WO2014155775A1 - 信号処理装置、光通信システム、及び信号処理方法 - Google Patents
信号処理装置、光通信システム、及び信号処理方法 Download PDFInfo
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- WO2014155775A1 WO2014155775A1 PCT/JP2013/075231 JP2013075231W WO2014155775A1 WO 2014155775 A1 WO2014155775 A1 WO 2014155775A1 JP 2013075231 W JP2013075231 W JP 2013075231W WO 2014155775 A1 WO2014155775 A1 WO 2014155775A1
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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
- H04B10/60—Receivers
- H04B10/61—Coherent receivers
- H04B10/616—Details of the electronic signal processing in coherent optical receivers
- H04B10/6161—Compensation of chromatic dispersion
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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
-
- 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
- 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
- H04B10/613—Coherent receivers including phase diversity, e.g., having in-phase and quadrature branches, as in QPSK coherent receivers
-
- 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
- H04B10/614—Coherent receivers comprising one or more polarization beam splitters, e.g. polarization multiplexed [PolMux] X-PSK coherent receivers, polarization diversity heterodyne coherent receivers
-
- 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
- H04B10/6163—Compensation of non-linear effects in the fiber optic link, e.g. self-phase modulation [SPM], cross-phase modulation [XPM], four wave mixing [FWM]
-
- 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
- H04B10/6165—Estimation of the phase of the received optical signal, phase error estimation or phase error correction
Definitions
- the present invention relates to a signal processing apparatus and a signal processing method used for optical communication.
- the amount of data to be communicated is increasing with the spread of the Internet. In order to cope with this, it is necessary to increase the capacity of the transmission path.
- One technique for realizing a large capacity is a multilevel modulation method (Quadrature Amplitude Modulation: QAM).
- QAM Quadrature Amplitude Modulation
- the optical signal that has been subjected to QAM modulation by the transmitter is demodulated by a digital coherent optical receiver.
- This compensation method is a method for compensating for waveform distortion while tracing the propagation waveform from the reception side to the transmission side by performing dispersion compensation in small steps and performing nonlinear compensation immediately after each dispersion compensation.
- the dispersion compensation function is realized by a linear distortion compensation circuit
- the nonlinear compensation function is realized by a nonlinear distortion compensation circuit.
- the linear distortion compensation circuit includes an FFT / IFFT circuit in order to perform dispersion compensation in the frequency domain. Since the FFT / IFFT circuit has a large circuit scale, only a few FFT / IFFT circuits can be mounted on one signal processing device in consideration of the LSI mounting area and power consumption.
- Non-Patent Document 1 describes a compensation method called Filtered Back Propagation.
- Filtered Back Propagation uses the time average amount of the phase rotation amount calculated from the signal intensity for nonlinear compensation, thereby reducing the number of stages of the nonlinear compensation stage.
- Non-Patent Document 2 describes Perturbation Back Propagation as a method of further reducing the number of nonlinear compensation stages.
- the non-linear compensation stage can be reduced to, for example, three stages by canceling the phase rotation caused by the perturbation component in addition to the cancellation of the phase rotation caused by the signal intensity described above.
- a circuit that converts a received optical signal into an electrical signal and processes it is generally incorporated in a semiconductor device. For this reason, it is important to reduce the circuit for processing signals in order to suppress an increase in the size of the semiconductor device.
- Filtered Back Propagation can reduce the number of stages of nonlinear compensation stages, it can suppress the increase in size of semiconductor devices.
- the number of stages of the nonlinear compensation stage needs to be a certain number or more.
- the present inventor has studied reducing the size of the semiconductor device without reducing the number of nonlinear compensation stages.
- An object of the present invention is to provide a signal processing device and an optical communication system that can reduce the size of a semiconductor device without reducing the number of stages of nonlinear compensation stages.
- electrical signal generating means for generating an electrical signal based on signal light that has been polarization multiplexed and multi-level modulated and transmitted via a transmission line;
- First phase compensation means for performing phase rotation compensation processing on the electrical signal;
- Distortion compensation means for performing dispersion compensation processing and phase rotation compensation processing at least once in this order on the electric signal after compensation by the first phase compensation means;
- a signal processing apparatus is provided.
