CA2311023A1 - A method of transmitting data via an optical wdm transmission system and a wdm transmission system - Google Patents
A method of transmitting data via an optical wdm transmission system and a wdm transmission system Download PDFInfo
- Publication number
- CA2311023A1 CA2311023A1 CA002311023A CA2311023A CA2311023A1 CA 2311023 A1 CA2311023 A1 CA 2311023A1 CA 002311023 A CA002311023 A CA 002311023A CA 2311023 A CA2311023 A CA 2311023A CA 2311023 A1 CA2311023 A1 CA 2311023A1
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- data
- channels
- wavelength
- transmission system
- transmission
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- 230000005540 biological transmission Effects 0.000 title claims abstract description 37
- 238000000034 method Methods 0.000 title claims abstract description 22
- 230000003287 optical effect Effects 0.000 title claims abstract description 10
- 238000006243 chemical reaction Methods 0.000 claims description 2
- 230000011664 signaling Effects 0.000 claims 1
- 239000006185 dispersion Substances 0.000 description 9
- 239000003365 glass fiber Substances 0.000 description 7
- 230000000694 effects Effects 0.000 description 5
- 230000005693 optoelectronics Effects 0.000 description 3
- 230000006978 adaptation Effects 0.000 description 1
- 239000000969 carrier Substances 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 230000008878 coupling Effects 0.000 description 1
- 238000010168 coupling process Methods 0.000 description 1
- 238000005859 coupling reaction Methods 0.000 description 1
- 239000000835 fiber Substances 0.000 description 1
- 238000003780 insertion Methods 0.000 description 1
- 230000037431 insertion Effects 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04J—MULTIPLEX COMMUNICATION
- H04J14/00—Optical multiplex systems
- H04J14/02—Wavelength-division multiplex systems
- H04J14/0287—Protection in WDM systems
- H04J14/0293—Optical channel protection
- H04J14/0294—Dedicated protection at the optical channel (1+1)
-
- 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
- H04B10/03—Arrangements for fault recovery
- H04B10/032—Arrangements for fault recovery using working and protection systems
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04J—MULTIPLEX COMMUNICATION
- H04J14/00—Optical multiplex systems
- H04J14/02—Wavelength-division multiplex systems
- H04J14/0227—Operation, administration, maintenance or provisioning [OAMP] of WDM networks, e.g. media access, routing or wavelength allocation
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04J—MULTIPLEX COMMUNICATION
- H04J14/00—Optical multiplex systems
- H04J14/02—Wavelength-division multiplex systems
- H04J14/0227—Operation, administration, maintenance or provisioning [OAMP] of WDM networks, e.g. media access, routing or wavelength allocation
- H04J14/0241—Wavelength allocation for communications one-to-one, e.g. unicasting wavelengths
- H04J14/0242—Wavelength allocation for communications one-to-one, e.g. unicasting wavelengths in WDM-PON
- H04J14/0245—Wavelength allocation for communications one-to-one, e.g. unicasting wavelengths in WDM-PON for downstream transmission, e.g. optical line terminal [OLT] to ONU
- H04J14/0246—Wavelength allocation for communications one-to-one, e.g. unicasting wavelengths in WDM-PON for downstream transmission, e.g. optical line terminal [OLT] to ONU using one wavelength per ONU
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L1/00—Arrangements for detecting or preventing errors in the information received
- H04L1/004—Arrangements for detecting or preventing errors in the information received by using forward error control
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04J—MULTIPLEX COMMUNICATION
- H04J14/00—Optical multiplex systems
- H04J14/02—Wavelength-division multiplex systems
- H04J14/0278—WDM optical network architectures
- H04J14/0279—WDM point-to-point architectures
Landscapes
- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Optical Communication System (AREA)
- Detection And Prevention Of Errors In Transmission (AREA)
Abstract
A method of transmitting data via an optical WDM
transmission system is proposed wherein data channels are multiplexed for the transmission and demultiplexed again following the transmission and the data of the individual data channel 1 are distributed among at least 2 wavelength channels 14. Additionally, redundant information can be added to the data of the individual data channels.
transmission system is proposed wherein data channels are multiplexed for the transmission and demultiplexed again following the transmission and the data of the individual data channel 1 are distributed among at least 2 wavelength channels 14. Additionally, redundant information can be added to the data of the individual data channels.
Description
A Method of Transmitting Data via an Optical WDM
Transmission System and a WDM Transmission System The invention is based on a method of transmitting data via an optical WDM transmission system and a WDM transmission system according to the preamble of the independent claims.
