WO2012133473A1 - Système de communication optique à pré-compensation de dispersion en longueur d'onde - Google Patents

Système de communication optique à pré-compensation de dispersion en longueur d'onde Download PDF

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Publication number
WO2012133473A1
WO2012133473A1 PCT/JP2012/058043 JP2012058043W WO2012133473A1 WO 2012133473 A1 WO2012133473 A1 WO 2012133473A1 JP 2012058043 W JP2012058043 W JP 2012058043W WO 2012133473 A1 WO2012133473 A1 WO 2012133473A1
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Prior art keywords
chromatic dispersion
transmission
optical communication
delay amount
signal
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PCT/JP2012/058043
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English (en)
Japanese (ja)
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弘法 村木
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日本電気株式会社
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Publication of WO2012133473A1 publication Critical patent/WO2012133473A1/fr

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
    • H04B10/25—Arrangements specific to fibre transmission
    • H04B10/2507—Arrangements specific to fibre transmission for the reduction or elimination of distortion or dispersion
    • H04B10/2513—Arrangements specific to fibre transmission for the reduction or elimination of distortion or dispersion due to chromatic dispersion
    • H04B10/25133—Arrangements specific to fibre transmission for the reduction or elimination of distortion or dispersion due to chromatic dispersion including a lumped electrical or optical dispersion compensator
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B2210/00—Indexing scheme relating to optical transmission systems
    • H04B2210/25—Distortion or dispersion compensation
    • H04B2210/254—Distortion or dispersion compensation before the transmission line, i.e. pre-compensation

Definitions

  • the present invention relates to an optical communication system that compensates for chromatic dispersion in advance.
  • the spectrum width of a signal widens, and the chromatic dispersion received varies depending on the wavelength difference. Specifically, the propagation speed on the long wavelength side is slow and the propagation speed on the short wavelength side is high, centering on the zero dispersion wavelength. As a result, the transmitted signal is greatly distorted in the fiber transmission path, leading to waveform deterioration. This is due to the material dispersion and structural dispersion of the optical fiber. For example, it is affected by various factors such as fiber characteristics, environmental temperature, and transmission distance. It is a big factor that restricts. Various techniques have been proposed to avoid waveform degradation due to chromatic dispersion.
  • a method using a dispersion shifted fiber (DSF) or a dispersion compensation fiber (DCF) has been proposed.
  • the DSF is obtained by shifting the zero dispersion wavelength to the 1.55 ⁇ m band, and is suitable for optical communication using a 1.55 ⁇ m band optical signal by using the DSF for the transmission line.
  • the DCF is a dispersion compensating fiber having reverse characteristics to the optical fiber transmission line.
  • the chromatic dispersion of the DSF is opposite in sign to the chromatic dispersion of the transmission line. Therefore, chromatic dispersion compensation can be realized by connecting a DCF having an appropriate length that cancels out the chromatic dispersion amount of the transmission line in series in the transmission line.
  • the related technology not only requires a number of DCFs to appropriately compensate for the amount of chromatic dispersion, but also requires a huge amount of system construction and management, and lacks system expandability and flexibility.
  • the DCF is not only high in cost, but also increases in size when it is a module, and is greatly affected by insertion loss and environmental temperature when it is connected in multiple stages. For this reason, when performing optical transmission, it has been difficult to obtain sufficient chromatic dispersion compensation performance with the above-described related technology, and there has been a problem that flexible network design rich in expandability cannot be performed.
  • Various methods have been proposed to solve this problem.
  • Patent Document 1 estimates the chromatic dispersion effect caused by an optical fiber depending on the distance propagated by the optical fiber and the type of optical fiber, and corrects the transmission signal to reduce the interference power caused by chromatic dispersion and frequency-dependent circuit characteristics. The technology to the effect is described. Patent Document 2 describes the following technique.
  • Patent Document 3 in an optical transmission system in which chromatic dispersion compensation is performed using a chromatic dispersion compensation device, the wavelength of the transmitter 10 is varied based on wavelength control information to optimize the chromatic dispersion compensation amount for each channel. The technology to the effect is described.
  • Patent Document 4 describes a technique for obtaining an optical fiber communication system capable of compensating for chromatic dispersion in an optical fiber transmission line at high speed and with high precision.
  • Patent Document 5 also describes an optical fiber communication technique capable of compensating for chromatic dispersion in an optical fiber transmission line at high speed and with high precision. This is a more specific configuration by adding an OSC (monitoring optical interface) for chromatic dispersion control to the technique of the above-mentioned Patent Document 4.