- an optical transmitter for transmitting an optical signal;
- An optical receiver for receiving the optical signal via a transmission line;
- the optical transmitter is Optical signal generation means for generating the optical signal by polarization multiplexing and multi-level modulation of light,
- One of the optical transmitter and the optical receiver includes first dispersion compensation means for performing dispersion compensation on the signal light by an optical method,
- the optical receiver is An electric signal generating means for generating an electric signal based on the signal light after being compensated by the first dispersion compensating means;
- First phase compensation means for performing phase rotation compensation processing on the electrical signal;
- An optical communication system is provided.
- an optical transmitter for transmitting an optical signal;
- An optical receiver for receiving the optical signal via a transmission line;
- the optical transmitter is First dispersion compensation means for performing dispersion compensation processing on a signal before being converted into the optical signal;
- Optical signal generation means for generating the optical signal by modulating light using the signal after being compensated by the first dispersion compensation means;
- the optical receiver is An electric signal generating means for generating an electric signal based on the signal light;
- First phase compensation means for performing phase rotation compensation processing on the electrical signal;
- An optical communication system is provided.
- the step of receiving polarization multiplexed and multilevel modulated signal light via a transmission line Generating an electrical signal based on the signal light; Performing phase rotation compensation processing on the electrical signal; Performing dispersion compensation processing and phase rotation compensation processing in this order on the electrical signal after being compensated by the first phase compensation means;
- a signal processing method is provided in which a part of the dispersion amount of the signal light in the transmission path is compensated.
- FIG. 1 is a diagram illustrating a configuration of an optical communication system according to the first embodiment.
- the optical communication system according to the present embodiment includes an optical transmission device 10 and an optical reception device 20.
- the optical transmitter 10 and the optical receiver 20 are connected to each other via a transmission path 30.
- the transmission path 30 is configured using an optical fiber or the like.
- This optical communication system is a system that performs communication using, for example, a QAM (Quadrature Amplitude Modulation) method.
- QAM Quadrature Amplitude Modulation
- the optical transmitter 10 generates a polarization multiplexed optical signal by modulating and multiplexing light using a plurality of signals to be transmitted.
- the generated optical signal is transmitted to the optical receiver 20 via the transmission path 30.
- the optical receiver 20 demodulates the received optical signal. When the optical signal propagates through the transmission path 30, it undergoes a linear effect (dispersion effect) and a nonlinear effect.
- the optical receiver 20 also performs processing for compensating for these effects.
- FIG. 2 is a diagram illustrating an example of a functional configuration of the optical receiver 20.
- the optical receiver 20 includes an electrical signal generation unit 200, a first phase compensation unit 101, a distortion compensation unit 102, and a first dispersion compensation unit 400.
- the electric signal generation unit 200 generates an electric signal based on the received signal light.
- the first phase compensation unit 101 performs phase rotation compensation processing on the electrical signal generated by the electrical signal generation unit 200.
- the distortion compensator 102 performs the dispersion compensation process and the phase rotation compensation process at least once in this order on the electrical signal after compensation by the first phase compensation unit.
- the electric signal generation unit 200, the first phase compensation unit 101, and the distortion compensation unit 102 are incorporated in one semiconductor device.
- the optical receiver 20 further includes a first dispersion compensation unit 400.
- the first dispersion compensation unit 400 performs dispersion compensation on the signal light transmitted from the optical transmission device 10 by an optical method.
- the electrical signal generation unit 200 generates an electrical signal based on the signal light after the first dispersion compensation unit 400 performs dispersion compensation.
- the sum of the dispersion compensation amount by the distortion compensation unit 102 and the dispersion compensation amount by the first dispersion compensation unit 400 is equal to the dispersion amount received by the signal light in the transmission path 30.
- the dispersion amount received by the signal light in the transmission path 30 is measured or calculated, and the dispersion compensation amount and the first dispersion compensation in the first phase compensation unit 101 are made equal to the dispersion amount.
- a dispersion compensation amount by the unit 400 may be set.
- the first dispersion compensation unit 400 and the first phase compensation unit 101 constitute the first nonlinear compensation stage.
- the second and subsequent nonlinear compensation stages are configured by the distortion compensation unit 102. Therefore, the number of electrical circuits required to configure a plurality of nonlinear compensation stages is reduced by one dispersion compensation unit. Therefore, the number of circuits incorporated in the semiconductor device can be reduced, and as a result, the semiconductor device can be reduced in size. In other words, the number of nonlinear compensation stages can be increased without increasing the size of the semiconductor device.
