MINI PROJECT PRESENTATION

Prepared By:

Hasna Heng Kamal Koh

0911796

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DENSE WAVELENGTH-DIVISION MULTIPLEXING

(DWDM)

An Evolution of Optical Fiber Transmission

System

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Objectives

To have a basic understanding on optical fiber

transmission system

To understand the basic principle of the DWDM

technology

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OPTICAL FIBER

INTRODUCTION OF

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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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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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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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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 39,813.12

Standardized set of

specification of Tx

bandwidth

digital signal carried

on SONET/SDH use

terms STS-n/STM-n

Optical signals: OC-n

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WHY MOVE TO 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

Copper Wiring Optical Fiber

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RESOLVING THE BANDWIDTH DEMAND INTORDUCING TDM & WDM

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40%/year

Internet growth

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

2 solutions:

Time-Division Multiplexing (TDM)

Wavelength-Division Multiplexing (WDM)

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Increase the bit rate

data

Increase the wavelength

TDM WDM

Input data

Arrange in sequence

Output

Input wavelength

Combine & Split

Wavelength

Output

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WDM

Input Signals Output Signals

Output Signals

TDM

Input Signals

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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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DENSE WAVELENGTH-DIVISION MULTIPLEXING DWDM

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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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MAIN COMPONENTS IN DWDM

1. Terminal Multiplexer (MUX)

2. Intermediate Line Repeater

Optical Amplifier

Erbium-Doped Fiber Amplifier (EDFA)

3. Optical Add/Drop Multiplexer (OADM)

4. Terminal De-multiplexer (DEMUX)

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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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2. INTERMEDIATE LINE REPEATER Booster for transmission signals

To overcome the issue of attenuation on a long-

haul network

Installed every 80-100km

Traditional amplifier need O-E conversion

Costly

Signal noise

Format restriction

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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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16 fiber pairs + 128 generators

1 fiber pair + 16 Optical Amplifier

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ERBIUM-DOPED 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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ENERGY-LEVEL DIAGRAM

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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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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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4. DEMUX Inverse function of

MUX

Multiple-wavelengths signals individual signals

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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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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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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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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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BIBLIOGRAPHY (n.d.). Retrieved from http://technologyinside.com/2007/03/30/making-sdh-dwdm-and-packet-

friendy/

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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