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DENSE WAVELENGTH DIVISION MULTIPLEXING

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Title: DENSE WAVELENGTH DIVISION MULTIPLEXING


1
DENSE WAVELENGTH DIVISION MULTIPLEXING
  • PRESENTED BY
  • PRITI RANI
  • MNW-891-2K11
  • MTECH(CN)
  • YMCAUST.FBD
  • PRESENTED TO
  • DR.SAPNA GAMBHIR
  • ASSOCIATE PROF.
  • CSE DEPTT.
  • YMCAUST.FBD.

2
CONTENTS
  • INTRODUCTION
  • VARIETIES OF WDM
  • DWDM TECHNOLOGY
  • HISTORY OF DWDM
  • DWDM SYSTEM AND COMPONENTS
  • TOPOLOGY

3
CONT
  • TRANSMISSION CHALLENGES
  • MARKET DYNAMIC
  • FUTURE
  • APPLICATIONS
  • BENEFITS
  • REFERNCES

4
INTRODUCTION
  • One of the major issues in the networking
    industry today is tremendous demand for more and
    more bandwidth.
  • With the development of Optical network and the
    use Dense Wavelength Division Technology, a new
    and probably, a very crucial milestone is being
    reached network evaluation.

5
OPTICAL NETWORKING
  • Optical networks are high-capacity
    telecommunications networks based on optical
    technologies.
  • The origin of optical networks is linked to
    Wavelength Division Multiplexing (WDM) which
    arose to provide additional capacity on existing
    fibers.


6
CLASSIFICATION OF OPTICAL NETWORK
  • FIRST GENERATION Networks use microwave
    technology based.
  • SECOND GENERATION Networks use microwave links
    with optical fibers.
  • THIRD GENERATION Networks employ
  • Wavelength Division Multiplexing technology.

7
What is DWDM?
  • Dense Wavelength Division Multiplexing (DWDM) is
    a fiber-optic transmission
  • technique.
  • It involves the process of multiplexing many
    different wavelength signals onto a single fiber.
    So each fiber has a set of parallel optical
    channels each using slightly different light
    wavelengths.

8
CONT..
  • It employs light wavelengths to transmit data
    parallel-by-bit or serial-by-character.
  • DWDM is a very crucial component of optical
    networks that will allow the transmission of
    data voice, video over the optical layer.

9
CONT..
  • It transmits multiple data signals using
    different wavelengths of light through a single
    fiber.
  • Incoming optical signals are assigned to specific
    frequencies within a designated frequency band.
  • The capacity of fiber is increased when these
    signals are multiplexed onto one fiber

10
CONT..
  • Transmission capabilities is 4-8 times of TDM
    Systems with the help of Erbium doped optical
    amplifier.
  • EDFAs increase the optical signal and dont
    have to regenerate signal to boost it strength.
  • It lengthens the distances of transmission to
    more than 300 km before regeneration .

11
Why DWDM?
  • Unlimited Transmission Capacity
  • Transparency
  • Scalability
  • Dynamic Provisioning

12
Is DWDM Flexible?
  • DWDM is a protocol and bit rate independent
    hence, data signals such as ATM, SONET and IP can
    be transmitted through same stream regardless
    their speed difference.
  • The signals are never terminated within the
    optical layer allows the independence of bit rate
    and protocols,allowing DWDM technology to be
    integrated with existing equipment in network.
  • Hence, theres a flexibility to expand capacity
    within any portion of their networks.

13
Is DWDM Expandable?
  • DWDM technology gives us the ability to expand
    out fiber network rapidly to meet growing demands
    of our customer, said Mike Flynn, group
    President for ALLTELs communications operations.
  • DWDM coupled with ATM simplifies the network,
    reduce network costs and provide new services.
  • They can add current and new TDM systems to their
    existing technology to create a system with
    virtually endless capacity expansion

14
DISADVANTAGES
  • Not cost effective for low channel numbers
  • Sonet/sdh network management system
  • Are not well equipped to handle dwdm topologies

15
DWDM SYSTEM
16
Comparison of TDM, WDM, and DWDM multiplexing
capabilities
Multiplex Scalable Protocol independent Bit rate independent Channels per optical fiber Optical system capacity Equivalent DS-3 connections
TDM No No No 1 2.5 Gbit/s 48
WDM Yes Yes Yes 2 5 Gbit/s 96
DWDM Yes Yes Yes 16 N/A at publication N/A at publication
17
EVOLUTION OF DWDM
18
A picture representing the really cool analogy
19
Example of Speeds
  • Currently Lucent DWDM systems support
    transmissions of 160 separate wavelengths. Each
    wavelength is capable of supporting a signal of
    up to 10 Gbps.
  • The total combined bandwidth is 1.6 trillion bits
    per second.
  • This is greater than the speed of one million T-1
    connections.

