1 Improving Chromatic Dispersion Tolerance in Long-Haul Fibre Links using Coherent OOFDM M. A. Jarajreh, Z. Ghassemlooy, and W. M. A. Jarajreh, Z. Ghassemlooy, and W. P. Ng P. Ng Optical Communications Research Group Optical Communications Research Group http://soe.unn.ac.uk/ocr/ School of Computing, Engineering and Information School of Computing, Engineering and Information Sciences Sciences University of Northumbria at Newcastle, University of Northumbria at Newcastle, UK UK
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Improving Chromatic Dispersion Tolerance in Long-Haul Fibre Links
using Coherent OOFDM
M. A. Jarajreh, Z. Ghassemlooy, and W. P. NgM. A. Jarajreh, Z. Ghassemlooy, and W. P. Ng
Optical Communications Research GroupOptical Communications Research Grouphttp://soe.unn.ac.uk/ocr/
School of Computing, Engineering and Information School of Computing, Engineering and Information SciencesSciences
University of Northumbria at Newcastle, University of Northumbria at Newcastle, UKUK
Contents OFDM and Optical OFDM (OOFDM) Applications of OOFDM Modems Coherent -OOFDM (CO-OOFDM)Modems Design CO-OOFDM Modems - Modelling (Matlab and VPi) Motivation Results
Back-to-Back Performance Back-to-Back Performance Effect of Number of Sub-carriers and CP on CD ToleranceEffect of Number of Sub-carriers and CP on CD Tolerance Effect of Number of Sub-carriers ON Transmission performanceEffect of Number of Sub-carriers ON Transmission performance Effect of Sampling Speed on CD ToleranceEffect of Sampling Speed on CD Tolerance Effect of Sampling Speed on Transmission Performance in Fibre LinksEffect of Sampling Speed on Transmission Performance in Fibre Links The Effect of Adaptively Modulated CO-OOFDM on CD ToleranceThe Effect of Adaptively Modulated CO-OOFDM on CD Tolerance
Conclusions
OFDM
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Orthogonal Frequency Division Multiplexing (OFDM)
Harmonically related narrowband sub-carriers The sub-carriers spaced by 1/Ts The peak of each sub-carrier coincides with trough of
other sub-carriers
Splitting a high-speed data stream into a number of low-speed streams
Different sub-carrier transmitted simultaneously
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What is OOFDM By introducing OFDM in the optical domain, Optical OFDM
(OOFDM) was generated
Advantages of OOFDM Cost-effective High-speed Excellent flexibility and robustness
Combating optical fibers dispersion and polarization mode dispersion
Applications of OOFDM Modems
Coherent -OOFDM Modems Design
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CO-OOFDM modem diagram used in numerical simulations, (dotted line is either fibre or integrated optics)
CO-OOFDM Modems - Modelling Matlab: easy to model the OFDM modem
32-QAM modulation
32-QAM detection with additive noise
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-5 -4 -3 -2 -1 0 1 2 3 4 5-5
-4
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-1
0
1
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REAL
IMA
G
-8 -6 -4 -2 0 2 4 6 8-8
-6
-4
-2
0
2
4
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REAL
IMA
G
CO-OOFDM Modems – Modelling
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Screen shots (Coherent OFDM System)
(Virtual Photonic Inc.) VPi Software
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• The achievable signal transmission capacity of an Optical Orthogonal Frequency Division Multiplexing (OOFDM) modem over Single Mode Fibre (SMF) links is affected considerably by:• Fibre Chromatics Dispersion (CD)
• Number of sub-carriers• Cyclic prefix
• Fibre nonlinearity• Optical launch power
• Numerical simulations are undertaken to investigate the above-mentioned effects on the system performance of Coherent OOFDM
Motivation
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Results
Work will be presented
Back-to-back Performance
Effect of number of subcarriers and Cyclic Prefix (CP) on Chromatic Dispersion (CD) Tolerance
Effect of sampling speed on CD tolerance
The result of utilizing AM-CO-OOFDM on CD tolerance
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Simulation ParametersParameters Values
No. of subcarriers 64Wavelength 1550 nmLight source Laser diode