Light of different wavelengths is used for the transmission of data via a glass fibre link. In order to be able to better utilize the large bandwidth of a glass fibre transmission link, wavelength division multiplex (WDM) methods are conventionally used. Here a number of, modulated optical carriers with different wavelengths are transmitted simultaneously in a glass fibre. At the transmitting end a separate transmitting laser is provided for each channel and the optical signals of all the lasers are input-coupled into a glass fibre with the aid of a coupling arrangement. In the glass fibre the signals pass to the receiver where the channels are separated again by a corresponding frequency-selective arrangement and are fed to opto-electronic receivers. In previously known systems and methods the data of individual channels are in each case fed to a laser. The modulation of the laser then takes place in accordance with the data stream. A data channel is thus permanently assigned to a specific wavelength. If a second data channel is added, it is connected to a laser of a second wavelength. The wavelength channels of the two lasers are multiplexed via a multiplexer and input-coupled into a glass fibre. As the two data channels are transmitted by conversion into wavelength channels of different wavelengths, the different wavelengths are also subject to different dispersion effects. In addition to the chromatic dispersion of the fibre, the polarisation mode dispersion is also of ' CA 02311023 2000-06-08 significance at high bit rates. This originates from the different propagation speeds of the two modes of a wavelength channel polarised orthogonally to one another.
The polarisation mode dispersion also affects the signals of different wavelengths in different ways and influences the quality of the transmission in individual wavelength channels due to its time fluctuations.
Therefore the object of the invention is to propose a WDM
transmission method and TniDM system in which the individual data channels are less likely to be disturbed.
The method according to the invention of transmitting data via an optical wDM transmission system here has the advantage that the data of the individual data channel are converted to at least two wavelength channels of different wavelengths. In this way, when a wavelength channel is greatly disturbed due to polarisation mode dispersion effects, data are still transmitted. Due to the additional use of redundancy-increasing procedures, such as for example FEC, the entire transmitted information can then be recovered again from the transmitted data. The system is thus more resistant to dispersion disturbances on the glass fibre transmission link.
The method is particularly advantageous if the data of each data channel are distributed among every possible wavelength of the wavelength multiplex. As a result of the widest possible distribution of the data of each channel among each possible wavelength in the wavelength division multiplex, the robustness of the transmission is substantially increased. The influences of the dispersion effects in one single wavelength channel no longer affect the quality of the transmitted data of a data channel to such an extent.
Transmission System and a WDM Transmission System The invention is based on a method of transmitting data via an optical WDM transmission system and a WDM transmission system according to the preamble of the independent claims.
Light of different wavelengths is used for the transmission of data via a glass fibre link. In order to be able to better utilize the large bandwidth of a glass fibre transmission link, wavelength division multiplex (WDM) methods are conventionally used. Here a number of, modulated optical carriers with different wavelengths are transmitted simultaneously in a glass fibre. At the transmitting end a separate transmitting laser is provided for each channel and the optical signals of all the lasers are input-coupled into a glass fibre with the aid of a coupling arrangement. In the glass fibre the signals pass to the receiver where the channels are separated again by a corresponding frequency-selective arrangement and are fed to opto-electronic receivers. In previously known systems and methods the data of individual channels are in each case fed to a laser. The modulation of the laser then takes place in accordance with the data stream. A data channel is thus permanently assigned to a specific wavelength. If a second data channel is added, it is connected to a laser of a second wavelength. The wavelength channels of the two lasers are multiplexed via a multiplexer and input-coupled into a glass fibre. As the two data channels are transmitted by conversion into wavelength channels of different wavelengths, the different wavelengths are also subject to different dispersion effects. In addition to the chromatic dispersion of the fibre, the polarisation mode dispersion is also of ' CA 02311023 2000-06-08 significance at high bit rates. This originates from the different propagation speeds of the two modes of a wavelength channel polarised orthogonally to one another.
The polarisation mode dispersion also affects the signals of different wavelengths in different ways and influences the quality of the transmission in individual wavelength channels due to its time fluctuations.
Therefore the object of the invention is to propose a WDM
transmission method and TniDM system in which the individual data channels are less likely to be disturbed.
The method according to the invention of transmitting data via an optical wDM transmission system here has the advantage that the data of the individual data channel are converted to at least two wavelength channels of different wavelengths. In this way, when a wavelength channel is greatly disturbed due to polarisation mode dispersion effects, data are still transmitted. Due to the additional use of redundancy-increasing procedures, such as for example FEC, the entire transmitted information can then be recovered again from the transmitted data. The system is thus more resistant to dispersion disturbances on the glass fibre transmission link.
