WO2000018047A2 - Pre- and post-compensation techniques for wavelength division multiplexing systems - Google Patents
Pre- and post-compensation techniques for wavelength division multiplexing systems Download PDFInfo
- Publication number
- WO2000018047A2 WO2000018047A2 PCT/US1999/022009 US9922009W WO0018047A2 WO 2000018047 A2 WO2000018047 A2 WO 2000018047A2 US 9922009 W US9922009 W US 9922009W WO 0018047 A2 WO0018047 A2 WO 0018047A2
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- dispersion
- dwdm
- optimized
- fiber
- wavelength division
- Prior art date
Links
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
- H04B10/2513—Arrangements specific to fibre transmission for the reduction or elimination of distortion or dispersion due to chromatic dispersion
- H04B10/2525—Arrangements specific to fibre transmission for the reduction or elimination of distortion or dispersion due to chromatic dispersion using dispersion-compensating fibres
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B2210/00—Indexing scheme relating to optical transmission systems
- H04B2210/25—Distortion or dispersion compensation
- H04B2210/252—Distortion or dispersion compensation after the transmission line, i.e. post-compensation
-
- 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
- This invention relates to wavelength division multiplexers (WDMs) systems and, more particularly, to dense WDMs (DWDMs), in which dispersion compensation is utilized at both the receiver and transmitter ends, and further wherein a WDM is optimized overall.
- WDMs wavelength division multiplexers
- DWDMs dense WDMs
- dispersion compensation techniques at either the receiver or transmitter ends of a wavelength division multiplexer have been of interest.
- This invention pertains to the simultaneous use of dispersion compensation at both the receiver (RX) and transmitter (TX) ends of a dense WDM to obtain better performance.
- the invention provides techniques for optimizing dual dispersion compensation, given the characteristics of the overall WDM and its associated network.
- One factor significantly affecting the optimum ratio for dispersion compensation at the RX and TX ends is the chirp value of the transmitter. Other factors include power level, number of channels, channel plan, fiber dispersion, and system length.
- Providing dispersion compensation simultaneously at both the RX and TX ends of the WDM system can produce superior results compared with compensation at a single end.
- the type and distribution of the dispersion (dispersion ratio) between the RX and TX ends must be balanced for the particular system. If not properly balanced, the results can be inferior even to those for single ended compensation.
- FIGURE 2 depicts a diagrammatic view of the spectra obtained for the fiber optic system shown in FIGURE 1 ;
- FIGURE 4 illustrates a graphical view of Q versus channel number compared with the FWM spectrum for the same channels for the fiber optic system depicted in FIGURE 1;
- FIGURE 5a shows a graphical view of Q, as a function of wavelength, for the fully assembled system (squares), together with the Q measured with transmission fiber having been replaced by attenuators (circles); and
- FIGURE 5b depicts a graphical view of the penalty of the fiber (dB) vs. the wavelength (nm).
- the invention features a long haul, broadband, DWDM system that has been optimized by the proper selection of the distribution of total dispersion compensation.
- Dispersion compensation is utilized at both the receiver and transmitter ends.
- System performance is dependent on the ratio of compensation split between the transmitter and the receiver.
- a system operated in the nonlinear regime can be compensated to operate at low BER and with tolerable residual dispersion effects, even when the spread of total accumulated dispersion between the extreme channels in a broadband system exceeds 1,100 ps/nm.
- FIGURE 1 a schematic diagram shows a typical DWDM system in accordance with this invention.
- the system is of the long haul type, and designed to be deployable terrestrially.
- the system utilizes DFB lasers comprising thirty-two channels on an ITU grid.
- the optical amplifiers disposed at the input to each span were characterized by a 25 dB external gain, total power output of 20 dBm (19 dBm directed into the fiber spans), an average noise figure of 5 dB, and an average gain ripple of 1.2 dB.
- Commercial units of Dispersion Compensating Modules were provided as DCM-X, where X was the equivalent length in kilometers of standard single mode fiber dispersion, compensated by the dispersion compensating module.
