3. Objectives
To have a basic understanding on optical fiber
transmission system
To understand the basic principle of the DWDM
technology
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5. OPTICAL FIBER
Fine threads of glass in layers
Diameter ≈ human hair
Core & Cladding + protection layers (polymers)
2 types of fiber profiles
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6. STEPPED-INDEX FIBER
Multimode Fiber
Larger core (50-200µm)
Simultaneously transmit
numerous mode of light
1st generation system
(1975-1980)
Single-mode Fiber
Small core (<10µm)
Carries single mode of
light
Eliminate intermodal
dispersion
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7. GRADED-INDEX FIBER
Multimode Fiber
Average velocity of all light rays approximately same
Light bent parabolic light wave
Higher bandwidth
Better compensation with dispersion
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8. OPTICAL CARRIER
Optical Carrier
Line Rate
(Mb/s)
OC-1
51.84
OC-3
155.52
OC-12
622.08
OC-48
2,488.32
OC-192
9.953.28
OC-768
Standardized set of
specification of Tx
bandwidth
digital signal carried
on SONET/SDH use
terms STS-n/STM-n
Optical signals: OC-n
39,813.12
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9. WHY MOVE TO OPTICAL FIBER?
Copper Wiring
Optical Fiber
Expensive material
High power
consumption
Large and heavy
Weak signal due to
power degradation
Low signal capacity
Stealing cases
Low cost on
installation
Low cost material
Lower power
consumption
Smaller size & lighter
Minimize degradation of
signal
Large data capacity
Expensive for
construction and
installation
Less flexible easily
damaged
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11. Statistical studies: Annual growth of the internet
= 40% !!
Upsurge of emerging services: 3G, broadband,
integrated multimedia services etc.
Network traffic became sophisticated
Increasing bandwidth demands
Internet growth
2 solutions:
Time-Division Multiplexing (TDM)
Wavelength-Division Multiplexing (WDM)
40%/year
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12. TDM
Increase the bit rate
data
Input data
Arrange in
sequence
Output
WDM
Increase the wavelength
Input
wavelength
Combine &
Split
Wavelength
Output
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16. DWDM TECHNOLOGY
Multiplex multiple signals on single optical fiber
using different wavelength
Channel signals carried by its wavelength
Using C-band (1550nm) or L-band (1625nm)
(Early development)
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19. 1. TERMINAL MULTIPLEXER (MUX)
Transponder
O-E-O conversion
Each can convert one wavelength signal
Covert input signals into C-band laser
MUX
Combined multiple data streams into a single data
channel to be transmitted
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20. 2. INTERMEDIATE LINE REPEATER
Booster for transmission signals
To overcome the issue of attenuation on a longhaul network
Installed every 80-100km
Traditional amplifier need O-E conversion
Costly
Signal noise
Format restriction
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21. TYPICAL OPTICAL AMPLIFIER
Don’t need electrical regeneration
Independence of data format
Speed increment
Eg: Raman effect amplifier, semiconductor
optical/laser amplifier (SOA/SLA)
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25. 3. OPTICAL ADD/DROP MULTIPLEXER
(OADM)
aka Intermediate optical terminal
Allows wavelength to be added/dropped from the
signal as other wavelength passes through
Can substitute optical amplifier
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26. ROADM
Disadvantages of OADM:
Inserting/replacing Wavelength-selective card manually
Costly
Optical signal interrupted
Hence Reconfigurable OADM (ROADM)
Switching wavelength configuration by remote
Efficient & cost-effective
More advanced OADM: the enhanced ROADM
(eROADM)
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28. WHY MOVE TO DWDM?
Capacity upgrade w/o adding fibers
Transparency – can carry any transmission
format
Scalability – Install additional equipment as
needed
Wavelength routing and switching – wavelength
is used as another dimension to time and space
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29. ISSUES IN DWDM
Attenuation
Nonlinear inelastic scattering processes
Stimulated Raman Scattering (SRS)
Stimulated Brillion Scattering (SBS)
Nonlinear variations in the refractive index due to
varying light intensity
Self Phase Modulation (SPM)
Cross Phase Modulation (XPM)
Four Wave Mixing (FWM)
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30. LATEST ACHIEVEMENTS
HuaWei Global leading ICT solution provider
Pioneer in 100G DWDM
16 commercials + 50 trials of 100G networks
Recently: World’s first 400G long-haul DWDM system
(super channels)
Capacity up to 20Tbps over C-band
Transmission distance spanning 1000km w/o electrical
regeneration
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31. CONCLUSION
DWDM plays an essential role in high capacity
optical networks
Theoretically, enormous capacity is possible
No communication system is as terrific as our
communication with our Creator, Allah the
Almighty.
No cost
No limitation
100% guaranteed !!
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32. BIBLIOGRAPHY
(n.d.). Retrieved from http://technologyinside.com/2007/03/30/making-sdh-dwdm-and-packetfriendy/
Ciena Corporation. (1997). Dense Wavelength Division Multiplexing. Natick: The Applied
Technologies Group.
Cisco Systems Inc. (2001, June 4). Introduction to DWDM Technology. Retrieved from
http://www.cisco.com/application/pdf/en/us/guest/products/ps2011/c2001/ccmigration_09186a00802
342cf.pdf
EXFO Inc. (n.d.). EXFOTube. Retrieved from www.youtube.com:
http://www.youtube.com/user/EXFOTube/
Fiber Optics For Sale Co. (n.d.). Retrieved from fiberoptics4sale:
http://www.fiberoptics4sale.com/wordpress/
Kartalopoulos, S. V. (2003). Optical Components and Optics. Retrieved from Global Spec:
http://beta.globalspec.com/reference/21551/160210/chapter-4-2-dwdm-network-topologies-review
Radmer, H. (2007). Basic DWDM Components. Retrieved from
http://www.nordu.net/development/fiber-workshop2007/Basic-DWDM-Components.pdf
Rahman, A. (n.d.). A Review of DWDM - The Heart of Optical Networks. Retrieved from
http://home.comcast.net/~dwdm2/DWDM_Review.PDF
Senior, J. M. (2009). Optical Fiber Communications - Principles and Practice (3rd ed.). Harlow:
Pearson Education Limited.
Song, S. (2001). An Overview of DWDM Networks. IEEE Canadian Review.
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