  • OSC monitoring optical interface
  • Patent Document 6 discloses a technology that can be easily mounted on an optical communication terminal or a regenerative repeater in an ultra-high-speed optical transmission system, and can precisely adjust the chromatic dispersion of an optical fiber transmission line by a simple and versatile control method. Are listed. In this document, when optimal equalization control of chromatic dispersion at the receiving side is performed, switching between coarse and wide range search or fine and narrow range adjustment is performed according to the alarm state. The technology is described.
  • Patent Document 1 has a problem that it is necessary to grasp the transmission line characteristics of the optical fiber transmission line in advance.
  • Patent Document 2 has a problem that it is necessary to prepare a reference waveform that has not undergone waveform deterioration.
  • Patent Document 3 it is necessary to prepare an expensive chromatic dispersion compensation device.
  • the technologies of Patent Documents 4 and 5 require a large-capacity lookup table, a digital FIR filter with a long tap number, and a high-speed analog transversal filter as a precoder for chromatic dispersion equalization. There is a problem of growing.
  • Patent Document 6 equalizes chromatic dispersion on the reception side, and is not a technique for performing equalization in advance on the transmission side.
  • An object of the present invention is to provide a chromatic dispersion precompensated optical communication system capable of accurately and automatically compensating for chromatic dispersion in an optical fiber transmission line.
  • the chromatic dispersion pre-compensation optical communication transmitting / receiving apparatus includes: a decomposing unit that decomposes a signal to be transmitted for each frequency component; a calculating unit that calculates a delay amount to be added to each of the frequency components; Delay means for delaying each frequency component; and synthesis transmission means for synthesizing the delayed signals and sending the synthesized signals to a transmission line.
  • the chromatic dispersion pre-compensation optical communication transmission / reception method of the present invention decomposes a signal to be transmitted for each frequency component, calculates a delay amount to be added to each frequency component, and delays each frequency component based on the delay amount. Are combined, and the combined signal is sent to the transmission line.
  • the present invention has the following effects.
  • the present invention can provide a chromatic dispersion precompensation optical communication system capable of accurately and automatically compensating for chromatic dispersion in an optical fiber transmission line.
  • FIG. 1 shows the configuration of the chromatic dispersion precompensation optical communication system of the first embodiment.
  • Each of the transmission side node 101a and the reception side node 101b is an optical communication node, has a function and a port for transferring frames to each other, and is connected via communication paths 101c and 101d.
  • other devices for transmitting and receiving signals are connected to the nodes 101a and 101b via ports 102a and 102b.
  • the transmitting side node 101a transmits a signal to be transmitted to the receiving side node 101b (and its subordinates) among the signals received from other devices connected to the apparatus to the communication path 101c.
  • the receiving side node 101b receives the signal transmitted from the transmitting side node 101a via the communication path 101c, and transmits it to the corresponding other device connected to the apparatus.
  • the transmitting side node 101a has a port 102a for receiving a signal input from another connected device.
  • the transmission side node 101a has a Maper 103a that adds an error correction code (for example, FEC: Forward Error Correction) to the received signal and performs mapping processing on an OTN (Optical Transport Network) or the like.
  • OTN is a high-speed signal frame standardized by ITU-T (International Telecommunication Union Telecommunication Standardization Sector).
  • the transmission-side node 101a includes a Fourier transform circuit 105a that converts a time-domain signal into a frequency-domain signal, and a coefficient multiplier circuit 106a that multiplies the frequency-domain signal by a coefficient that performs chromatic dispersion compensation. Further, the transmission-side node 101a includes an inverse Fourier transform circuit 107a that converts a frequency domain signal into a time domain signal. In addition, the transmission side node 101a performs mapping processing to an OTN (Optical Transport Network) suitable for optical fiber communication and the like, and also performs E / O (Electrical / An optical converter circuit 108a.
  • OTN Optical Transport Network
  • the transmission side node 101a has a monitoring information reception INF (Interface) 109a that is an interface for receiving the number of bit errors (number of bit errors per unit time) transmitted from the reception side node. Further, the transmission side node 101a includes an optimization circuit 1010a that detects an optimum value based on the notified error information, and a coefficient calculation circuit 1011a that calculates a chromatic dispersion compensation coefficient based on the optimum value.
  • the reception-side node 101b includes an O / E circuit 105b that performs processing for converting an optical signal received from the optical fiber transmission path into an electrical signal and demodulation processing for the received signal.
