WO2008044595A1 - Système de transmission optique et procédé de commande de transmission optique - Google Patents
Système de transmission optique et procédé de commande de transmission optique Download PDFInfo
- Publication number
- WO2008044595A1 WO2008044595A1 PCT/JP2007/069471 JP2007069471W WO2008044595A1 WO 2008044595 A1 WO2008044595 A1 WO 2008044595A1 JP 2007069471 W JP2007069471 W JP 2007069471W WO 2008044595 A1 WO2008044595 A1 WO 2008044595A1
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- WO
- WIPO (PCT)
- Prior art keywords
- optical transmission
- optical
- signal light
- polarization
- signal
- Prior art date
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Classifications
-
- 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
- H04B10/2569—Arrangements specific to fibre transmission for the reduction or elimination of distortion or dispersion due to polarisation mode dispersion [PMD]
Definitions
- the present invention relates to an optical transmission system and an optical transmission control method, and more particularly to an optical transmission system in which a failure occurrence probability due to polarization dispersion is reduced.
- One method for devising a transmission signal modulation scheme is a method using multilevel modulation.
- the transmission bit rate can be expressed by the product of the number of codes per bit and the transmission rate.
- the number of codes per bit is generally 1, so increasing the number of codes will yield the same bit rate at a lower transmission rate.
- the factor causing BER degradation is not limited to polarization dispersion, it is necessary to extract only the amount of degradation caused by polarization dispersion from the amount of BER degradation. ,. In other words, accurate polarization dispersion equalization control cannot be performed using BER information! /. Therefore, at present, the waveform equalization method has technical difficulties.
- the amount of improvement in the polarization dispersion tolerance there is a limit to the amount of improvement in the polarization dispersion tolerance, and the amount of improvement is V that is commensurate with the cost.
- the amount of improvement is not necessarily the highest, but a method that only requires half the cost is more realistic than achieving the highest level of improvement that can be achieved with the current technology at a great cost.
- Patent Document 1 in order to reduce the influence of the polarization dispersion generated in the optical fiber, the optical signal to be transmitted is branched into two systems, and the system with the least polarization dispersion is used. A technique for selecting the signal is disclosed.
- Patent Document 1 JP-A-6-334606
- a reference signal generator is provided at the receiving end in order to select a signal of a system with less polarization dispersion, and the reference signal and the received signal of each system are selected. In comparison, the signal closer to the reference signal is selected as a signal with less polarization dispersion.
- the present invention has been made in view of the problems of the conventional techniques as described above, and its object is applicable not only to known signals but also to unknown signals.
- An optical transmission system includes means for branching an optical transmission output into a plurality of parts, different optical transmission paths that transmit these branched signal lights, and polarization dispersion states of signal lights that have passed through these optical transmission paths. And a control means for selectively controlling the signal light that has passed through the optical transmission path based on the quality degradation due to polarization dispersion, which is the monitoring result.
- An optical transmission control method includes a step of branching an optical transmission output into a plurality of parts and transmitting the branched signal light through different optical transmission lines, and polarizations of the signal lights passing through these optical transmission lines.
- a monitoring step for monitoring each of the dispersion states; and a control step for selectively controlling the signal light that has passed through the optical transmission path based on quality degradation due to polarization dispersion, which is the monitoring result.
- the first effect of the present invention is to have high reliability. The reason is that even if signal quality deteriorates in one transmission channel by selecting a high-quality transmission channel from multiple optical transmission channels, even if the signal quality deteriorates in one transmission channel, switch to another transmission channel. This is because the transmission / reception error occurrence probability can be reduced by transmitting and receiving data.
- a second effect of the present invention is high availability. The reason is that it is not necessary to stop the service because it is possible to switch without interruption even when the transmission channel is switched by buffering at the receiver.
- a third effect of the present invention is that the introduction cost can be reduced. The reason is that it is not necessary to prepare an optical signal source for each optical transmission channel because an optical signal source can be shared even if a plurality of optical transmission channels are used. Another reason is that existing laying transmission channels and optical transceivers can be used.