- the optical communication system according to the present embodiment has the same configuration as that of the optical communication system according to the first embodiment, except for the configuration of the optical receiver 20.
- FIG. 3 is a diagram showing a functional configuration of the optical receiver 20 according to the present embodiment.
- the optical receiver 20 includes a first dispersion compensation unit 400, a local light source (LO) 210, an optical 90 ° hybrid 220 (interference unit), a photoelectric (O / E) conversion unit 230, an AD (analog / digital) conversion unit (ADC). ) 240 and the signal processing unit 100.
- the signal processing unit 100 is composed of one semiconductor device.
- the first dispersion compensation unit 400 performs dispersion compensation on the signal light transmitted from the optical transmission device 10 by an optical method.
- the light 90 ° hybrid 220 receives the signal light after dispersion compensation by the first dispersion compensation unit 400 and the local light from the local light source 210.
- the optical 90 ° hybrid 220 generates a first optical signal (I x ) by causing an optical signal and local light to interfere with each other with a phase difference of 0, and causes the optical signal and local light to interfere with each other with a phase difference of ⁇ / 2.
- Two optical signals (Q x ) are generated.
- the optical 90 ° hybrid 220 generates a third optical signal (I y ) by causing the optical signal and local light to interfere with each other with a phase difference of 0, and causes the optical signal and local light to interfere with each other with a phase difference of ⁇ / 2.
- a fourth optical signal (Q y ) is generated.
- the first optical signal and the second optical signal form a set of signals
- the third optical signal and the fourth optical signal also form a set of signals.
- the photoelectric conversion unit 230 photoelectrically converts the four optical signals (output light) generated by the light 90 ° hybrid 220 to generate four analog signals.
- the AD converter 240 converts each of the four analog signals generated by the photoelectric converter 230 into digital signals (quantization).
- the signal processing unit 100 processes the four digital signals generated by the AD conversion unit 240 to generate a demodulated signal obtained by demodulating the optical signal.
- the signal processing unit 100 includes a polarization signal generation unit 110, a first phase compensation unit 101, a distortion compensation unit 102, a polarization separation unit 104, and a demodulation unit 106.
- the polarization signal generation unit 110 includes addition units 112 and 114.
- the adder 112 adds the digital signal generated from the first optical signal (I x ) and the digital signal generated from the second optical signal (Q x ), thereby performing the first polarization signal (E x ).
- the adder 114 adds the digital signal generated from the third optical signal (I y ) and the digital signal generated from the fourth optical signal (Q y ), thereby performing the second polarization signal (E y ).
- Ex and Ey follow the following formulas (1) and (2).
- the first phase compensation unit 101 performs phase compensation on the first polarization signal (E x ) and the second polarization signal (E y ).
- the distortion compensator 102 performs processing for compensating for the linear effect and the nonlinear effect received when the optical signal propagates through the transmission path 30. Details of the first phase compensation unit 101 and the distortion compensation unit 102 will be described later.
- the polarization separation unit 104 performs a filter operation for each polarization.
- the demodulator 106 demodulates the transmitted signal by compensating for the frequency difference and phase difference between the optical signal and the local light.
- FIG. 4 is a diagram for explaining a functional configuration of the distortion compensation unit 102.
- the distortion compensation unit 102 has at least one processing stage including a linear compensation unit 301 and a nonlinear compensation unit 300.
- the final stage of the distortion compensation unit 102 is preferably the linear compensation unit 301 (second dispersion compensation unit).
- the number of processing stages is 10 or more, for example, the final stage of the distortion compensation unit 102 may not be the linear compensation unit 301.
- the dispersion compensation amount and the first dispersion by the linear compensation unit 301 included in the distortion compensation unit 102 are the same.
- the sum of the dispersion compensation amounts by the compensation unit 400 is equal to the dispersion amount received by the signal light in the transmission path 30.
- the linear compensation unit 301 compensates for the linear effect that the optical signal has received on the transmission path 30.
- the linear compensation unit 301 includes, for example, an FFT (Fast Fourier Transform) unit, a filter unit, and an IFFT (Inverse Fast Fourier Transform) unit.
- the FFT unit performs an FFT operation on the input signal.