  • the receiving node 101b performs demapping and error correction processing on the received data (for example, OTN), and converts it into a signal (for example, Ethernet (registered trademark)) suitable for communication with a device connected to the port 102b. , And a Demapper 103b that transmits a signal to the port 102b.
  • the receiving side node 101b is a monitoring circuit 107b that monitors bit error information of the port 102b and the Demapper 103b connected to other devices, and a monitoring that is an interface for transmitting the obtained bit error information to the transmitting side node 101a.
  • An information transmission INF 106b is included.
  • FIG. 1 is a block diagram showing the configuration of a system according to the first embodiment.
  • a chromatic dispersion pre-compensation optical communication system in the case of transmitting an optical signal from the transmission side node 101a to the reception side node 101b will be described.
  • the Maper 103a When a transmission signal is input from the port 102a, the signal is input to the Maper 103a. At this time, the input signal may be an optical signal or an electric signal.
  • an optical signal is converted into an electric signal, and an electric signal is directly transmitted to Mapper.
  • Mapper 103a an error correction code (for example, FEC) is added to the input client signal. It is mapped to OTN or the like, which is an optical signal frame standardized in 709, and then transmitted to the Fourier transform circuit 105a.
  • the Fourier transform circuit 105a converts the input signal from a time domain signal to a frequency domain signal.
  • the frequency domain signal includes both data on amplitude components and data on phase components in the frequency domain.
  • the monitoring information reception INF 109a it is assumed that the information on the number of bit errors fed back from the receiving side node 101b is received by the monitoring information reception INF 109a.
  • the communication path 101d may be directly connected to the receiving side node 101b, or may constitute a management network as shown in FIG.
  • control is performed by the optimization circuit 1010a so that an optimum coefficient for compensating chromatic dispersion is calculated and set by the coefficient arithmetic circuit 1011a.
  • the theory of a transfer function representing the chromatic dispersion of an optical fiber transmission line and the theory of calculating a coefficient having an inverse characteristic from the transfer function are generally widely known. However, it is not easy to measure the chromatic dispersion of an actual optical fiber transmission line accurately and in real time to obtain the true value of chromatic dispersion.
  • optimal chromatic dispersion compensation is sequentially performed based on transmission quality information such as an error rate and the number of error corrections in error correction processing included in the monitoring information fed back from the opposite optical communication apparatus.
  • the coefficient is obtained by the optimization circuit 1010a. A control method for obtaining the optimum value will be described later.
  • the coefficient multiplication circuit 106a multiplies the frequency domain signal transmitted from the Fourier transform circuit 105a by the chromatic dispersion correction coefficient set by the coefficient calculation circuit 1011a, thereby arriving at the receiving side node by the optical frequency. Compensate for the time difference. This process is called pre-equalization.
  • Pre-equalization corresponds to giving the inverse characteristic of the waveform degradation received by the communication channel 101c, and is for adaptively equalizing the waveform degradation received by the communication channel 101c.
  • the pre-equalized signal is transmitted to the inverse Fourier transform circuit 107a and converted from a frequency domain signal to a time domain signal.
  • the overlap-save method, the overlap-add method, or the like may be used for a series of processes including the conversion to the frequency domain by the Fourier transform circuit 105a, the process by the coefficient multiplication circuit 106a, and the process by the inverse Fourier transform circuit 107a. .
  • a method using the overlap-add method will be described later.
  • the signal converted into the time domain is sent to an E / O circuit (modulation circuit) 108a.
  • the E / O circuit (modulation circuit) 108a performs modulation processing on the signal by the set method and transmits the signal to the communication path 101c.
  • Examples of the modulation process include BPSK (Binary Phase Shift Keying), QPSK (Quadrature Phase Shift Keying), and QAM (Quadrature Amplitude Modulation).
  • the modulation process such as QPSK includes an encoding process for converting an electric signal into a signal to be carried on an optical signal and a modulation process (for example, an LN modulator) for modulating light from a laser.
  • FIG. 3 shows an outline of a series of processes such as Fourier transform, coefficient multiplication, and inverse Fourier transform when the overlap-add method is used.
  • the rectangle which is inclined obliquely shown in the lower part of FIG. 3 indicates that processing for compensating for different arrival times depending on frequency components due to chromatic dispersion has been performed. Assuming that the sign of the chromatic dispersion coefficient is positive, it is predicted that the high frequency component will arrive first, and signal processing is performed so that the transmission timing of the high frequency component is delayed.