The method is particularly advantageous if the data of each data channel are distributed among every possible wavelength of the wavelength multiplex. As a result of the widest possible distribution of the data of each channel among each possible wavelength in the wavelength division multiplex, the robustness of the transmission is substantially increased. The influences of the dispersion effects in one single wavelength channel no longer affect the quality of the transmitted data of a data channel to such an extent.
Advantageously, to improve the method, redundant information items are included in the data stream, these substantially improving the transmitted data quality in the form of a FEC (forward error correction) procedure.
The WDM transmission system according to the invention comprises at the transmitting end a means for distributing the data of the different data channels among wavelength channels and at the receiving end a means for redistributing these data.
An exemplary embodiment of the invention is illustrated in the drawing and explained in detail in the following description.
In the drawing:
Figure 1 schematically illustrates the construction of a WDM transmission system with an increase in redundancy, and Figure 2 illustrates an example of the distribution of the data according to the method according to the invention.
Figure 1 schematically illustrates a WDM transmission system. A transmitter 12 is connected to a receiver 13 via a transmission link 6. Data channels 1, here referenced Ch1 to Chn, are connected to the transmitter 12. The data channels 1 are directly connected to a means 2 for inserting redundant information. A means 3 for distributing wavelengths is directly connected thereto.
The outputs of these two means 2 and 3, which in this exemplary embodiment have been represented as one unit, are each connected to the input ends of lasers 4. The lasers 4 are connected to a multiplexer 5 via wavelength channels ' CA 02311023 2000-06-08 14. The multiplexer 5 generates a wavelength division multiplex 7 which is connected to the input of a receiving-end demultiplexer 8 via a transmission link 6. The wavelength channels 14 connected to the demultiplexer 8 are each connected to opto-electronic receivers 9. The output of the opto-electronic receivers 9 is connected to a means for restoring the data channels and a means 11 for reconstructing the original data signal from the redundant transmitted signal. The originally fed-in data channels 1 10 are present again at the output of the means l0 and 11, which in this exemplary embodiment have been shown in combined form.
In the form of an example, Figure 2 illustrates how the data of the data channels are distributed among wavelength channels. A data channel Ch1 is schematically illustrated in the upper part of Figure 2. This data channel Ch1 contains information units 1 to 6 for a time unit of time 1 to time 6. These information units 1 to 6 are converted into information units A1 to A8 in the means 3 for adding redundant information. Here the originally present nbits are converted into a number of mbits, where m > n. This procedure takes place in parallel for all incoming data channels, thus also for the data channel Chn whose information units 1 to 6 are converted into redundant information units X1 to X8. The lower part of Figure 2 illustrates the scheme in which the redundant data A1 to A8 and X1 to X8 are distributed among the wavelength channels.
It can be seen that at a time 1 all the information items of a data channel, namely A1 to A8, are transmitted distributed among eight different wavelength channels. The transmission of the respective first information unit of each data channel A1 to X1 takes place within a wavelength channel. The advantage of the proposed procedure is 35~obvious. Even in the simplest case,.in which the information of the channels is distributed without redundant information among different wavelength channels, in the event of the loss of data on the transmission link due to dispersion effects, no total loss of a channel is observable. The insertion of redundant information reduces 5 the risk of loss of information due to data loss. However the transmission bandwidth is also reduced. One possible procedure is that of forward error correction, which is already used in optical 10 kb/s transmission systems, see OFC'99, Post Deadline Paper, N Bergano et al. "640 Gbit/s Transmission of 64 WDM Channels..".
The described example of distributing the data channels in wavelength channels can be modified. It is possible to determine the influence of polarisation mode dispersion in a wavelength channel and in the event of severe disturbances to remove this channel from the multiplex. A
dynamic adaptation of the wavelength division multiplex to the factors currently prevailing on the transmission link is possible by measurement of the PMD effect per wavelength channel.
Additionally, the bit rates of the wavelength channels of the transmitter 12 Txi (i = l..m) need not correspond to the bit rates of the original data channels Chj (j - l..n). It is merely necessary for the overall information volume of the transmitted data provided with redundancy ((n x bit rate Ch) + redundancy) to correspond to, or be smaller than, the information volume of the wavelength division multiplex (m x bit rate Tx).
The WDM transmission system according to the invention comprises at the transmitting end a means for distributing the data of the different data channels among wavelength channels and at the receiving end a means for redistributing these data.