- the fourth effect of the present invention is that the operation cost can be lowered. The reason is that it is possible to distinguish between system failure and transmission / reception error due to polarization dispersion, which is a temporary failure due to environmental changes, and it is possible to reduce the effort of investigating and repairing the cause when a failure occurs.
- a fifth effect of the present invention is simple control. The reason is that the polarization dispersion resistance can be increased only by transmission channel switching control without using complicated waveform equalization technology and signal compensation technology.
- the sixth effect of the present invention is that the system construction is simple. The reason is that existing installed transmission channels and optical transmission / reception devices can be used, so it is possible to use a system that has already been designed without the need to newly install a transmission channel or optical transmission / reception device for the present invention. This is because a new system design is required!
- the seventh effect of the present invention is that it can sufficiently handle not only known signals but also unknown signals.
- the reason for this is that when selecting a system signal that is less affected by polarization dispersion, a device that monitors the degree of polarization is used without comparison with the reference signal.
- FIG. 1 is a system block diagram according to an embodiment of the present invention.
- FIG. 2 is a system block diagram of one embodiment of the present invention.
- FIG. 3 is a system block diagram of another embodiment of the present invention.
- FIG. 1 is a schematic functional block diagram of an embodiment of the present invention.
- the optical signal output from the transmitter 1 is branched by the branching device 2.
- the branched optical signal is guided to optical transmission channels 3 and 4, respectively.
- Each of these optical signals is input to the switch 7 via the reception buffers 5 and 6, respectively.
- the switching timing is determined from the polarization dispersion monitoring result by the polarization dispersion monitoring device 9.
- the optical signal output from the transmitter 1 is branched by the branching unit 2, and the branched optical signal is guided to the optical transmission channels 3 and 4, respectively.
- the two branched signals are equivalent except that the transmission channels are different, and after passing through the receiving buffers 5 and 6, respectively, only one of the optical signals after transmission is selected by switch 7. Is done.
- the switch control circuit 10 does not control which one is selected. Is done.
- the signal selected by the switch 7 is guided to the receiver 8.
- signal transmission is performed between the transmitter 1 and the receiver 8.
- the switching timing is determined from the monitoring result by the polarization dispersion monitoring device 9.
- a part of the optical signal is taken out from the transmission channels 3 and 4 by branching and input to the polarization dispersion monitoring device 9, so that the polarization state of the transmission channel is monitored in real time.
- the switch control circuit 10 can know which of the transmission channels 3 and 4 is a transmission channel with a small polarization dispersion from the polarization dispersion monitoring result.
- the transmission error occurrence probability is reduced to 1 / square.
- Instantaneous signal interruption occurs at the moment of transmission channel switching by switch 7, but by storing a certain amount of transmission information in reception buffers 5 and 6, signal interruption at switch switching is prevented. be able to.
- FIG. Fig. 2 shows the case where the polarization degree monitoring device 32 is used as the polarization dispersion monitoring device 9 in Fig. 1 and FIFO (First-In First-Out) type electric buffers 28, 29 are used as the buffer of the receiving unit.
- FIFO First-In First-Out
- the transmission electrical signal generated from the signal source 21 is converted into an electro-optical converter (E / O converter).
- the optical light is converted at 22, and a 1: 2 splitter 23 is used as a branching device, and optical transmission is performed through two spatially multiplexed optical transmission channels 24 and 25.
- optical signals after transmission are photoelectrically converted by photoelectric converters (O / E converters) 26 and 27, respectively, and input to FIFO type electrical buffers 28 and 29.
- photoelectric converters O / E converters
- the noters 28 and 29 can always store signals transmitted during the switching time of the electric switch 30 having two inputs and one output. Noffa 28,
- the transmission signal that has passed through 29 is input to the electrical switch 30.
- the electrical switch 30 selects one of the output force of the O / E converter 26 and the output of the O / E converter 27 and guides it to the receiver 31. .
- a part of the transmitted optical signal is input to the polarization degree monitoring device 32 from the two optical transmission channels 24 and 25.
- Polarization degree meters 321 and 322 are provided inside the polarization degree monitoring device 32.
- the polarization degree monitor result is sent to the switch control circuit 33 via the external interface circuit 323.
- a CPU 331 and a memory 332 are provided inside the switch control circuit 33.