- the filter unit performs a filter operation on the signal using a filter coefficient for compensating for the dispersion effect that the optical signal receives in the transmission path.
- the IFFT unit performs an IFFT operation on the filtered signal.
- the non-linear compensation unit 300 compensates for the non-linear effect that the optical signal has received on the transmission path 30.
- FIG. 5 is a diagram illustrating an example of a functional configuration of the first phase compensation unit 101.
- the functional configuration of the nonlinear compensator 300 is the same as the configuration shown in FIG.
- the first phase compensation unit 101 performs compensation processing according to Filtered Back Propagation.
- the first phase compensation unit 101 may perform processing according to another method, for example, processing according to Back Propagation or Perturbation Back Propagation.
- the first phase compensation unit 101 includes intensity calculation units 302 and 304, an addition unit 305, a filter unit 306, a phase modulation unit 308, delay units 310 and 314, and multiplication units 312 and 316.
- Strength calculating unit 302 calculates the intensity of the polarized signal E x, and calculates the phase rotation amount based on the intensity.
- the intensity calculation unit 304 calculates the intensity of the polarization signal E y and calculates the amount of phase rotation based on the intensity.
- the addition unit 305 adds the phase rotation amount calculated by the intensity calculation unit 302 and the phase rotation amount calculated by the intensity calculation unit 304.
- the filter unit 306 multiplies the phase rotation amount output from the adding unit 305 by a coefficient (h (n)) for time averaging.
- the phase modulation unit 308 uses the phase rotation amount after being processed by the filter unit 306 to calculate a coefficient for compensating for the phase rotation. Then, this coefficient is multiplied by the polarization unit E x after being delayed by the delay unit 310 by the multiplication unit 312, and the polarization signal E y after being delayed by the delay unit 314 by the multiplication unit 316. Is multiplied. Note that the delay units 310 and 314 are provided to synchronize the polarization signals E x and E y with the coefficient calculation timing.
- the first phase compensation unit 101 shown in FIG. 5 performs processing according to the following equations (3) and (4).
- FIG. 6 shows the relationship between the number of stages of the nonlinear compensation stage and the improvement amount of the transmission quality Q value.
- BP Back Propagation
- FBP Filtered Back Propagation
- n the greater the effect of nonlinear compensation.
- the number of nonlinear compensation stages is preferably 5 or less.
- the Q value is improved in a linear function as n increases. That is, it can be seen that the improvement amount of the Q value varies greatly depending on the presence or absence of one nonlinear compensation stage.
- the number of stages of the nonlinear guarantee stage can be increased without increasing the size of the semiconductor device.
- FIG. 7 is a diagram illustrating a functional configuration of the optical transmission device 10 used in the optical communication system according to the third embodiment
- FIG. 8 is a diagram illustrating a functional configuration of the optical reception device 20 according to the present embodiment. is there.
- the optical transmission device 10 has the first dispersion compensation unit 570 instead of the optical reception device 20 not having the first dispersion compensation unit 400.
- the configuration is the same as that of the optical communication system according to the second embodiment.
- the optical transmission apparatus 10 includes a data generation unit 500, a mapping unit 520, a DA (digital / analog) conversion unit (DAC) 540, an electro-optical conversion (E / O) unit 560, and a first dispersion compensation unit 570.
- the data generation unit 500 generates a plurality of signals (multiple digit binary signals) to be transmitted.
- the mapping unit 520 performs mapping processing to determine to which position in the constellation of the QAM signal the signal generated by the data generation unit 500 is allocated. Thereby, two polarization signals E x and E y in which a plurality of signals are assigned to the multilevel signal are generated.
- the DA converter 540 converts the two polarization signals E x and E y into analog signals.
- the electro-optical conversion unit 560 includes a laser light source, an optical modulator, and a polarization multiplexing unit, and modulates the light output from the laser light source with two analog signals generated by the DA conversion unit 540 to perform polarization multiplexing. By doing so, an optical signal to be transmitted is generated.
- the first dispersion compensation unit 570 performs processing for compensating in advance a part of dispersion received on the transmission path 30 for the optical signal generated by the electro-optic conversion unit 560.
- the sum of the dispersion compensation amount by the first dispersion compensation unit 570 and the dispersion compensation amount by the distortion compensation unit 102 is equal to the dispersion amount received by the signal light in the transmission path 30.
