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BY- SUNEET SRIVASTAVA

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History of Fiber Optic Transmission

Types of Multiplexing

Principle of WDM

WDM Technology

WDM Components

Transmission Challenges

Future Scope

Application

Conclusion

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EVOLUTION OF FIBER

OPTIC TRANSMISSION In mid 1960s researchers proposed optical

fiber as suitable transmission medium.

In 1970 , Corning produced the firstcommunicationgrade fibers.

AT& T first standardized transmission atDS3 speed(45Mbps) for multimode fibers.

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Thereafter, single mode fibers were shown to be

capable of transmission rates 10 times that ofolder type.

These regions called windows, lie between

area of high absorption.

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5

Fiber Characteristics

1550Window

1310Window

O - band E - band S - band C - band L - band

1280 1320 1360 1400 1440 1480 1520 1560 16001552Wavelength

(nm)

CWDM Window

DWDM Window

C Band Range : 1530nm

1560nmL Band Range : 1570nm 1600nm

Water Peak

WINDOWS

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WHAT ACTUALLY IS MULTIPLEXING ?

MULTIPLEXING (also known as muxing)

is a method by which multiple analog

message signals or digital data streamsare combined into one signal over a

shared medium.

a device that performs the multiplexing is

called a multiplexer (mux), and a device

that performs the reverse process is

called a demultiplexer (demux).

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Time Division Multiplexing

Frequency Division multiplexing

Code Division Multiplexing Wavelength Division multiplexing

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PROBLEM:

DEMAND FOR MASSIVE INCREASES IN CAPACITY

IMMEDIATE SOLUTION:

WAVELENGTH DIVISION MULTIPLEXING

LONGER TERM SOLUTION:

OPTICAL FIBRE NETWORKS

PROBLEMS AND SOLUTIONS

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LIGHTWAVE SYSTEM

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Colors are transmitted through air and may

mixThese colors can be easily separated by

prism

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PRINCIPLE

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ADVANTAGES OF WDM

Unlimited Transmission Capacity

Transparency

Scalability

Dynamic Provisioning

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IS WDM FLEXIBLE?

Fiber Cable

WDM Fiber MUX

Independent

opticial bitrates

and formats

GE

SONET

Fiber Channel

ATM

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IS WDM EXPANDABLE?

Incremental capacity expansion to 80 Gbits/sand beyond

Allows reuse of the installed equipment base

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TYPES OF WDM

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WDM SYSTEM

Block Diagram of DWDM System

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WDM COMPONENTS

l1l2

l3

l1l2l3

l1...nl1...n

lens

prism

prismlensFiber optic

Light source Photo detector

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LIGHT SOURCES LED (light emitting diode)

LASER (Light Amplification by Stimulated

Emission of Radiation)

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WDM COMPONENTS

Optical Multiplexer

Optical De-multiplexer

Optical Add/Drop Multiplexer(OADM)

l1l2l3

l1l2l3

Transponder

850/1310 15xx

l1l2

l3

l1...n

l1...n

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WDM SYSTEM

CHARACTERISTICSComponent reliabilitySystem availability

System margin.

System wavelength and bit rate can be upgraded

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TRANSMISSION

CHALLENGESAttenuation Attenuation is caused by :

- intrinsic factors primarily scattering

and absorption- extrinsic factors, including stress fromthe manufacturing process, theenvironment, and physical bending

Rayleigh scattering - is an issue atshorter wavelengths

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RAYLEIGH SCATTERING

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Attenuation due to absorption

- is an issue at longer wavelengths

- the intrinsic properties of the material

- impurities in the glass, and any atomic

defects in the glass.

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Absorption

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DISPERSION Spreading of light pulses

Two general types of dispersion

Chromatic Dispersion - is linear

Polarization Mode Dispersion - is nonlinear.

FUTURE OF WDM

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FUTURE OF WDM

What the future holds

Two-way video communication

Digital video for our everyday use

The Ultimate Squeeze- reducing the space between wavelengths- expanding the range of transmission

wavelengths- better EDFAs

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Develop better equipment

Cheap WDM pipelines

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APPLICATIONS OF WDM

Long-distance telecommunications

Building or expanding networks

Network wholesalers can lease capacity

Utilize the existing thin fiber

DWDM improves signal transmission

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New technology for utilization of bandwidth

Ultra high speed data rate

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