- a polarization degree threshold value for switching the switch 30 is set in advance.
- the CPU 331 determines the switching timing of the switch 30 by using the switching threshold value and the polarization degree monitoring result, and instructs the switching.
- the transmission electrical signal generated from the signal source 21 is converted into electrical light by the E / O converter 22, and the optical signal is split into two by the 1-input 2-output splitter 23.
- the branched optical signal is guided to two optical transmission channels 24 and 25 for optical transmission.
- the two branched signals are equivalent transmission optical signals except that the transmission channels are different.
- the optical signal after transmission is photoelectrically converted by the O / E converters 26 and 27, guided to the buffers 28 and 29, and input to the electrical switch 30.
- the electrical switch 30 selects one of the output of the buffer 28 and the output of the buffer 29 and inputs it to the receiver 31. As a result, signal reception is performed.
- the noters 28 and 29 can always buffer the amount of signal transmitted during at least the switching time of the electric switch 30.
- the switch control circuit 33 records a switch switching start time tl and an end time t2. When switching from the optical transmission channel 24 to the optical transmission channel 25, only the output data of the buffer 28 is validated by the switch control circuit 33, and the output data of the buffer 29 is invalidated.
- a part of the transmitted optical signal is input to the polarization degree monitoring device 32 from the two optical transmission channels 24 and 25.
- Polarization degree meters 321 and 322 are provided inside the polarization degree monitoring device 32, and the polarization degrees of the optical transmission channels 24 and 25 are measured, respectively. These measurement results are sent to the switch control circuit 33 via the external interface circuit 323.
- a CPU 331, a memory 332, and a force S are provided inside the switch control circuit 33.
- a polarization degree threshold value for switching the switch 30 is set in advance.
- the CPU 331 compares the switching threshold value with the polarization degree monitoring result input from the polarization degree monitoring device 32, and when one of the polarization degree monitoring results exceeds the threshold value, it switches to the other or without switching.
- the switch 30 is now instructed to keep the status quo.
- the polarization dispersion instantaneously increases or decreases and returns to the original amount again. If the ambient temperature changes, it will increase or decrease over time. Furthermore, due to wavelength dependence, even if the same environmental change occurs, the amount of signal degradation due to polarization dispersion varies depending on the transmitted optical signal wavelength. Therefore, when the degree of polarization of the optical transmission channel 24 exceeds the threshold value, the degree of polarization of the optical transmission channel 25 may simultaneously exceed the threshold value.
- the probability of occurrence of the polarization dispersion amount of the two optical transmission channels simultaneously exceeding the threshold value is low, so two optical transmission channels should be used. Therefore, due to a synergistic effect, the probability of transmission failure is 1 / square compared to the case of one channel, and the probability of transmission failure can be reduced.
- the switch control circuit 33 is provided with a switching protection timer. This timer may be provided in the CPU 331. With this timer, the switch 30 is instructed to switch when the time exceeding the switching threshold continues for a certain time. This prevents the switching switch 30 from switching violently (chattering) in a short time. Switching the transmission channel with the switch 30 is when the polarization dispersion continuously exceeds a certain threshold. It is assumed that the switching threshold value determined in the switch control circuit 33 is determined so as to be a stricter condition than the occurrence of a signal deterioration failure (SF) in the receiver 31.
- SF signal deterioration failure
- Signal degradation due to polarization dispersion is one of the causes of SF, but there are various factors such as OSNR (Optical Signal Noise Ratio) degradation.
- OSNR Optical Signal Noise Ratio
- degradation factors other than polarization dispersion once degradation occurs, it continues to occur, whereas in the case of polarization dispersion, it may recover instantaneously. This is because degradation due to other than polarization dispersion is due to a failure or connection error in the transmission device, whereas degradation due to polarization dispersion is due to a change in the state of the transmission channel. It's not a malfunction!
- the switching threshold defined in the switch control circuit 33 By setting the switching threshold defined in the switch control circuit 33 to be stricter than the SF condition, deterioration due to polarization dispersion is eliminated when SF occurs. It is possible to determine whether it is caused by a change in the transmission channel state caused by dispersion, and can be used as a judgment material for the necessity of repairing the equipment.