- the optical communication system according to the present embodiment has the same configuration as that of the optical communication system according to the third embodiment, except for the functional configuration of the optical transmission device 10.
- FIG. 9 is a diagram illustrating a functional configuration of the optical transmission device 10 according to the present embodiment.
- the optical transmission device 10 shown in the figure includes a first dispersion compensation unit 580 instead of the first dispersion compensation unit 570 shown in FIG. 7, and does not perform dispersion compensation optically but performs signal processing. Is going.
- the first dispersion compensation unit 580 performs dispersion compensation processing on the two polarization signals E x and E y output from the mapping unit 520.
- the DA converter 540 converts the two polarization signals after the first dispersion compensator 580 performs the dispersion process into analog signals.
- the electro-optical conversion unit 560 modulates light using the two analog signals generated by the DA conversion unit 540 to generate signal light.
- An electric signal generating means for generating an electric signal based on signal light that is polarization multiplexed and multi-level modulated and transmitted via a transmission line; First phase compensation means for performing phase rotation compensation processing on the electrical signal; Distortion compensation means for performing dispersion compensation processing and phase rotation compensation processing at least once in this order on the electric signal after compensation by the first phase compensation means;
- a signal processing apparatus comprising: 2.1 In the signal processing apparatus described in 2.1, The signal light includes first dispersion compensation means for performing dispersion compensation by an optical method, The signal processing device, wherein the electric signal generating means generates the electric signal based on the signal light after being compensated by the first dispersion compensating means.
- the sum of the dispersion compensation amount by the distortion compensation means and the dispersion compensation amount by the first dispersion compensation means is a signal processing apparatus equal to the dispersion amount received by the signal light in the transmission path.
- the electrical signal generating means includes Interference means for generating four output lights by causing interference between the signal light and the local light after compensation by the first phase compensation means; Photoelectric conversion means for photoelectrically converting the four output lights to generate four analog signals; Analog-to-digital conversion means for converting the four analog signals into four digital signals; Polarization signal generating means for generating two polarization signals corresponding to two polarization components of the signal light as the electric signal from the four digital signals; A signal processing apparatus.
- a signal processing apparatus comprising second dispersion compensation means that is provided after the distortion compensation means in the final stage and performs dispersion compensation processing on the electrical signal.
- the sum of the dispersion compensation amount by the distortion compensation unit, the dispersion compensation amount by the first dispersion compensation unit, and the dispersion compensation amount by the second dispersion compensation unit is equal to the dispersion amount received by the signal light in the transmission path. apparatus. 7).
- An optical transmitter for transmitting an optical signal;
- An optical receiver for receiving the optical signal via a transmission line;
- the optical transmitter is Optical signal generation means for generating the optical signal by polarization multiplexing and multi-level modulation of light,
- One of the optical transmitter and the optical receiver includes first dispersion compensation means for performing dispersion compensation on the signal light by an optical method,
- the optical receiver is An electric signal generating means for generating an electric signal based on the signal light after being compensated by the first dispersion compensating means;
- First phase compensation means for performing phase rotation compensation processing on the electrical signal;
- An optical communication system comprising: 8).
- An optical transmitter for transmitting an optical signal;
- An optical receiver for receiving the optical signal via a transmission line;
- the optical transmitter is First dispersion compensation means for performing dispersion compensation processing on a signal before being converted into the optical signal;
- Optical signal generation means for generating the optical signal by modulating light using the signal after being compensated by the first dispersion compensation means;
- the optical receiver is An electric signal generating means for generating an electric signal based on the signal light;
- First phase compensation means for performing phase rotation compensation processing on the electrical signal;
- An optical communication system comprising: In the optical communication system according to 9.7 or 8, The optical communication system, wherein the sum of the dispersion compensation amount by the distortion compensation means and the dispersion compensation amount by the first dispersion compensation means is equal to the dispersion amount received by the signal light in the transmission path.
- the electrical signal generating means includes Interference means for generating four output lights by causing interference between the signal light and the local light after compensation by the first phase compensation means; Photoelectric conversion means for photoelectrically converting the four output lights to generate four analog signals; Analog-to-digital conversion means for converting the four analog signals into four digital signals; Polarization signal generating means for generating two polarization signals corresponding to two polarization components of the signal light as the electric signal from the four digital signals; An optical communication system.