  • the Fourier transform circuit 105a determines a section for Fourier transform so that the Fourier transform sections 301a, 301b, and 301c overlap each other.
  • the signals in the Fourier transform sections 301a and 301b are subjected to Fourier transform processing from the time domain signal to the frequency domain signal by the Fourier transform circuit 105a.
  • the converted frequency domain signals 304a and 304b are multiplied by a coefficient for correcting chromatic dispersion in the coefficient multiplication circuit 106a.
  • a coefficient for correcting chromatic dispersion is set by the coefficient calculation circuit 1011a.
  • the frequency domain signals 304a and 304b are subjected to inverse Fourier transform processing by the inverse Fourier transform circuit 107a.
  • the obtained signals 308a and 308b after inverse Fourier transform are subjected to removal processing at both ends of the signal, and a pre-equalized transmission signal is obtained based on these signals.
  • the receiving side node 101b in FIG. 1 receives a signal from the communication path 101c.
  • the O / E circuit 105b converts the received optical signal into an electrical signal, and performs a demodulation process on the modulation performed by the E / O circuit 108a.
  • the Demapper 103b performs demapping processing and error correction processing on the signal transmitted from the O / E circuit 105b.
  • the signal is converted into a format suitable for communication with a device connected to the port 102b (for example, Ethernet) and output to the port 102b.
  • the monitoring circuit 107b monitors the number of bit errors in the Demapper 103b, and the observed information is transmitted to the monitoring information reception INF 109a of the transmission side node via the monitoring information transmission INF 106b. If there is an error between the chromatic dispersion compensation amount given in advance at the transmission side node and the chromatic dispersion amount possessed by the communication channel 101c, a large amount of bit errors are observed in the Demapper 103b, and the information is immediately sent to the optimization circuit 1010a. Is fed back.
  • FIGS. 4A and 4B show an operation example of the optimization circuit 1010a
  • FIG. 5 shows a flowchart of the operation.
  • the vertical axis in FIG. 4 represents the number of bit error corrections (number of bit errors) per unit time in error correction processing of an error correction code (for example, FEC), and the horizontal axis represents chromatic dispersion.
  • 4A and 4B show characteristics in which the number of bit errors continuously changes in accordance with the amount of chromatic dispersion compensation. It is known that when a sufficient number of bit errors are generated or when a number of bit errors for a long period that allows a sufficient number of bit errors to be observed, the characteristics generally change parabolically.
  • the optimization circuit 1010a starts training from the initial set value ⁇ t (0) toward ⁇ t (n + 1) or ⁇ t (n ⁇ 1).
  • steps 512-514 the direction in which chromatic dispersion is scanned is determined.
  • step 505 the total number of bit errors in ⁇ t (i) and the total number of bit errors in ⁇ t (i + flag) during the convergence determination time ⁇ T are compared. At this time, if the total number of bit errors of ⁇ t (i + flag) is smaller than the total number of bit errors of ⁇ t (i), step 505 is performed again through step 504.
  • ⁇ t (i) is the value of ⁇ t (i + flag) used in the previous step.
  • the process proceeds to step 506.
  • the total bit error count determination time at this time is ⁇ T
  • the processing after step 506 is processing related to tracking. Usually, the optical fiber is subjected to various external factors (for example, temperature change) even after being laid.
  • the optimum value selection by fine adjustment that is continued after the optimum value selection (coarse adjustment) by training is performed by tracking.
  • a change step ⁇ D2 of chromatic dispersion in tracking is set. This process may be performed simultaneously with step 501, and ⁇ D2 set at this time is preferably smaller than ⁇ D1 set in step 501.
  • steps 510 and 511 the total number of bit errors in each of ⁇ t (ii ⁇ 1), ⁇ t (ii), and ⁇ t (ii + 1) is compared.
  • ⁇ t (ii) when step 510 is performed again is the chromatic dispersion in which the total number of bit errors is the smallest among ⁇ t (ii ⁇ 1), ⁇ t (ii), and ⁇ t (ii + 1) performed immediately before. Is set to a value.
  • the operation at this time is shown in FIG. In this way, by constantly feeding back the number of bit errors of the receiving side node to the transmitting side node, the control works so as to minimize the number of bit errors in the receiving side node, and as a result, the wavelength dispersion is always compensated.
  • a communication system can be constructed.
  • the above optimization operation is performed by sequentially changing the chromatic dispersion compensation amount in a predetermined step in order from the initial setting value ⁇ t (0) and acquiring the number of bit errors at that time within a certain range.
