DENSE WAVELENGTH DENSE WAVELENGTH DIVISION MULTIPLEXINGDIVISION MULTIPLEXING

PRESNTED BY:PRESNTED BY:

1.NAVEEN TIWARI1.NAVEEN TIWARI

2.NAVEEN KUSHWAHA2.NAVEEN KUSHWAHA

3.MOHIT KUMAR3.MOHIT KUMAR

CONTENTSCONTENTS

IntroductionIntroductionDWDM TechnologyDWDM TechnologyDWDM System & ComponentsDWDM System & ComponentsTopologyTopologyTransmission ChallengesTransmission ChallengesMarket DynamicsMarket DynamicsFutureFutureApplicationsApplications

Electromagnetic SpectrumElectromagnetic Spectrum

INTRODUCTIONINTRODUCTION

One of the major issues in the networking industry One of the major issues in the networking industry today is tremendous demand fortoday is tremendous demand for

more and more bandwidth.more and more bandwidth.

With the development of Optical network and the With the development of Optical network and the use Dense Wavelength Division Technology, a new use Dense Wavelength Division Technology, a new

and probably, a very crucial milestone is being and probably, a very crucial milestone is being reached in network evaluation.reached in network evaluation.

OPTICAL NETWORKINGOPTICAL NETWORKING

Optical networks are high-capacity Optical networks are high-capacity telecommunications networks based on telecommunications networks based on optical technologies.optical technologies.

The origin of optical networks is linked to The origin of optical networks is linked to Wavelength Division Multiplexing (WDM) Wavelength Division Multiplexing (WDM) which arose to provide additional capacity which arose to provide additional capacity on existing fibers. on existing fibers.

CLASSIFICATION OF OPTICAL CLASSIFICATION OF OPTICAL NETWORKNETWORK

FIRST GENERATIONFIRST GENERATION: : Networks use Cu Networks use Cu based or microwave technology based.based or microwave technology based.

SECAND SECAND GENERATIONGENERATION: : Networks use Networks use

microwave links with optical fibers.microwave links with optical fibers.

THIRED GENERATIONTHIRED GENERATION: : Networks employNetworks employ

Wavelength Division Multiplexing technology. Wavelength Division Multiplexing technology.

What is DWDM?What is DWDM?

Dense Wavelength Division Multiplexing Dense Wavelength Division Multiplexing (DWDM) is a fiber-optic transmission(DWDM) is a fiber-optic transmission

technique. technique.

It involves the process of multiplexing many It involves the process of multiplexing many different wavelength signals onto a single different wavelength signals onto a single fiber. So each fiber has a set of parallel fiber. So each fiber has a set of parallel optical channels each using slightly different optical channels each using slightly different light wavelengths. light wavelengths.

It employs light wavelengths to transmit It employs light wavelengths to transmit data parallel-by-bit or serial-by-character.data parallel-by-bit or serial-by-character.

DWDM is a very crucial component of DWDM is a very crucial component of optical networks that will allow the optical networks that will allow the transmission of data: voice, video over the transmission of data: voice, video over the optical layer.optical layer.

It transmits multiple data signals using different It transmits multiple data signals using different wavelengths of light through a single fiber.wavelengths of light through a single fiber.

Incoming optical signals are assigned to specific Incoming optical signals are assigned to specific frequencies within a designated frequency band.frequencies within a designated frequency band.

The capacity of fiber is increased when these The capacity of fiber is increased when these signals are multiplexed onto one fibersignals are multiplexed onto one fiber

Transmission capabilities is 4-8 times of Transmission capabilities is 4-8 times of TDM Systems with the help of Erbium TDM Systems with the help of Erbium doped optical amplifier.doped optical amplifier.

EDFA’s : increase the optical signal and don’t EDFA’s : increase the optical signal and don’t have to regenerate signal to boost it strength.have to regenerate signal to boost it strength.

It lengthens the distances of transmission to It lengthens the distances of transmission to more than 300 km before regeneration .more than 300 km before regeneration .

Why DWDM?Why DWDM?