- the optical receiving apparatus is an optical communication system provided with second dispersion compensation means that is provided after the distortion compensation means at the final stage and performs dispersion compensation processing on the electrical signal.
- the sum of the dispersion compensation amount by the distortion compensation means, the dispersion compensation amount by the first dispersion compensation means, and the dispersion compensation amount by the second dispersion compensation means is equal to the dispersion amount received by the signal light in the transmission path. system. 13.
- the signal light is a signal processing method in which a part of the dispersion amount in the transmission path is compensated.
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Abstract
Description
前記電気信号に対して位相回転補償処理を行う第1位相補償手段と、
前記第1位相補償手段によって補償された後の前記電気信号に対して分散補償処理及び位相回転補償処理をこの順で少なくとも1回行う歪補償手段と、
を備える信号処理装置が提供される。
伝送路を介して前記光信号を受信する光受信装置と、
を備え、
前記光送信装置は、
光を偏波多重かつ多値変調することにより前記光信号を生成する光信号生成手段を備え、
前記光送信装置及び前記光受信装置の一方は、前記信号光に、光学的方法によって分散補償を行う第1分散補償手段を備え、
前記光受信装置は、
前記第1分散補償手段により補償された後の前記信号光に基づいて電気信号を生成する電気信号生成手段と、
前記電気信号に対して位相回転補償処理を行う第1位相補償手段と、
前記第1位相補償手段によって補償された後の前記電気信号に対して分散補償処理及び位相回転補償処理をこの順で少なくとも一つの歪補償手段と、
を備える光通信システムが提供される。
伝送路を介して前記光信号を受信する光受信装置と、
を備え、
前記光送信装置は、
前記光信号に変換される前の信号に対して分散補償処理を行う第1分散補償手段と、
前記第1分散補償手段によって補償された後の前記信号を用いて光を変調することにより前記光信号を生成する光信号生成手段と、
を備え、
前記光受信装置は、
前記信号光に基づいて電気信号を生成する電気信号生成手段と、
前記電気信号に対して位相回転補償処理を行う第1位相補償手段と、
前記第1位相補償手段によって補償された後の前記電気信号に対して分散補償処理及び位相回転補償処理をこの順で少なくとも一つの歪補償手段と、
を備える光通信システムが提供される。
前記信号光に基づいて電気信号を生成するステップと、
前記電気信号に対して位相回転補償処理を行うステップと、
前記第1位相補償手段によって補償された後の前記電気信号に対して分散補償処理及び位相回転補償処理をこの順で行うステップと、
を備え、
前記電気信号を生成するステップの前において、前記信号光は、前記伝送路における分散量の一部が補償されている信号処理方法が提供される。
図1は、第1の実施形態に係る光通信システムの構成を示す図である。本実施形態に係る光通信システムは、光送信装置10及び光受信装置20を備えている。光送信装置10及び光受信装置20は、伝送経路30を介して互いに接続されている。伝送経路30は、光ファイバなどを用いて構成されている。この光通信システムは、例えばQAM(Quadrature Amplitude Modulation)方式で通信を行うシステムである。
本実施形態に係る光通信システムは、光受信装置20の構成を除いて、第1の実施形態に係る光通信システムと同様の構成である。