  • This is a method for estimating the chromatic dispersion compensation amount that minimizes the number of bit errors.
  • the method for estimating the minimum number of bit errors is not limited to this method, and the following method can also be adopted. That is, as described above, it is known that the number of bit errors with respect to the amount of chromatic dispersion compensation generally changes continuously in a parabolic manner in a situation where a sufficient number of bit errors has occurred.
  • the relationship between the amount of chromatic dispersion compensation and the number of bit errors can be expressed by a function such as a quadratic function.
  • the quadratic function is estimated from some chromatic dispersion compensation amounts and the number of bit errors corresponding thereto, and the minimum value of the number of bit errors and the chromatic dispersion compensation amount in that case are calculated backward from the estimated quadratic function. Methods can also be employed. Alternatively, the following method can also be adopted.
  • an n-order polynomial is estimated from a chromatic dispersion compensation amount and the number of bit errors corresponding thereto using a method such as Lagrange interpolation, and the minimum value of the number of bit errors and the wavelength in that case are estimated from the estimated polynomial.
  • the dispersion compensation amount is calculated backward (FIG. 10).
  • the interpolation method is not limited to the Lagrangian interpolation method.
  • the above optimization operations may be combined. That is, at the initial stage of training for transmission start, the optimum chromatic dispersion compensation amount is quickly obtained by the method of performing polynomial estimation shown in FIG. 10, and then the chromatic dispersion compensation amount is trained and tracked by the method shown in FIGS.
  • the first embodiment is configured as described above, the following effects can be obtained. That is, it is possible to provide a chromatic dispersion precompensation optical communication system capable of accurately and automatically compensating for chromatic dispersion of an optical fiber transmission line while suppressing circuit scale and power consumption.
  • chromatic dispersion compensation is performed by digital signal processing after converting a signal into an electrical signal, a DCF required for related technology is not required, and a flexible network design is possible.
  • the bit error number information is fed back to the transmitting side node, and the chromatic dispersion compensation amount is adaptively controlled based on the feedback information.
  • the optical reception module can be reduced in size. Also, since the received signal at the receiving side node becomes a signal after chromatic dispersion compensation, it becomes easy to compare the optical waveform at the receiving side node with the optical waveform at the transmitting side node.
  • FIG. 8 is a flowchart (2) of the optimization circuit of the second embodiment of the present invention.
  • ⁇ D1 is a training dispersion step width
  • ⁇ D2 is a tracking dispersion step width
  • flag is a training scanning direction flag
  • t (i) and t (ii) are chromatic dispersion compensation amounts
  • ErrorTh is shifted from tracking to training.
  • Error threshold for This embodiment is different from the flow of FIG. 5 in that a flow for returning to training again according to a predetermined condition after transition to tracking is added in the first embodiment. This assumes that the chromatic dispersion amount is greatly shifted due to path switching or the like in the operating state.
  • FIG. 1 is a training dispersion step width
  • ⁇ D2 is a tracking dispersion step width
  • flag is a training scanning direction flag
  • t (i) and t (ii) are chromatic dispersion compensation amounts
  • ErrorTh is shifted from tracking to training.
  • Error threshold for This embodiment is different from the flow of FIG. 5 in that a flow for returning to training again according
  • the total number of bit errors (Error0) of the previous determination time ⁇ T and the error1 of the latest determination time ⁇ T are compared (step 814). If the difference is equal to or greater than a certain value (ErrorTh), initialization is performed (step 816, 817) Re-enter the training state. In other words, the state immediately before step 512 is restored.
  • an error occurs between the chromatic dispersion compensation amount given in advance by the transmission side node and the chromatic dispersion amount possessed by the communication path 101c, and a situation occurs in which a large amount of bit errors occur in the Demapper 103b. If this happens, it operates as follows. That is, the optimal value search is performed again from the fine adjustment state by tracking to the coarse adjustment stage again by training. This makes it possible to follow a large change in the wavelength dispersion characteristics of the optical fiber. (Third embodiment) In the first embodiment, the amount of chromatic dispersion is adjusted by detecting the number of bit errors at the receiving side node and feeding it back to the transmitting side node.
  • a method is described in which the chromatic dispersion compensation amount is adjusted by directly detecting the chromatic dispersion amount at the receiving side node and feeding back to the transmitting side node instead of detecting the number of bit errors.
  • a basic configuration of this embodiment is shown in FIG. An operation when an optical signal is transmitted from the transmission side node 701a to the reception side node 701b in FIG. 7 will be described.