Unlimited Transmission CapacityUnlimited Transmission Capacity

TransparencyTransparency

ScalabilityScalability

Dynamic ProvisioningDynamic Provisioning

Is DWDM Flexible?Is DWDM Flexible?

DWDM is a protocol and bit rate independent DWDM is a protocol and bit rate independent hence, data signals such as ATM, SONET and hence, data signals such as ATM, SONET and IP can be transmitted through same stream IP can be transmitted through same stream regardless their speed difference.regardless their speed difference.

The signals are never terminated within the The signals are never terminated within the optical layer allows the independence of bit rate optical layer allows the independence of bit rate and protocols,allowing DWDM technology to be and protocols,allowing DWDM technology to be integrated with existing equipment in network.integrated with existing equipment in network.

Hence, there’s a flexibility to expand capacity Hence, there’s a flexibility to expand capacity within any portion of their networks.within any portion of their networks.

Is DWDM Expandable?Is DWDM Expandable?

“ “ DWDM technology gives us the ability to DWDM technology gives us the ability to expand out fiber network rapidly to meet growing expand out fiber network rapidly to meet growing demands of our customer”, said Mike Flynn, demands of our customer”, said Mike Flynn, group President for ALLTEL’s communications group President for ALLTEL’s communications operations.operations.

DWDM coupled with ATM simplifies the network, DWDM coupled with ATM simplifies the network, reduce network costs and provide new services.reduce network costs and provide new services.

They can add current and new TDM systems to They can add current and new TDM systems to their existing technology to create a system with their existing technology to create a system with virtually endless capacity expansionvirtually endless capacity expansion

DISADVANTAGES

Not cost effective for low channel numbers

Sonet/sdh network management system

Are not well equipped to handle dwdm topologies

DWDM IllustratedDWDM Illustrated

Optical Nodes

Optical Amplifier

129,024 telephones

Data Sites

Optical Coupler

DWDM SYSTEMDWDM SYSTEM

Comparison of TDM, WDM, and Comparison of TDM, WDM, and DWDM multiplexing capabilitiesDWDM multiplexing capabilities

MultiplexMultiplex ScalableScalable ProtocolProtocol

indepenindependentdent

Bit rateBit rate

indepenindependentdent

ChanneChannels perls per

optical optical fiberfiber

OpticalOptical

systemsystem

capacitycapacity

EquivalEquivalent DS-3ent DS-3

connectconnectionsions

TDMTDM NoNo NoNo NoNo 11 2.5 2.5 Gbit/sGbit/s

4848

WDMWDM YesYes YesYes YesYes 22 5 Gbit/s5 Gbit/s 9696

DWDMDWDM YesYes YesYes YesYes 1616 N/A atN/A at

publicatipublicationon

N/A atN/A at

publicatipublicationon

A really cool analogyA really cool analogy

Think of the fiber as a multilane highwayThink of the fiber as a multilane highway Traditional TDM systems use only one lane, Traditional TDM systems use only one lane,

and to increase throughput, the cars speed up.and to increase throughput, the cars speed up.Because only one lane is used, only one type of Because only one lane is used, only one type of traffic can flow.traffic can flow.

DWDM networks allow traffic to use the rest of DWDM networks allow traffic to use the rest of the unused lanes.the unused lanes.

By using more lanes, different types of data can flow By using more lanes, different types of data can flow at different rates.at different rates.

A picture representing the really cool A picture representing the really cool analogyanalogy

Before

After TDM (cars go faster)

After DWDM (all the lanes are used)

Example of SpeedsExample of Speeds

Currently Lucent DWDM systems support Currently Lucent DWDM systems support transmissions of 160 separate transmissions of 160 separate wavelengths. Each wavelength is wavelengths. Each wavelength is capable of supporting a signal of up to 10 capable of supporting a signal of up to 10 Gbps.Gbps.

The total combined bandwidth is 1.6 The total combined bandwidth is 1.6 trillion bits per second.trillion bits per second.

This is greater than the speed of one This is greater than the speed of one million T-1 connections.million T-1 connections.