An exemplary embodiment of the invention is illustrated in the drawing and explained in detail in the following description.
In the drawing:
Figure 1 schematically illustrates the construction of a WDM transmission system with an increase in redundancy, and Figure 2 illustrates an example of the distribution of the data according to the method according to the invention.
Figure 1 schematically illustrates a WDM transmission system. A transmitter 12 is connected to a receiver 13 via a transmission link 6. Data channels 1, here referenced Ch1 to Chn, are connected to the transmitter 12. The data channels 1 are directly connected to a means 2 for inserting redundant information. A means 3 for distributing wavelengths is directly connected thereto.
The outputs of these two means 2 and 3, which in this exemplary embodiment have been represented as one unit, are each connected to the input ends of lasers 4. The lasers 4 are connected to a multiplexer 5 via wavelength channels ' CA 02311023 2000-06-08 14. The multiplexer 5 generates a wavelength division multiplex 7 which is connected to the input of a receiving-end demultiplexer 8 via a transmission link 6. The wavelength channels 14 connected to the demultiplexer 8 are each connected to opto-electronic receivers 9. The output of the opto-electronic receivers 9 is connected to a means for restoring the data channels and a means 11 for reconstructing the original data signal from the redundant transmitted signal. The originally fed-in data channels 1 10 are present again at the output of the means l0 and 11, which in this exemplary embodiment have been shown in combined form.
In the form of an example, Figure 2 illustrates how the data of the data channels are distributed among wavelength channels. A data channel Ch1 is schematically illustrated in the upper part of Figure 2. This data channel Ch1 contains information units 1 to 6 for a time unit of time 1 to time 6. These information units 1 to 6 are converted into information units A1 to A8 in the means 3 for adding redundant information. Here the originally present nbits are converted into a number of mbits, where m > n. This procedure takes place in parallel for all incoming data channels, thus also for the data channel Chn whose information units 1 to 6 are converted into redundant information units X1 to X8. The lower part of Figure 2 illustrates the scheme in which the redundant data A1 to A8 and X1 to X8 are distributed among the wavelength channels.
It can be seen that at a time 1 all the information items of a data channel, namely A1 to A8, are transmitted distributed among eight different wavelength channels. The transmission of the respective first information unit of each data channel A1 to X1 takes place within a wavelength channel. The advantage of the proposed procedure is 35~obvious. Even in the simplest case,.in which the information of the channels is distributed without redundant information among different wavelength channels, in the event of the loss of data on the transmission link due to dispersion effects, no total loss of a channel is observable. The insertion of redundant information reduces 5 the risk of loss of information due to data loss. However the transmission bandwidth is also reduced. One possible procedure is that of forward error correction, which is already used in optical 10 kb/s transmission systems, see OFC'99, Post Deadline Paper, N Bergano et al. "640 Gbit/s Transmission of 64 WDM Channels..".
The described example of distributing the data channels in wavelength channels can be modified. It is possible to determine the influence of polarisation mode dispersion in a wavelength channel and in the event of severe disturbances to remove this channel from the multiplex. A
dynamic adaptation of the wavelength division multiplex to the factors currently prevailing on the transmission link is possible by measurement of the PMD effect per wavelength channel.
Additionally, the bit rates of the wavelength channels of the transmitter 12 Txi (i = l..m) need not correspond to the bit rates of the original data channels Chj (j - l..n). It is merely necessary for the overall information volume of the transmitted data provided with redundancy ((n x bit rate Ch) + redundancy) to correspond to, or be smaller than, the information volume of the wavelength division multiplex (m x bit rate Tx).
Claims (7)
1. A method of transmitting data via an optical WDM
(wavelength division multiplex) transmission system, wherein the data channels (1) are multiplexed for the transmission and demultiplexed again following the transmission, characterised in that the data of the individual data channel (1) are distributed between at least two wavelength channels (14).
(wavelength division multiplex) transmission system, wherein the data channels (1) are multiplexed for the transmission and demultiplexed again following the transmission, characterised in that the data of the individual data channel (1) are distributed between at least two wavelength channels (14).
2. A method of transmitting data via an optical WDM
(wavelength division multiplex) transmission system, wherein the data channels (1) are multiplexed for the transmission and demultiplexed following the transmission, characterised in that the data of every data channel (1) are distributed among every possible wavelength of the wavelength multiplex (7).
(wavelength division multiplex) transmission system, wherein the data channels (1) are multiplexed for the transmission and demultiplexed following the transmission, characterised in that the data of every data channel (1) are distributed among every possible wavelength of the wavelength multiplex (7).