  • the description will be divided into two steps: roughly measuring the chromatic dispersion of the transmission line and conducting the main signal. First, steps for measuring the approximate chromatic dispersion of the transmission line will be described.
  • the E / O circuit 708a of the transmission side node 701a transmits optical pulse waves having a plurality of wavelengths toward the 701b at the same time.
  • the optical pulse transmitted from the transmission side node 701a is received by the dispersion measuring device 705b of the reception side node 701b.
  • the dispersion measuring device 705b a difference in time required for propagation of the two pulses incident on the transmission side node 701a is measured. Since an equation for calculating approximate chromatic dispersion of a transmission line using a propagation time difference between optical signals of different wavelengths is generally known, description thereof is omitted in this section. In this way, the approximate chromatic dispersion amount of the transmission line for the desired wavelength can be calculated.
  • This value is monitored by the monitoring circuit 707b and appropriately fed back from the monitoring information transmission INF 706b to the transmission side node 101a.
  • the fed back information is received by the monitoring information reception INF 709a, and the chromatic dispersion is more accurately compensated by the coefficient calculation circuit 7011a based on the information, that is, the approximate chromatic dispersion amount of the transmission path.
  • a coefficient is calculated.
  • the E / O circuit 708a switches from the step of measuring chromatic dispersion to the step of conducting the main signal. Next, the step of conducting the main signal will be described.
  • the E / O circuit 708a it is not necessary to output pulses of a plurality of wavelengths by the E / O circuit 708a as in the above-described step. Further, there is no need to measure chromatic dispersion with the dispersion measuring device 705b.
  • the signal input from the port 702a is transmitted to the receiving side node through the mapper 703a, the Fourier transform circuit 705a, the coefficient multiplication circuit 706a, the inverse Fourier transform circuit 707a, and the E / O circuit 708a. Note that the basic operation of these blocks in this step is the same as in the first embodiment, and is omitted in this section. For the same reason, the operations of the O / E circuit 704b and the Demapper 703b are also omitted.
  • the number of bit errors detected by the Demapper 703b is transmitted to the monitoring circuit 707b, and the number of bit errors is constantly monitored by the monitoring circuit 707b.
  • the operation when a large error occurs between the chromatic dispersion compensation amount given in advance by the transmission side node and the chromatic dispersion amount possessed by the communication channel 101c, and a large number of bit errors are observed in the Demapper 103b will be described.
  • the process proceeds to the E / O circuit 708a via the dispersion measuring device 705b, the monitoring information transmission INF 706b, and the monitoring information reception INF 709a.
  • a switching instruction is transmitted.
  • the E / O circuit 708a and the dispersion measuring device 705b re-shift from the step of conducting the main signal to the step of measuring chromatic dispersion. After the chromatic dispersion measurement, the process shifts again to the step of conducting the main signal.
  • the third embodiment a technique for directly detecting the chromatic dispersion amount at the reception side node, adjusting the chromatic dispersion compensation amount by feeding back to the transmission side node, and conducting the main signal after the adjustment is completed. It was described. However, the tracking operation described in the first embodiment may be performed after the main signal is turned on after the adjustment is completed.
  • FIG. 9 is a diagram of a chromatic dispersion precompensated optical communication system according to a fourth embodiment of the present invention.
  • the chromatic dispersion precompensation optical communication transmitting / receiving apparatus 901 of the fourth embodiment includes a decomposition unit 902 that decomposes a signal to be transmitted for each frequency component, a calculation unit 903 that calculates a delay amount to be added to each of the frequency components, Have Further, the chromatic dispersion pre-compensation optical communication transmitting / receiving apparatus 901 combines a delay unit 904 that delays each frequency component based on the delay amount, and a combined transmission unit that combines the delayed signals and sends the combined signals to a transmission line. 905.
  • the fourth embodiment described above it is possible to provide a chromatic dispersion pre-compensation optical communication system capable of accurately and automatically compensating for the chromatic dispersion of the optical fiber transmission line.
  • the number of error correction bits (number of bit errors) per unit time in error correction processing is used as transmission quality information, but the present invention is not limited to this.
  • a BER Bit Error rate
  • FER Frame Error rate
  • CRC Cyclic Redundancy Check
  • a dedicated device is assumed, but the following may be used. That is, for example, a personal computer device that performs various data processing is loaded with a board or a card that performs processing corresponding to this example, and each processing is executed on the computer device side. In this way, a configuration may be adopted in which software for executing the processing is installed in a personal computer device and executed.
