拟电信号；其中，所述第一光信号和所述第二光信号的中心频率在所述待测信号的中心频率两边，且所述第一光信号和所述第二光信号的中心频率差等于波特率；
    将所述第一模拟电信号转换为对应的第一时域功率信号，将所述第二模拟电信号转换为第二时域功率信号；
    确定所述第一时域功率信号和第二时域功率信号之间的时延值；
    通过所述时延值与色散之间的对应关系获得所述待测信号传输过程中的光纤色散。
  2. 如权利要求1所述的方法，其特征在于，通过所述时延值与色散之间的对应关系获得所述待测信号传输过程中的光纤色散包括：
    根据所述时延值和公式
    Figure PCTCN2016086577-appb-100001
    确定所述待测信号传输过程中的光纤色散；其中，所述τ0为所述两个时域功率信号之间的时延值，所述T为所述待测信号的等效基带信号的码元宽度，λ为所述待测信号的中心频率，c为光速。
  3. 如权利要求1或2所述的方法，其特征在于，将所述第一模拟电信号转换为对应的第一时域功率信号，将所述第二模拟电信号转换为第二时域功率信号包括:
    对所述第一模拟电信号进行模数转换处理得到第一数字信号；对所述第二模拟电信号进行模数转换处理得到第二数字信号；
    对所述第一数字信号每个时刻的值取模平方获得所述第一时域功率信号；对所述第二数字信号每个时刻的值取模平方获得所述第二时域功率信号。
  4. 如权利要求3所述的方法，其特征在于，如果光信号是包括X偏振信 号和Y偏振信号的信号，其中，X偏振信号和Y偏振信号是正交的，该方法包括：
    将所述X偏振信号和Y偏振信号分别作为所述待测信号与所述第一光信号和所述第二光信号进行相干混频，得到第一光信号对应的X偏振模拟电信号Ux、第一光信号对应的Y偏振模拟电信号Uy和第二光信号对应的X偏振模拟电信号Lx；第二光信号对应的Y偏振模拟电信号Ly；其中，Ux和Lx是X偏振态信号分别与所述第一光信号和第二光信号进行相干混频得到的信号；Uy和Ly是Y偏振态信号分别与所述第一光信号和第二光信号进行相干混频得到的信号；
    则所述第一模拟电信号包括所述Ux和Uy，所述第二模拟电信号包括所述Lx和Ly。
  5. 一种监测光通信网络色散的装置，其特征在于，该装置包括：
    光信号源，用于产生第一光信号和第二光信号；其中，所述第一光信号和所述第二光信号的中心频率在待测信号的中心频率两边，且所述第一光信号和所述第二光信号的中心频率差等于波特率；
    第一相干接收机，所述第一相干接收机与所述光信号源相连，用于将待测信号与第一光信号进行相干混频得到第一模拟电信号；
    第二相干接收机，所述第二相干接收机与所述光信号源相连，用于将所述待测信号与第二光信号进行相干混频得到第二模拟电信号；
    信号处理器，所述信号处理器与所述第一相干接收机和第二相干接收机相连，用于将所述第一模拟电信号转换为对应的第一时域功率信号，将所述第二模拟电信号转换为第二时域功率信号，并确定所述第一时域功率信号和第二时域功率信号之间的时延值；通过所述时延值与色散之间的对应关系获得所述待测信号传输过程中的光纤色散。
  6. 如权利要求5所述的装置，其特征在于，所述光信号源包括：
    第一激光器，用于产生所述第一光信号；
    第二激光器，用于产生所述第二光信号。
  7. 如权利要求5所述的装置，其特征在于，所述光信号源包括：
    一个激光源，用于产生光信号；
    一个光电调制器和一个微波信号源，所述光电调制器的两个输入端分别连接所述激光源和所述微波信号源的输出端，用于利用所述微波信号源产生的信号对所述光信号进行载波抑制调制产生所述第一光信号和第二光信号。
  8. 一种监测光通信网络色散的装置，其特征在于，该装置包括：
    相干接收模块，用于将待测信号与第一光信号进行相干混频得到第一模拟电信号；将所述待测信号与第二光信号进行相干混频得到第二模拟电信号；其中，所述第一光信号和所述第二光信号的中心频率在所述待测信号的中心频率两边，且所述第一光信号和所述第二光信号的中心频率差等于波特率；
    转换模块，用于将所述第一模拟电信号转换为对应的第一时域功率信号，将所述第二模拟电信号转换为第二时域功率信号；
    时延值确定模块，用于确定所述第一时域功率信号和第二时域功率信号之间的时延值；
    色散确定模块，用于通过所述时延值与色散之间的对应关系获得所述待测信号传输过程中的光纤色散。
  9. 如权利要求8所述的装置，其特征在于，色散确定模块具体用于根据所述时延值和公式
    Figure PCTCN2016086577-appb-100002
    确定所述待测信号传输过程中的光纤色散；其中，所述τ0为所述两个时域功率信号之间的时延值，所述T为所述待测信号的等效基带信号的码元宽度，λ为所述待测信号的中心频率，c为光速。
  10. 如权利要求8或9所述的装置，其特征在于，所述转换确定模块具体用于对所述第一模拟电信号进行模数转换处理得到第一数字信号；对所述第二模拟电信号进行模数转换处理得到第二数字信号；对所述第一数字信号每个时刻的值取模平方获得所述第一时域功率信号；对所述第二数字信号每个时刻的值取模平方获得所述第二时域功率信号。
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