WAVELENGTH DIVISION

MULTIPLEXING

BY- FG OFFR SUNEET SRIVASTAVA

CONTENTHistory of Fiber Optic TransmissionTypes of MultiplexingPrinciple of WDMWDM TechnologyWDM ComponentsTransmission ChallengesFuture ScopeApplicationConclusion

EVOLUTION OF FIBER OPTIC TRANSMISSION

• In mid 1960’s researchers proposed optical fiber as suitable transmission medium.

• In 1970 , Corning produced the first communication –grade fibers.

• AT& T first standardized transmission at DS3 speed(45Mbps) for multimode fibers.

•Thereafter, single mode fibers were shown to be capable of transmission rates 10 times that of older type.

•These regions called windows, lie between area of high absorption.

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

WHAT ACTUALLY IS MULTIPLEXING ?

MULTIPLEXING (also known as muxing) is a method by which multiple analog message signals or digital data streams are 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).

TYPES OF MULTIPLEXING• Time Division Multiplexing• Frequency Division multiplexing• Code Division Multiplexing• Wavelength Division multiplexing

PROBLEM:DEMAND FOR MASSIVE INCREASES IN CAPACITY

IMMEDIATE SOLUTION: WAVELENGTH DIVISION MULTIPLEXING

LONGER TERM SOLUTION:OPTICAL FIBRE NETWORKS

PROBLEMS AND SOLUTIONS

LIGHTWAVE SYSTEM

PRINCIPLE OF WDM

•Colors are transmitted through air and may mix•These colors can be easily separated by prism

PRINCIPLE

ADVANTAGES OF WDM

• Unlimited Transmission Capacity• Transparency• Scalability• Dynamic Provisioning

IS WDM FLEXIBLE?

Fiber Cable

WDM Fiber MUX

Independentopticial bit

ratesand formats

GE

SONET

Fiber Channel

ATM

IS WDM EXPANDABLE?

•Incremental capacity expansion to 80 Gbits/s and beyond

•Allows reuse of the installed equipment base

TYPES OF WDM

WDM SYSTEM

Block Diagram of DWDM System

WDM COMPONENTS

l1

l2l3

l1l2l3

l1...nl1...n

lens

prism

prismlens

Fiber optic

Light source Photo detector

LIGHT SOURCES

LED (light emitting diode)

LASER (Light Amplification by

Stimulated Emission of Radiation)

19

WDM COMPONENTS

Optical Multiplexer

Optical De-multiplexer

Optical Add/Drop Multiplexer(OADM)

l1

l2

l3

l1

l2

l3

Transponder

850/1310 15xx

l1

l2

l3

l1...n

l1...n

WDM SYSTEM CHARACTERISTICS•Component reliability

•System availability

•System margin.

•System wavelength and bit rate can be upgraded

TRANSMISSION CHALLENGES

Attenuation• Attenuation is caused by :

- intrinsic factors primarily scattering and absorption- extrinsic factors, including stress from the manufacturing process, the environment, and physical bending

• Rayleigh scattering - is an issue at shorter wavelengths

RAYLEIGH SCATTERING

• 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.

Absorption

DISPERSION• Spreading of light pulses Two general types of dispersion

• Chromatic Dispersion - is linear • Polarization Mode Dispersion - is nonlinear.

FUTURE OF WDMWhat 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

• Develop better equipment

• Cheap WDM pipelines

APPLICATIONS OF WDM• Long-distance telecommunications

• Building or expanding networks

• Network wholesalers can lease capacity

• Utilize the existing thin fiber• • DWDM improves signal transmission

COCLUSIONNew technology for utilization of bandwidth

Ultra high speed data rate

THANK YOU