- the DCM modules were applied at the transmitter and receiver ends.
- rows one and three have the same total compensations and the same is true for rows two and four, yet the system performances are markedly different depending on the rations of the pre- and post-compensation values.
- the lasers were multiplexed with fiber couplers, and modulated with a 2 3l -l , 10 GBit/s pseudorandom bit stream (PRBS) by a Li:NbO 3 , zero-chirp, Mach-Zehnder modulator.
- PRBS pseudorandom bit stream
- the lasers match the ITU-T nominal central frequency grid and minimal channel spacing of 100 GHz.
- the signals were transmitted over a 450 km transmission line consisting of 5 x 90 km spans of LEAF ® large effective aperture fiber and four in-line optical amplifiers.
- LEAF ® fiber has an effective area of 72-78 ⁇ m , which is about 50% larger than typical NZ-DSF.
- the fibers ⁇ o varied between 1506 nm and 1514 nm, and dispersion slope was « 0.1 ps/nm /km.
- VOA Variable Optical Attenuator
- the span loss was increased to 24 dB by adding optical attenuators before each amplifier in order to simulate real system loss margin needed for real systems.
- a variable optical attenuator was used to keep the power substantially constant into the O-E converter.
- the input spectrum before the first VOA and output spectrum before the optical preamplifier are shown in FIGURE 2.
- the same amount of pre- and post-compensation was used for all channels.
- the total accumulated dispersion for the first channel was -454.78 ps/nm and +893.81 ps/nm for the last channel.
- the transmission performance was characterized by measuring the bit error rate as a function of the decision threshold for each channel.
- the system Q was estimated using the full system (fiber + amplifiers) and with fiber spans replaced by attenuators with equivalent loss. The results of the measurements for the full system are illustrated in FIGURE 3. The average Q for the full system was approximately 8.9 dB optical
- FWM Four Wave Mixing
- XPM Cross-Phase Modulation
- SPM Self-Phase Modulation
- NZ-DSF non-zero dispersion-shifted fibers
- the span loss was increased to 24 dB by adding optical attenuators before each amplifier.
- An etalon filter with an FWHM of 0.3 nm at the optical pre-amplifier selected the channel to be measured.
- Optical pre-emphasis was required to equalize the received optical signal-to- noise ratio at the end of the transmission line for the red band experiment.
- Four Wave Mixing (FWM) was not observed in either the red or the blue experiment.
- the large effective aperture fiber effectively suppresses FWM in dense WDM systems. Furthermore, due to its large effective area and small dispersion, this fiber allows for the minimization of self- and cross-phase modulation penalties at 10 Gbit s, using dispersion compensation at the terminal. This eliminates the need for dispersion management in the cable or at every amplifier.
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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
Description
Claims
Priority Applications (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP99948398A EP1142178A2 (en) | 1998-09-21 | 1999-09-21 | Wavelength division multiplexing systems |
CA002344543A CA2344543A1 (en) | 1998-09-21 | 1999-09-21 | Wavelength division multiplexing systems |
AU61588/99A AU6158899A (en) | 1998-09-21 | 1999-09-21 | Wavelength division multiplexing systems |
JP2000571593A JP2002525967A (en) | 1998-09-21 | 1999-09-21 | Wavelength division multiplexing system |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US10124198P | 1998-09-21 | 1998-09-21 | |
US60/101,241 | 1998-09-21 |
Publications (2)
Publication Number | Publication Date |
---|---|
WO2000018047A2 true WO2000018047A2 (en) | 2000-03-30 |
WO2000018047A3 WO2000018047A3 (en) | 2000-05-25 |