How DWDM saves $$How DWDM saves $$

In addition to saving money on fiber cables, In addition to saving money on fiber cables, DWDM also saves money on optical repeating DWDM also saves money on optical repeating equipmentequipment Because one fiber is used instead of many, one Because one fiber is used instead of many, one

repeater can be used in place of manyrepeater can be used in place of many For example: you need 16 OC-3 carrier lines to go For example: you need 16 OC-3 carrier lines to go

1000 miles and repeaters are needed every 100 1000 miles and repeaters are needed every 100 miles…miles…

If you didn’t use DWDM, you would need 16 thousand miles If you didn’t use DWDM, you would need 16 thousand miles of fiber and 160 repeatersof fiber and 160 repeatersWith DWDM, you need only 1 thousand miles of fiber and 10 With DWDM, you need only 1 thousand miles of fiber and 10 repeatersrepeaters

A picture of How DWDM saves $$A picture of How DWDM saves $$

Before DWDM

After DWDM

Signal QualitySignal Quality

Optical Signal to Noise RatioOptical Signal to Noise Ratio

Optical Spectrum AnalyzerOptical Spectrum Analyzer

Optical Signal

Noise Floor

Signal Degradation IllustratedSignal Degradation Illustrated

Optical Amplifier

First Noise FloorNoise Floor

Optical Signal

DWDM ComponentsDWDM Components

Transmitter : Laser with precise stable Transmitter : Laser with precise stable waveleng-th.waveleng-th.Link: Optical fiber that exhibits low loss and Link: Optical fiber that exhibits low loss and transmission performance in relevant transmission performance in relevant wavelength spectra.wavelength spectra.Receiver:Photo detectors and Optical Receiver:Photo detectors and Optical demultiple-xers using thin film filters or diffractive demultiple-xers using thin film filters or diffractive elements.elements.Optical add/drop multiplexers and optical cross Optical add/drop multiplexers and optical cross connect components.connect components.

DWDM Point to PointDWDM Point to Point

DWDM Mesh DesignsDWDM Mesh Designs

Advantages of DWDM Point to Advantages of DWDM Point to Point SystemsPoint Systems

TheThe DWDM point-to-point architecture is simple DWDM point-to-point architecture is simple to build and troubleshootto build and troubleshoot . .

It enables protocol transparency, increme-ntal It enables protocol transparency, increme-ntal growth, and capacity expansion over time, while growth, and capacity expansion over time, while dramatically reducing start-up costsdramatically reducing start-up costs. .

Point-to-point solutions are also extremely Point-to-point solutions are also extremely efficient.efficient.

No amplifiers or additional equipment required.No amplifiers or additional equipment required.

DWDM System CharacteristicsDWDM System Characteristics

Well-engineered DWDM systems offer Well-engineered DWDM systems offer component reliability, system availability, and component reliability, system availability, and system margin. Although filters were often system margin. Although filters were often susceptible to humidity, this is no longer the susceptible to humidity, this is no longer the case.case.An optical amplifier has two key elements: the An optical amplifier has two key elements: the optical fiber that is doped with the element optical fiber that is doped with the element erbium and the amplifier. erbium and the amplifier. Automatic adjustment of the optical amplifiers Automatic adjustment of the optical amplifiers when channels are added or removed achieves when channels are added or removed achieves optimal system performance.optimal system performance.

In the 1530- to 1565-nm range, silica-In the 1530- to 1565-nm range, silica-based optical amplifiers with filters and based optical amplifiers with filters and fluoride-based optical amplifiers perform fluoride-based optical amplifiers perform equally well.equally well.The system wavelength and bit rate can The system wavelength and bit rate can be upgraded but planning for this is be upgraded but planning for this is critical. critical.