- the receiver 31 can perform signal transmission / reception with reduced influence of polarization dispersion. There is a monotonically increasing correlation between polarization degree and polarization dispersion, and there is also a one-to-one correlation between polarization degree and code error rate. A transmission system that can reduce the probability of code error rate reduction can be realized.
- the number of branches can be determined to an arbitrary number of two or more.
- the polarization dispersion monitoring method may be the force described with reference to a method using a polarization degree meter, or another method.
- FIG. 3 is a functional block diagram of another embodiment of the present invention, which is an example of using wavelength-multiplexed optical signals as different optical transmission channels in an optical transmission system.
- the same parts as those in Fig. 2 are indicated by the same reference numerals.
- CW (Continus Wave) light output from semiconductor lasers 41 and 42 having different oscillation wavelengths is input to optical modulators 42 and 43, respectively.
- the oscillation wavelength of the semiconductor laser 41 is the wavelength ⁇ 1
- the oscillation wavelength of the semiconductor laser 42 is the wavelength ⁇ 2.
- the optical modulators 42 and 43 modulate the optical intensity of the CW input by the electric modulation signal from the signal source 45. Outputs of these optical modulators 42 and 43 are wavelength-multiplexed by a multiplexer 46 and then transmitted by an optical transmission channel 47.
- the signal transmitted through the optical transmission channel 47 is separated into optical signals for each wavelength by the wavelength separator 48, the optical signal of wavelength ⁇ 1 is the optical transmission channel 49, and the optical signal of wavelength ⁇ 2 is Each is routed to an optical transmission channel 50.
- the optical signal after transmission is photoelectrically converted by opto-electric converters (O / E converters) 51 and 52, received by the optical receivers 53 and 54, respectively, and then input to the FIFO buffers 55 and 56.
- Electric 2 1 Input to switch 57.
- the electric switch 57 selects either the output force of the buffer 55 or the output of the buffer 56.
- the polarization degree monitoring device 32 inputs a part of the transmission optical signal from the two optical transmission channels 49 and 50.
- Polarization degree meters 321 and 322 are provided inside the polarization degree monitoring device 32.
- Polarization degree monitor result to switch control circuit 33 via external interface circuit 323 Is sent out.
- a CPU 331, a memory 332, and a force S are provided inside the switch control circuit 33.
- a polarization degree threshold value for switching the switch 57 is set in advance.
- the CPU 331 determines the switching timing of the switch 57 from the switching threshold value and the polarization degree monitor result, and instructs switching.
- optical signals having the wavelengths ⁇ 1 and ⁇ 2 transmitted through the optical transmission channels 49 and 50 are separate optical signals having the same force S and different wavelengths as the data. Since polarization dispersion is wavelength dependent, the amount of polarization dispersion varies with the wavelength. Therefore, these wavelengths should be selected so that the wavelength difference is as large as possible.
- the semiconductor laser 41 and the optical modulator 42 are regarded as the optical transmitter 100 with the wavelength ⁇ 1
- the semiconductor laser 43 and the optical modulator 44 are the optical transmitter 200 with the wavelength 2.
- the ⁇ / ⁇ converter 51 and the receiver 53 are regarded as an optical receiver 300 having a wavelength ⁇ 1
- the ⁇ / ⁇ converter 52 and the receiver 54 are optical signals with a wavelength of 2.
- receiver 400 is regarded as receiver 400
- an unused wavelength channel is polarization-dispersed by adding an optical transmission channel selector 1000 comprising a FIFO buffer 55, 56, a switch 57, and a switch control circuit 33. Effective use as an optical transmission channel for improving resistance.
