This presentation provides an overview of Dense Wavelength Division Multiplexing (DWDM) technology. It begins with an introduction to optical fiber transmission systems and their evolution. It then discusses the basic principles and components of DWDM, including terminal multiplexers and demultiplexers, optical amplifiers, and optical add-drop multiplexers. DWDM allows numerous wavelengths to be transmitted simultaneously, greatly increasing network capacity. Key benefits of DWDM include scalability and the ability to add additional capacity without laying more fiber. Nonlinear effects present challenges but recent advances have achieved transmission capacities over 20 terabits per second. Overall, DWDM plays a crucial role in high-capacity optical networks.

1. MINI PROJECT PRESENTATION
Prepared By:
Hasna Heng Kamal Koh
0911796
Hasna Heng

2. DENSE WAVELENGTHDIVISION MULTIPLEXING
(DWDM)
An Evolution of Optical Fiber Transmission
System
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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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4. INTRODUCTION OF
OPTICAL FIBER
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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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10. RESOLVING THE
BANDWIDTH DEMAND
INTORDUCING TDM & WDM
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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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13. TDM
Input Signals
Output Signals
WDM
Input Signals
Output Signals
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14. WDM

Coarse WDM (CWDM)
Wide channel spacing (20nm)
 Up to 16 wavelengths
 Low cost


Dense WDM (DWDM)
Dense channel spacing (0.2nm)
 Allows numerous wavelength transmission
simultaneously – high capacity

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15. DENSE WAVELENGTHDIVISION MULTIPLEXING
DWDM
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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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17. Hasna Heng

18. MAIN COMPONENTS IN DWDM
Terminal Multiplexer (MUX)
Intermediate Line Repeater
1.
2.


3.
4.
Optical Amplifier
Erbium-Doped Fiber Amplifier (EDFA)
Optical Add/Drop Multiplexer (OADM)
Terminal De-multiplexer (DEMUX)
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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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22. 16 fiber pairs + 128 generators
 1 fiber pair + 16 Optical Amplifier

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23. ERBIUMDOPED
FIBER
AMPLIFIER
(EDFA)

Significant breakthrough for DWDM
system (1995)
Larger power output
 Minimize noise factor
 Operates on wide bandwidth network
 No data format restriction

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24. ENERGY-LEVEL DIAGRAM
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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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27. 4. DEMUX


Inverse function of
MUX
Multiple-wavelengths
signals  individual
signals
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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 !!
Hasna Heng

32. BIBLIOGRAPHY
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(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.
Hasna Heng

33. Hasna Heng