3. A method according to Claim 1 or Claim 2, characterised in that the data of the data channels (1) are supplemented by redundant information before their conversion to the wavelength channels (14).
4. A method according to Claim 3, characterised in that redundant information is inserted in a form suitable for the forward error correction procedure.
5. A method according to Claim 1 or 2, characterised in that wavelength channels of poor quality are identified in the receiver and following signalling in the receiver wavelength channels are excluded from and included in the multiplex.
6. A WDM transmission system comprising at least one
7 transmitter (12), a transmission link (6) and at least one receiver (13), wherein data channels (1) incoming at the transmitter end are converted to wavelength channels (14) and fed to at least one multiplexer (3), and wherein at the receiver end a demultiplexer (8) separates the wavelength multiplex (7) into data channels (1) again, characterised in that at the transmitter end a means (2) is provided for distributing the different data channels among different wavelength channels and at the receiving end a means (10) is provided for redistributing the data of the wavelength channels (14) among data channels (1).
7. A WDM transmission system comprising at least one transmitter (12), a transmission link (6) and at least one receiver (13), wherein data channels (1) incoming at the transmitter end are converted to wavelength channels (14) and fed to at least one multiplexer (3), and wherein at the receiver end a demultiplexer (8) separates the wavelength multiplex (7) into data channels (1) again, characterised in that at the transmitter end a means (3) is provided for inserting redundant information and a means (2) is provided for distributing the data of the different data channels (1) among wavelength channels (14), and at the receiver end a means (10) is provided for redistributing the data among data channels and a means (11) is provided for reconstructing the data channels.
7. A WDM transmission system comprising at least one transmitter (12), a transmission link (6) and at least one receiver (13), wherein data channels (1) incoming at the transmitter end are converted to wavelength channels (14) and fed to at least one multiplexer (3), and wherein at the receiver end a demultiplexer (8) separates the wavelength multiplex (7) into data channels (1) again, characterised in that at the transmitter end a means (3) is provided for inserting redundant information and a means (2) is provided for distributing the data of the different data channels (1) among wavelength channels (14), and at the receiver end a means (10) is provided for redistributing the data among data channels and a means (11) is provided for reconstructing the data channels.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19927451.7 | 1999-06-16 | ||
| DE19927451A DE19927451A1 (en) | 1999-06-16 | 1999-06-16 | Method for the transmission of data via an optical WDM transmission system, and WDM transmission system |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2311023A1 true CA2311023A1 (en) | 2000-12-16 |
Family
ID=7911423
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002311023A Abandoned CA2311023A1 (en) | 1999-06-16 | 2000-06-08 | A method of transmitting data via an optical wdm transmission system and a wdm transmission system |
Country Status (4)
| Country | Link |
|---|---|
| EP (1) | EP1061685A2 (en) |
| JP (1) | JP2001024584A (en) |
| CA (1) | CA2311023A1 (en) |
| DE (1) | DE19927451A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2021190031A1 (en) * | 2020-03-25 | 2021-09-30 | 京信网络***股份有限公司 | Wdm-based data transmission method, apparatus, and system, and storage medium |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7272319B1 (en) * | 1999-03-04 | 2007-09-18 | Lucent Technologies Inc. | System and method for secure multiple wavelength communication on optical fibers |
| DE10320814A1 (en) * | 2003-05-08 | 2004-12-09 | Deutsches Zentrum für Luft- und Raumfahrt e.V. | Process for the optical transmission of digital signals |
| US11476978B2 (en) | 2017-09-18 | 2022-10-18 | Osram Gmbh | Method for linear encoding of signals for the redundant transmission of data via multiple optical channels |
-
1999
- 1999-06-16 DE DE19927451A patent/DE19927451A1/en not_active Withdrawn
-
2000
- 2000-05-19 EP EP00440148A patent/EP1061685A2/en not_active Withdrawn
- 2000-05-30 JP JP2000159463A patent/JP2001024584A/en not_active Withdrawn
- 2000-06-08 CA CA002311023A patent/CA2311023A1/en not_active Abandoned
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2021190031A1 (en) * | 2020-03-25 | 2021-09-30 | 京信网络***股份有限公司 | Wdm-based data transmission method, apparatus, and system, and storage medium |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2001024584A (en) | 2001-01-26 |
| EP1061685A8 (en) | 2001-05-16 |
| DE19927451A1 (en) | 2000-12-21 |
| EP1061685A2 (en) | 2000-12-20 |
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| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Discontinued |