図7は、第3の実施形態に係る光通信システムで用いられる光送信装置10の機能構成を示す図であり、図8は、本実施形態に係る光受信装置20の機能構成を示す図である。本実施形態に係る光通信システムは、光受信装置20が第1分散補償部400を有していない代わりに、光送信装置10が第1分散補償部570を有している点を除いて、第2の実施形態に係る光通信システムと同様の構成である。
本実施形態に係る光通信システムは、光送信装置10の機能構成を除いて、第3の実施形態に係る光通信システムと同様の構成である。
1.偏波多重かつ多値変調されていて伝送路を介して送信された信号光に基づいて電気信号を生成する電気信号生成手段と、
前記電気信号に対して位相回転補償処理を行う第1位相補償手段と、
前記第1位相補償手段によって補償された後の前記電気信号に対して分散補償処理及び位相回転補償処理をこの順で少なくとも1回行う歪補償手段と、
を備える信号処理装置。
2.1に記載の信号処理装置において、
前記信号光に、光学的方法によって分散補償を行う第1分散補償手段を備え、
前記電気信号生成手段は、前記第1分散補償手段により補償された後の前記信号光に基づいて前記電気信号を生成する信号処理装置。
3.1又は2に記載の信号処理装置において、
前記歪補償手段による分散補償量と前記第1分散補償手段による分散補償量の和は、前記伝送路において前記信号光が受ける分散量に等しい信号処理装置。
4.1~3のいずれか一つに記載の信号処理装置において、
前記電気信号生成手段は、
前記第1位相補償手段により補償された後の前記信号光と局所光とを干渉させることにより4つの出力光を生成する干渉手段と、
前記4つの出力光を光電変換して4つのアナログ信号を生成する光電変換手段と、
前記4つのアナログ信号を4つのデジタル信号に変換するアナログ・デジタル変換手段と、
前記4つのデジタル信号から、前記信号光の2つの偏波成分に対応する2つの偏波信号を、前記電気信号として生成する偏波信号生成手段と、
を有する信号処理装置。
5.1、2、又は4に記載の信号処理装置において、
最終段の前記歪補償手段の後に設けられており、前記電気信号に対して分散補償処理を行う第2分散補償手段を備える信号処理装置。
6.5に記載の信号処理装置において、
前記歪補償手段による分散補償量、前記第1分散補償手段による分散補償量、及び前記第2分散補償手段による分散補償量の和は、前記伝送路において前記信号光が受ける分散量に等しい信号処理装置。
7.光信号を送信する光送信装置と、
伝送路を介して前記光信号を受信する光受信装置と、
を備え、
前記光送信装置は、
光を偏波多重かつ多値変調することにより前記光信号を生成する光信号生成手段を備え、
前記光送信装置及び前記光受信装置の一方は、前記信号光に、光学的方法によって分散補償を行う第1分散補償手段を備え、
前記光受信装置は、
前記第1分散補償手段により補償された後の前記信号光に基づいて電気信号を生成する電気信号生成手段と、
前記電気信号に対して位相回転補償処理を行う第1位相補償手段と、
前記第1位相補償手段によって補償された後の前記電気信号に対して分散補償処理及び位相回転補償処理をこの順で少なくとも一つの歪補償手段と、
を備える光通信システム。
8.光信号を送信する光送信装置と、
伝送路を介して前記光信号を受信する光受信装置と、
を備え、
前記光送信装置は、
前記光信号に変換される前の信号に対して分散補償処理を行う第1分散補償手段と、
前記第1分散補償手段によって補償された後の前記信号を用いて光を変調することにより前記光信号を生成する光信号生成手段と、
を備え、
前記光受信装置は、
前記信号光に基づいて電気信号を生成する電気信号生成手段と、
前記電気信号に対して位相回転補償処理を行う第1位相補償手段と、
前記第1位相補償手段によって補償された後の前記電気信号に対して分散補償処理及び位相回転補償処理をこの順で少なくとも一つの歪補償手段と、
を備える光通信システム。
9.7又は8に記載の光通信システムにおいて、
前記歪補償手段による分散補償量と前記第1分散補償手段による分散補償量の和は、前記伝送路において前記信号光が受ける分散量に等しい光通信システム。
10.7~9のいずれか一つに記載の光通信システムにおいて、
前記電気信号生成手段は、
前記第1位相補償手段により補償された後の前記信号光と局所光とを干渉させることにより4つの出力光を生成する干渉手段と、
前記4つの出力光を光電変換して4つのアナログ信号を生成する光電変換手段と、
前記4つのアナログ信号を4つのデジタル信号に変換するアナログ・デジタル変換手段と、
前記4つのデジタル信号から、前記信号光の2つの偏波成分に対応する2つの偏波信号を、前記電気信号として生成する偏波信号生成手段と、
を有する光通信システム。
11.7、8、又は10に記載の光通信システムにおいて、
前記光受信装置は、最終段の前記歪補償手段の後に設けられており、前記電気信号に対して分散補償処理を行う第2分散補償手段を備える光通信システム。