Transmission ChallengesTransmission Challenges

AttenuationAttenuation

Attenuation is caused by :Attenuation is caused by :- intrinsic factors primarily scattering and - intrinsic factors primarily scattering and absorptionabsorption- extrinsic factors, including stress from - extrinsic factors, including stress from the manufacturing process, the the manufacturing process, the environment, and physical bendingenvironment, and physical bending

Rayleigh scatteringRayleigh scattering - is an issue at - is an issue at shorter wavelengthsshorter wavelengths

Rayleigh ScatteringRayleigh Scattering

Attenuation due to absorptionAttenuation due to absorption

- is an issue at longer wavelengths - is an issue at longer wavelengths - the intrinsic properties of the material - the intrinsic properties of the material - impurities in the glass, and any atomic - impurities in the glass, and any atomic defects in the glass. defects in the glass.

These impurities absorb the optical These impurities absorb the optical energy, causing the light to become energy, causing the light to become dimmer.dimmer.

AbsorptionAbsorption

DispersionDispersion

Dispersion is the spreading of light pulses as they travel Dispersion is the spreading of light pulses as they travel down optical fiber. Dispersion results in distortion of the down optical fiber. Dispersion results in distortion of the signal, which limits the bandwidth of the fiber.signal, which limits the bandwidth of the fiber.

Two general types of dispersionTwo general types of dispersionChromatic Dispersion - Chromatic Dispersion - is linear is linear

Chromatic dispersion occurs because different Chromatic dispersion occurs because different wavelengths propagate at different speeds. wavelengths propagate at different speeds.

Increases as the square of the bit rate. Increases as the square of the bit rate.

Polarization Mode Dispersion - Polarization Mode Dispersion - is nonlinear. is nonlinear.

Polarization mode dispersion (PMD) is caused by ovality Polarization mode dispersion (PMD) is caused by ovality of the fiber shape as a result of the manufacturing of the fiber shape as a result of the manufacturing process or from external stressors. process or from external stressors.

Changes over time Changes over time PMD is generally not a problem at speeds below OC-PMD is generally not a problem at speeds below OC-192.192.

Smearing of the signalSmearing of the signal

Fiber Non Linear tiesFiber Non Linear ties

Because nonlinear effects tend to manifest themselves Because nonlinear effects tend to manifest themselves when optical power is very high, they become important when optical power is very high, they become important in DWDM.in DWDM.

These nonlinearities fall into two broad groups:These nonlinearities fall into two broad groups:

- scattering phenomena- scattering phenomena

- refractive index phenomena- refractive index phenomena

Scattering PhenomenaScattering Phenomena - - Stimulated Brillouin Scattering (SBS)Stimulated Brillouin Scattering (SBS) - Stimulated Raman Scattering (SRS) - Stimulated Raman Scattering (SRS) SolutionSolution

use moderate channel powers and densely packed use moderate channel powers and densely packed channel plan that minimizes the overall width of the channel plan that minimizes the overall width of the spectrum.spectrum.

Refractive Index PhenomenaRefractive Index Phenomena

This group of nonlinearities includes This group of nonlinearities includes - - self-phase modulation (SPM)self-phase modulation (SPM) - cross-phase modulation (CPM) - cross-phase modulation (CPM) - four-wave mixing (FWM) - four-wave mixing (FWM)

SPMSPM - This phenomena causes the signal's - This phenomena causes the signal's spectrum to spectrum to widen and can lead to crosstalk or widen and can lead to crosstalk or an unexpected an unexpected dispersion penalty. dispersion penalty.

Four-wave mixingFour-wave mixing - - results in cross-talk and signal-to-noise results in cross-talk and signal-to-noise degradation. degradation. - troublesome in the dispersion shifted fiber - troublesome in the dispersion shifted fiber that is used to propagate STM-64/OC-192. that is used to propagate STM-64/OC-192. - limit the channel capacity of a DWDM - limit the channel capacity of a DWDM system. system.

Market Scope and Company ProfileMarket Scope and Company ProfileKMI CorporationKMI Corporation

The DWDM systems market jumped from $4.2 billion in The DWDM systems market jumped from $4.2 billion in 1999 to $8.9 billion in 2000.1999 to $8.9 billion in 2000.From $1.7 billion in 1997, the market has grown at a From $1.7 billion in 1997, the market has grown at a 73% CAGR over the last four years.73% CAGR over the last four years.