20
How DWDM saves
  • In addition to saving money on fiber cables, DWDM
    also saves money on optical repeating equipment
  • Because one fiber is used instead of many, one
    repeater can be used in place of many
  • For example you need 16 OC-3 carrier lines to go
    1000 miles and repeaters are needed every 100
    miles
  • If you didnt use DWDM, you would need 16
    thousand miles of fiber and 160 repeaters
  • With DWDM, you need only 1 thousand miles of
    fiber and 10 repeaters

21
A picture of How DWDM saves
  • Before DWDM

22
Signal Quality
  • Optical Signal to Noise Ratio
  • Optical Spectrum Analyzer

Optical Signal
Noise Floor
23
DWDM Components
  • Transmitter - Changes electrical bits to
    optical pulses
  • - Is frequency specific
  • - Uses a narrowband laser to generate the optical
    pulse
  • 5.2 Multiplexer/ Demultiplexer
  • - Combines/separates discrete wavelengths
  • 5.3 Amplifier
  • - Pre-amplifier boosts signal pulses at the
    receive side
  • - Post-amplifier boosts signal pulses at the
    transmit side
  • 5.4 Optical fiber (media)
  • - Transmission media to carry optical pulses
  • - Many different kinds of fiber are used
  • - Often deployed in sheaths of 144256 fibers

24
CONT
  • 5.5 Receiver (receive transponder)
  • - Changes optical pulses back to electrical bits
  • - Uses wideband laser to provide the optical pulse

25
DWDM Mesh Designs
26
(No Transcript)
27
Advantages of DWDM Point to Point Systems
  • The DWDM point-to-point architecture is simple
    to build and troubleshoot .
  • It enables protocol transparency, increme-ntal
    growth, and capacity expansion over time, while
    dramatically reducing start-up costs.
  • Point-to-point solutions are also extremely
    efficient.
  • No amplifiers or additional equipment required.

28
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

29
Rayleigh Scattering
30
CONT
  • 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.
  • These impurities absorb the optical energy,
    causing the light to become dimmer.

31
Absorption
32
Dispersion
  • Dispersion is the spreading of light pulses as
    they travel down optical fiber. Dispersion
    results in distortion of the signal, which limits
    the bandwidth of the fiber.
  • Two general types of dispersionChromatic
    Dispersion - is linear
  • Chromatic dispersion occurs because different
    wavelengths propagate at different speeds.
  • Increases as the square of the bit rate.
  • Polarization Mode Dispersion - is nonlinear.
  • Polarization mode dispersion (PMD) is caused by
    ovality of the fiber shape as a result of the
    manufacturing process or from external stressors.

33
CONT
  • Changes over time PMD is generally not a problem
    at speeds below OC-192.
  • Smearing of the signal
  • Fiber Non Linear ties
  • Because nonlinear effects tend to manifest
    themselves when optical power is very high, they
    become important in DWDM.
  • These nonlinearities fall into two broad
    groups
  • - scattering phenomena
  • - refractive index phenomena

34
Future of DWDM
  • What the future holds
  • Two-way video communication
  • Digital video for our everyday use at home and at
    work.
  • Change from voice telephony to digital data heavy
    with video to require multiplying backbone
    transmission capacity.
  • The Ultimate Squeeze - reducing the
    space between wavelengths - expanding
    the range of transmission wavelengths
  • - better EDFAs

35
  • Develop better equipment for switching and
    manipulating the various wavelengths after the
    signal emerges from the optical pipe.
  • WDM is creating huge new information pipelines
    that will bring better service at lower cost. But
    the real information revolution wont come until
    cheap WDM pipelines reach individual residences.

36
Applications of DWDM
  • DWDM is ready made for long-distance
    telecommunications operators that use either
    point-to-point or ring topologies.
  • Building or expanding networks
  • Network wholesalers can lease capacity, rather
    than entire fibers.
  • The transparency of DWDM systems to various bit
    rates and protocols.
  • Utilize the existing thin fiber
  • DWDM improves signal transmission

37
Summary
  • DWDM was introduced to increase bandwidth by
    better utilizing existing fiber optic cabling
  • DWDM is able to place many network formats of
    different speeds on the same fiber optic cable
  • Optical Add-Drop Multiplexers and Cross Connects
    are what places the digital signals on the fiber
  • Less cable and therefore less optical repeating
    equipment is needed for DWDM
  • DWDM SAVES

38
THANKYOU FOR YOUR ATTENTION
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