12.11に記載の光通信システムにおいて、
前記歪補償手段による分散補償量、前記第1分散補償手段による分散補償量、及び前記第2分散補償手段による分散補償量の和は、前記伝送路において前記信号光が受ける分散量に等しい光通信システム。
13.偏波多重かつ多値変調された信号光を、伝送路を介して受信するステップと、
前記信号光に基づいて電気信号を生成するステップと、
前記電気信号に対して位相回転補償処理を行うステップと、
前記第1位相補償手段によって補償された後の前記電気信号に対して分散補償処理及び位相回転補償処理をこの順で行うステップと、
を備え、
前記電気信号を生成するステップの前において、前記信号光は、前記伝送路における分散量の一部が補償されている信号処理方法。
Claims (9)
- 偏波多重かつ多値変調されていて伝送路を介して送信された信号光に基づいて電気信号を生成する電気信号生成手段と、
前記電気信号に対して位相回転補償処理を行う第1位相補償手段と、
前記第1位相補償手段によって補償された後の前記電気信号に対して分散補償処理及び位相回転補償処理をこの順で少なくとも1回行う歪補償手段と、
を備える信号処理装置。 - 請求項1に記載の信号処理装置において、
前記信号光に、光学的方法によって分散補償を行う第1分散補償手段を備え、
前記電気信号生成手段は、前記第1分散補償手段により補償された後の前記信号光に基づいて前記電気信号を生成する信号処理装置。 - 請求項1又は2に記載の信号処理装置において、
前記歪補償手段による分散補償量と前記第1分散補償手段による分散補償量の和は、前記伝送路において前記信号光が受ける分散量に等しい信号処理装置。 - 請求項1~3のいずれか一項に記載の信号処理装置において、
前記電気信号生成手段は、
前記第1位相補償手段により補償された後の前記信号光と局所光とを干渉させることにより4つの出力光を生成する干渉手段と、
前記4つの出力光を光電変換して4つのアナログ信号を生成する光電変換手段と、
前記4つのアナログ信号を4つのデジタル信号に変換するアナログ・デジタル変換手段と、
前記4つのデジタル信号から、前記信号光の2つの偏波成分に対応する2つの偏波信号を、前記電気信号として生成する偏波信号生成手段と、
を有する信号処理装置。 - 請求項1、2、又は4に記載の信号処理装置において、
最終段の前記歪補償手段の後に設けられており、前記電気信号に対して分散補償処理を行う第2分散補償手段を備える信号処理装置。 - 請求項5に記載の信号処理装置において、
前記歪補償手段による分散補償量、前記第1分散補償手段による分散補償量、及び前記第2分散補償手段による分散補償量の和は、前記伝送路において前記信号光が受ける分散量に等しい信号処理装置。 - 光信号を送信する光送信装置と、
伝送路を介して前記光信号を受信する光受信装置と、
を備え、
前記光送信装置は、
光を偏波多重かつ多値変調することにより前記光信号を生成する光信号生成手段を備え、
前記光送信装置及び前記光受信装置の一方は、前記信号光に、光学的方法によって分散補償を行う第1分散補償手段を備え、
前記光受信装置は、
前記第1分散補償手段により補償された後の前記信号光に基づいて電気信号を生成する電気信号生成手段と、
前記電気信号に対して位相回転補償処理を行う第1位相補償手段と、
前記第1位相補償手段によって補償された後の前記電気信号に対して分散補償処理及び位相回転補償処理をこの順で行う少なくとも一つの歪補償手段と、
を備える光通信システム。 - 光信号を送信する光送信装置と、
伝送路を介して前記光信号を受信する光受信装置と、
を備え、
前記光送信装置は、
前記光信号に変換される前の信号に対して分散補償処理を行う第1分散補償手段と、
前記第1分散補償手段によって補償された後の前記信号を用いて光を変調することにより前記光信号を生成する光信号生成手段と、
を備え、
前記光受信装置は、
前記信号光に基づいて電気信号を生成する電気信号生成手段と、
前記電気信号に対して位相回転補償処理を行う第1位相補償手段と、
前記第1位相補償手段によって補償された後の前記電気信号に対して分散補償処理及び位相回転補償処理をこの順で行う少なくとも一つの歪補償手段と、
を備える光通信システム。 - 偏波多重かつ多値変調された信号光を、伝送路を介して受信するステップと、
前記信号光に基づいて電気信号を生成するステップと、
前記電気信号に対して位相回転補償処理を行うステップと、
前記第1位相補償手段によって補償された後の前記電気信号に対して分散補償処理及び位相回転補償処理をこの順で行うステップと、
を備え、
前記電気信号を生成するステップの前において、前記信号光は、前記伝送路における分散量の一部が補償されている信号処理方法。
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