Family
ID=22283663
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/US1999/022009 WO2000018047A2 (en) | 1998-09-21 | 1999-09-21 | Pre- and post-compensation techniques for wavelength division multiplexing systems |
Country Status (6)
Country | Link |
---|---|
EP (1) | EP1142178A2 (en) |
JP (1) | JP2002525967A (en) |
CN (1) | CN1323475A (en) |
AU (1) | AU6158899A (en) |
CA (1) | CA2344543A1 (en) |
WO (1) | WO2000018047A2 (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP1303062A2 (en) * | 2001-10-09 | 2003-04-16 | Nortel Networks Limited | Distortion measurement in optical communications systems |
CN1326339C (en) * | 2000-09-06 | 2007-07-11 | 康宁股份有限公司 | Dispersion map for slope compensating fibers |
US7379670B2 (en) | 2002-03-21 | 2008-05-27 | Tyco Telecommunications (Us) Inc. | Method and apparatus for chromatic dispersion compensation |
Families Citing this family (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP3934513B2 (en) * | 2002-08-29 | 2007-06-20 | 富士通株式会社 | Pre-emphasis control method considering nonlinear degradation |
CN101179338B (en) * | 2006-11-10 | 2012-02-29 | 中兴通讯股份有限公司 | Large dispersion compensating method of optical transmission system |
CN101989879B (en) * | 2009-08-05 | 2013-09-11 | 华为技术有限公司 | Electronic dispersion compensation method, device and system in burst mode |
Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5815294A (en) * | 1994-08-02 | 1998-09-29 | Fujitsu Limited | Optical transmission system with transmission characteristic measuring device |
US5877881A (en) * | 1996-04-19 | 1999-03-02 | Fujitsu Ltd. | Optical transmission system |
US5880876A (en) * | 1993-09-03 | 1999-03-09 | Hitachi, Ltd. | Optical transmission system |
US5886804A (en) * | 1995-03-31 | 1999-03-23 | Fujitsu Limited | Optical transmission system employing single mode optical transmission fiber |
-
1999
- 1999-09-21 CN CN 99811195 patent/CN1323475A/en active Pending
- 1999-09-21 WO PCT/US1999/022009 patent/WO2000018047A2/en not_active Application Discontinuation
- 1999-09-21 EP EP99948398A patent/EP1142178A2/en not_active Withdrawn
- 1999-09-21 AU AU61588/99A patent/AU6158899A/en not_active Abandoned
- 1999-09-21 JP JP2000571593A patent/JP2002525967A/en not_active Withdrawn
- 1999-09-21 CA CA002344543A patent/CA2344543A1/en not_active Abandoned
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5880876A (en) * | 1993-09-03 | 1999-03-09 | Hitachi, Ltd. | Optical transmission system |
US5815294A (en) * | 1994-08-02 | 1998-09-29 | Fujitsu Limited | Optical transmission system with transmission characteristic measuring device |
US5886804A (en) * | 1995-03-31 | 1999-03-23 | Fujitsu Limited | Optical transmission system employing single mode optical transmission fiber |
US5877881A (en) * | 1996-04-19 | 1999-03-02 | Fujitsu Ltd. | Optical transmission system |
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN1326339C (en) * | 2000-09-06 | 2007-07-11 | 康宁股份有限公司 | Dispersion map for slope compensating fibers |
EP1303062A2 (en) * | 2001-10-09 | 2003-04-16 | Nortel Networks Limited | Distortion measurement in optical communications systems |
EP1303062A3 (en) * | 2001-10-09 | 2005-02-09 | Nortel Networks Limited | Distortion measurement in optical communications systems |
US7606487B1 (en) | 2001-10-09 | 2009-10-20 | Nortel Networks Limited | Distortion measurement in optical communication systems |
US7379670B2 (en) | 2002-03-21 | 2008-05-27 | Tyco Telecommunications (Us) Inc. | Method and apparatus for chromatic dispersion compensation |
Also Published As
Publication number | Publication date |
---|---|
WO2000018047A3 (en) | 2000-05-25 |
JP2002525967A (en) | 2002-08-13 |
EP1142178A2 (en) | 2001-10-10 |
AU6158899A (en) | 2000-04-10 |
CN1323475A (en) | 2001-11-21 |
CA2344543A1 (en) | 2000-03-30 |
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