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Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
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JP2008538688A JP5093111B2 (ja) | 2006-10-11 | 2007-10-04 | 光伝送システム及び光伝送制御方法 |
US12/442,559 US8175455B2 (en) | 2006-10-11 | 2007-10-04 | Optical transmission system and optical transmission control method |
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JP2006-277053 | 2006-10-11 | ||
JP2006277053 | 2006-10-11 |
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WO2008044595A1 true WO2008044595A1 (fr) | 2008-04-17 |
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PCT/JP2007/069471 WO2008044595A1 (fr) | 2006-10-11 | 2007-10-04 | Système de transmission optique et procédé de commande de transmission optique |
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US (1) | US8175455B2 (ja) |
JP (1) | JP5093111B2 (ja) |
CN (1) | CN101523772A (ja) |
WO (1) | WO2008044595A1 (ja) |
Cited By (1)
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CN102035598A (zh) * | 2009-09-28 | 2011-04-27 | 冲电气工业株式会社 | 光信号质量监控装置 |
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EP2436128B1 (en) | 2010-02-20 | 2020-04-08 | Huawei Technologies Co., Ltd. | Clock phase recovery apparatus |
CN103297016B (zh) * | 2012-03-01 | 2020-06-19 | 朗美通技术英国有限公司 | 光发射器和光通信方法 |
JP5994294B2 (ja) * | 2012-03-06 | 2016-09-21 | 富士通株式会社 | 光伝送装置および光伝送方法 |
US9490895B2 (en) * | 2013-09-20 | 2016-11-08 | Finisar Corporation | Ultrafast high resolution optical channel monitor |
CN108306690A (zh) * | 2018-01-11 | 2018-07-20 | 青岛海信宽带多媒体技术有限公司 | 光模块与通道切换方法 |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2001505668A (ja) * | 1996-07-23 | 2001-04-24 | コラム テクノロジーズ インコーポレイテッド | 誤り耐性の高い光学的ルート切換えスイッチ |
JP2005348322A (ja) * | 2004-06-07 | 2005-12-15 | Osaka Univ | 偏波モード分散モニタリング方式、偏波モード分散補償方式、光ファイバ通信方式、及び光ファイバ通信システム |
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Publication number | Priority date | Publication date | Assignee | Title |
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JPH0821895B2 (ja) | 1993-05-21 | 1996-03-04 | 日本電気株式会社 | 人工衛星内部光信号伝送路 |
JPH08125636A (ja) | 1994-10-20 | 1996-05-17 | Hitachi Ltd | 波長多重プロテクション方法および伝送装置 |
WO1999028723A1 (fr) * | 1997-11-28 | 1999-06-10 | Fujitsu Limited | Procede de mesure de la dispersion en mode de polarisation, dispositif de commande de compensation de dispersion et procede de commande de compensation de dispersion |
JP2001203637A (ja) * | 2000-01-19 | 2001-07-27 | Mitsubishi Electric Corp | 波長多重光伝送システム |
KR100487201B1 (ko) | 2003-02-04 | 2005-05-04 | 삼성전자주식회사 | 전기 버퍼를 이용한 대용량 광 라우터 |
WO2004077701A1 (ja) * | 2003-02-25 | 2004-09-10 | Fujitsu Limited | 光伝送における現用及び予備回線の切替方法及び装置 |
JP3851619B2 (ja) | 2003-07-24 | 2006-11-29 | アンリツ株式会社 | 中継システム |
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- 2007-10-04 US US12/442,559 patent/US8175455B2/en active Active
- 2007-10-04 CN CNA2007800382752A patent/CN101523772A/zh active Pending
- 2007-10-04 JP JP2008538688A patent/JP5093111B2/ja active Active
- 2007-10-04 WO PCT/JP2007/069471 patent/WO2008044595A1/ja active Application Filing
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2001505668A (ja) * | 1996-07-23 | 2001-04-24 | コラム テクノロジーズ インコーポレイテッド | 誤り耐性の高い光学的ルート切換えスイッチ |
JP2005348322A (ja) * | 2004-06-07 | 2005-12-15 | Osaka Univ | 偏波モード分散モニタリング方式、偏波モード分散補償方式、光ファイバ通信方式、及び光ファイバ通信システム |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN102035598A (zh) * | 2009-09-28 | 2011-04-27 | 冲电气工业株式会社 | 光信号质量监控装置 |
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Publication number | Publication date |
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CN101523772A (zh) | 2009-09-02 |
JP5093111B2 (ja) | 2012-12-05 |
JPWO2008044595A1 (ja) | 2010-02-12 |
US8175455B2 (en) | 2012-05-08 |
US20100021169A1 (en) | 2010-01-28 |
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