  • the program installed in the data processing device such as the personal computer device may be distributed via various recording (storage) media such as an optical disk and a memory card, or distributed via communication means such as the Internet. Also good.
  • (Appendix 1) Decomposition means for decomposing the signal to be transmitted for each frequency component; Calculating means for calculating a delay amount to be added to each of the frequency components; Delay means for delaying each frequency component based on the delay amount; A combined transmission means for combining the delayed signals and sending the combined signals to the transmission line as a combined transmission signal; A chromatic dispersion precompensated optical communication transmitter / receiver comprising: (Appendix 2) A transmission evaluation value receiving means for receiving a transmission evaluation value returned from the receiving side that has received each of the combined transmission signals; The calculation means calculates a delay amount group that is a combination of delay amounts to be added to each of the frequency components from the transmission evaluation value, The delay means delays each of the frequency components by the delay amount group of a predetermined plurality of combinations, The
  • the chromatic dispersion precompensated optical communication transmitter / receiver according to supplementary note 1, wherein: (Appendix 3) The transmission evaluation value is the number of bit errors on the receiving side that received each of the combined transmission signals.
  • the delay amount group is changed by a predetermined amount until the number of bit errors is minimized, Reducing the predetermined amount after the number of bit errors is minimized;
  • the delay amount group is a best value of the transmission evaluation value in a predetermined function that approximates a relationship of the transmission evaluation value to the chromatic dispersion
  • the chromatic dispersion precompensated optical communication transmitter / receiver according to any one of appendix 2 to appendix 5, wherein (Appendix 7)
  • the predetermined function is a quadratic function, and the number of the plurality of predetermined combinations is three.
  • the delay amount group is changed until the delay dispersion at the receiving side that has received each of the combined transmission signals is minimized.
  • the chromatic dispersion precompensated optical communication transmitting / receiving apparatus according to any one of appendix 2 to appendix 7, wherein (Appendix 9)
  • the chromatic dispersion precompensation optical communication transmitter / receiver according to any one of appendices 1 to 8, and a chromatic dispersion precompensation optical communication transmitter / receiver on a receiving side installed opposite to the chromatic dispersion precompensation optical communication transmitter / receiver, Prepared,
  • the chromatic dispersion pre-compensation optical communication system wherein the reception-side chromatic dispersion pre-compensation optical communication transceiver receives each of the combined transmission signals and returns a transmission evaluation value.
  • (Appendix 11) Receiving a transmission evaluation value returned from the receiving side that received each of the combined transmission signals; Calculate an optimal delay amount group that is a combination of delay amounts to be added to each of the frequency components from the transmission evaluation value, Each of the frequency components is delayed by a predetermined plurality of combinations of the delay amount groups, Combining each delayed frequency component for each of the plurality of combinations and sending it to a transmission line as a combined transmission signal;
  • the chromatic dispersion precompensated optical communication transmission / reception method as set forth in appendix 10, wherein: (Appendix 12)
  • the transmission evaluation value is the number of bit errors on the receiving side that received each of the combined transmission signals.
  • the chromatic dispersion precompensated optical communication transmission / reception method as set forth in appendix 11, wherein: (Appendix 13) Changing the delay amount group until the number of bit errors is minimized;
  • the chromatic dispersion precompensated optical communication transmission / reception method as set forth in appendix 12, wherein: (Appendix 14) The delay amount group is changed by a predetermined amount until the number of bit errors is minimized, Reducing the predetermined amount after the number of bit errors is minimized; 14.
  • the chromatic dispersion precompensated optical communication transmitting / receiving method according to appendix 12 or appendix 13.
  • the delay amount group is a best function of the transmission evaluation value in a predetermined function that approximates the relationship of the transmission evaluation value to the chromatic dispersion amount of the transmission line corresponding to each of the delay amount groups of the predetermined plurality of combinations. Calculated as a delay amount group corresponding to the chromatic dispersion amount giving the value 15.
  • the chromatic dispersion precompensated optical communication transmission / reception method according to any one of appendix 11 to appendix 14, wherein: (Appendix 16)
  • the predetermined function is a quadratic function, and the number of the plurality of predetermined combinations is three.
  • the chromatic dispersion precompensated optical communication transmission / reception method characterized by: (Appendix 17) The delay amount group is changed by a constant amount until delay dispersion at the receiving side that has received each of the combined transmission signals is minimized.
  • the chromatic dispersion precompensated optical communication transmitting / receiving method according to any one of Supplementary Note 11 to Supplementary Note 16, wherein: This application claims the priority on the basis of Japanese application Japanese Patent Application No. 2011-067671 for which it applied on March 25, 2011, and takes in those the indications of all here.