This growth reflects several trends:This growth reflects several trends: - a maturation of the long distance segment of - a maturation of the long distance segment of the DWDM equipment market the DWDM equipment market - stiffening competition that will lead to price - stiffening competition that will lead to price pressures pressures

From 1999 to 2000From 1999 to 2000 - the number of vendors offering DWDM - the number of vendors offering DWDM system-level products grew from 15 to 30 system-level products grew from 15 to 30 - the number of carriers that have deployed - the number of carriers that have deployed DWDM climbed from 75 to 175. DWDM climbed from 75 to 175.

-- the number of contracts for DWDM will the number of contracts for DWDM will double from 75 to 150.double from 75 to 150. -- Such growth reflects the tremendous demand long-distance Such growth reflects the tremendous demand long-distance

carriers face for transport in bandwidth.carriers face for transport in bandwidth.Lucent Technologies - five-year agreement with Bell Atlantic valued Lucent Technologies - five-year agreement with Bell Atlantic valued

at approximately $500 million for optical networking, including at approximately $500 million for optical networking, including DWDM, network management software and SONET DWDM, network management software and SONET transmission equipment.transmission equipment.

According to Dell'Oro Group, Lucent captured the largest market share - 34 percent (or approximately $1.3 billion) - of the $3.8 billion global DWDM equipment market in 1999.Lucent will install the DWDM optical networking system in the new, 900- mile (1,300 km) route between Xian and Wuhan which is worth more than $10 million."Getting an early lead in this market will prove to be very important," said Scott Clavenna, principal analyst at Pioneer Consulting, which has forecast the metro DWDM market to grow to nearly $1 billion by 2003.

Future of DWDMFuture of DWDM

What the future holdsWhat the future holdsTwo-way video communication Two-way video communication Digital video for our everyday use at home and at work.Digital video for our everyday use at home and at work.Change from voice telephony to digital data heavy with video to Change from voice telephony to digital data heavy with video to require multiplying backbone transmission capacity.require multiplying backbone transmission capacity.The Ultimate SqueezeThe Ultimate Squeeze - reducing the “space” between wavelengths - reducing the “space” between wavelengths - expanding the range of transmission - expanding the range of transmission wavelengthswavelengths

- better EDFAs- better EDFAs

Develop better equipment for switching Develop better equipment for switching and manipulating the various wavelengths and manipulating the various wavelengths after the signal emerges from the optical after the signal emerges from the optical “pipe.”“pipe.”WDM is creating huge new information WDM is creating huge new information pipelines that will bring better service at pipelines that will bring better service at lower cost. But the real information lower cost. But the real information revolution won’t come until cheap WDM revolution won’t come until cheap WDM pipelines reach individual residences. pipelines reach individual residences.

Applications of DWDMApplications of DWDM

DWDM is ready made for long-distance DWDM is ready made for long-distance telecommunications operators that use either telecommunications operators that use either point-to-point or ring topologies. point-to-point or ring topologies. Building or expanding networks Building or expanding networks Network wholesalers can lease capacity, rather Network wholesalers can lease capacity, rather than entire fibers. than entire fibers. The transparency of DWDM systems to various The transparency of DWDM systems to various bit rates and protocols.bit rates and protocols.Utilize the existing thin fiber Utilize the existing thin fiber DWDM improves signal transmissionDWDM improves signal transmission

SummarySummary

Telco network growth was badly under estimatedTelco network growth was badly under estimatedDWDM was introduced to increase bandwidth by DWDM was introduced to increase bandwidth by better utilizing existing fiber optic cablingbetter utilizing existing fiber optic cablingDWDM is able to place many network formats of DWDM is able to place many network formats of different speeds on the same fiber optic cabledifferent speeds on the same fiber optic cableOptical Add-Drop Multiplexers and Cross Optical Add-Drop Multiplexers and Cross Connects are what places the digital signals on Connects are what places the digital signals on the fiberthe fiberLess cable and therefore less optical repeating Less cable and therefore less optical repeating equipment is needed for DWDM equipment is needed for DWDM DWDM SAVES $$$DWDM SAVES $$$

Thank You For Your Attention