  • the present invention relates to an optical communication system that compensates for chromatic dispersion in advance, and has industrial applicability.

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  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Optical Communication System (AREA)

Abstract

La présente invention a pour objectif de proposer un système de communication optique à pré-compensation de dispersion en longueur d'onde apte à compenser, de façon automatique et précise, une dispersion en longueur d'onde de voies de transmission par fibre optique. Afin d'atteindre cet objectif, la présente invention se rapporte à un appareil émetteur-récepteur radio de communication optique à pré-compensation de dispersion en longueur d'onde comprenant : des moyens de décomposition, pour décomposer un signal, qui doit être transmis, en composantes de fréquence ; des moyens de calcul, pour calculer la grandeur d'un retard devant être ajouté à chacune des composantes de fréquence ; des moyens à retard, pour retarder chacune des composantes de fréquence sur la base de la grandeur du retard ; et des moyens de combinaison/transmission, pour combiner les signaux retardés et pour envoyer les signaux combinés à une voie de transmission.
PCT/JP2012/058043 2011-03-25 2012-03-21 Système de communication optique à pré-compensation de dispersion en longueur d'onde WO2012133473A1 (fr)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2012124782A (ja) * 2010-12-09 2012-06-28 Fujitsu Ltd デジタルコヒーレント光受信器、適応等化型イコライザ及びデジタルコヒーレント光通信方法
CN105917605A (zh) * 2014-02-04 2016-08-31 华为技术有限公司 利用色散预补偿数字信号处理的直接检测正交频分复用

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2010137113A1 (fr) * 2009-05-26 2010-12-02 三菱電機株式会社 Appareil émetteur à pré-égalisation et système d'émission à pré-égalisation
WO2010150356A1 (fr) * 2009-06-23 2010-12-29 三菱電機株式会社 Système d'accès optique, appareil terminal côté station et appareil terminal côté abonné

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2010137113A1 (fr) * 2009-05-26 2010-12-02 三菱電機株式会社 Appareil émetteur à pré-égalisation et système d'émission à pré-égalisation
WO2010150356A1 (fr) * 2009-06-23 2010-12-29 三菱電機株式会社 Système d'accès optique, appareil terminal côté station et appareil terminal côté abonné

Non-Patent Citations (3)

* Cited by examiner, † Cited by third party
Title
ALAN BARBIERI ET AL.: "OFDM versus Single- Carrier Transmission for 100 Gbps Optical Communication", JOURNAL OF LIGHTWAVE TECHNOLOGY, vol. 28, no. ISSUE., 1 September 2010 (2010-09-01), pages 2537 - 2551, XP011312257 *
FRED BUCHALI ET AL.: "Adaptive PMD compensation by electrical and optical techniques", JOURNAL OF LIGHTWAVE TECHNOLOGY, vol. 22, no. ISSUE., April 2004 (2004-04-01), pages 1116 - 1126, XP011111648, DOI: doi:10.1109/JLT.2004.825893 *
LAKSHMI P.BASKARAN ET AL.: "Transmitter Pre- emphasis and Adaptive Receiver Equalization for Duobinary Signaling in Backplane Channels", INTERNATIONAL CONFERENCE ON CONSUMER ELECTRONICS, 2007. ICCE 2007. DIGEST OF TECHNICAL PAPERS, 10 January 2007 (2007-01-10), pages 1 - 2, XP031071421 *

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2012124782A (ja) * 2010-12-09 2012-06-28 Fujitsu Ltd デジタルコヒーレント光受信器、適応等化型イコライザ及びデジタルコヒーレント光通信方法
US8989602B2 (en) 2010-12-09 2015-03-24 Fujitsu Limited Digital coherent optical receiver, adaptive equalizer, and digital coherent optical communication method
CN105917605A (zh) * 2014-02-04 2016-08-31 华为技术有限公司 利用色散预补偿数字信号处理的直接检测正交频分复用
EP3100388A4 (fr) * 2014-02-04 2017-02-15 Huawei Technologies Co., Ltd. Multiplexage par répartition orthogonale de la fréquence à détection directe avec traitement de signal numérique pour pré-compensation de la dispersion
US9641374B2 (en) 2014-02-04 2017-05-02 Huawei Technologies Co., Ltd. Direct-detected orthogonal frequency-division multiplexing with dispersion pre-compensation digital signal processing

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