E3-E4 (E&WS)
DWDM & OXC
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AGENDA
The Challenges of Today's
Telecommunications Network
Resolving the Capacity Crisis
Capacity Expansion and Flexibility
Capacity Expansion Potential
Optical Layer as the Unifying Layer
Optical Cross Connect
MEMS
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DWDM
Definition
Dense wavelength division multiplexing (DWDM)
is a fiber-optic transmission technique that
employs multiple light wavelengths to transmit
data in parallel through a single fiber.
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BLOCK SCHEMATIC
Tx RxMUX DEMUX
OFA W
D
M
W
D
M
λ2
.
.
.
.
λ1
λ16
TRANSPONDERS
OPTICALSIGNALS.
STM-1STM-4STM-16
ATMIP
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CHALLENGES OF TODAY'S
TELECOMMUNICATIONS NETWORK
The forecasts of the amount of bandwidth
capacity needed for networks were calculated
on the presumption
Challenge of deploying and integrating diverse
technologies in one physical infrastructure.
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CHALLENGES OF TODAY'S
TELECOMMUNICATIONS NETWORK
DWDM provides unique bandwidth management
capabilities by offering services such as e-mail,
video, and multimedia carried as IP data over
ATM and voice carried over SDH.
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RESOLVING THE CAPACITY CRISIS
Challenges of increased bandwidth needs as
well as of laying new fiber after fiber exhaust.
By increasing the bit rate using time division
multiplexing (TDM), service providers purchase
more capacity than they initially need and it may
remain unutilized in the near future.
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CAPACITY EXPANSION AND
FLEXIBILITY
By combining multiple optical signals and
transporting over a single fiber of different rate
and of different format (SDH, ATM, data, etc.)
i.e. DWDM can carry 80 wavelengths, each of
STM-16 capacity i.e. total of 200 Gbps.
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CAPACITY EXPANSION AND
FLEXIBILITY
High-speed, high-volume transmission is
possible through deployment of optical amplifier.
Optical amplifiers operate in a specific band of
the frequency spectrum while ultra wideband
optical-fiber amplifiers can boost light wave
signals carrying over 100 channels (or
wavelengths) of light.
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CAPACITY EXPANSION POTENTIAL
Flexibility to expand capacity in networks.
Compared with repeater-based applications it
increases the distances between nodes.
Using fewer regenerators in long-distance
networks results in fewer interruptions and
improved efficiency.
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OPTICAL LAYER AS THE
UNIFYING LAYER
Optical layer integrates the diverse technologies
of their existing networks into one physical
infrastructure
DWDM is Bit-rate and format independent and
can accept any combination of interface rates
Optical layer carries signals without any
additional multiplexing, i.e. ATM or IP without
deploying an overlay network
DWDM SYSTEM
CHARACTERISTICS
Well-engineered DWDM systems offer
component reliability, system availability, and
system margin.
Automatic adjustment of the optical amplifiers
when channels are added or removed ensures
optimal system performance.
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DWDM SYSTEM
CHARACTERISTICS
In the 1530- to 1565-nm range, silica-based optical
amplifiers with filters and fluoride-based optical
amplifiers perform equally well. However, fluoride-
based optical amplifiers are intrinsically more costly
to implement
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WHY OPTICAL (DWDM)
NETWORKING
Fibre Exhaust : Tapping the unlimited bandwidth
on a fibre pair
Bit Rate Transparency
Format/Protocol Transparency : IP, ATM etc
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ECONOMICS OF DWDM
Saving of regeneration costs by multiplexing
multiple wavelengths on a single fiber, can
decrease the number of amplifiers by a huge
factor at each regenerator site.
Cost effective compared to laying new fibers
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EDFA
Erbium Doped Fiber Amplifier (EDFA)
Optical fiber that is doped with the element
erbium and the amplifier. When a pump laser is
used to energize the erbium with light at a
specific wavelength, the erbium acts as a gain
medium that amplifies the in coming optical
signal.
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OPTICAL CROSS CONNECT
Optical cross connects (OXC):Light in one fiber can be
moved into a different fiber i.e. redirecting the light.
An optical cross-connects (OXCs) is also referred to
as a wavelength cross-connect (WXC) or a
wavelength router. It is an optical device that can route
an input wavelength on an input port to an output port.
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MICRO-ELECTRO-MECHANICAL
SYSTEMS (MEMS)
MEMS consist tiny moveable mirrors no larger in
diameter than a human hair. They can be
arranged on special pivots so that they can be
moved in three dimensions, and several
hundred such mirrors can be placed together on
mirror arrays no larger than a few centimeters
square
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MEMS Mirror
MEMS Optical Cross Connect
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MEMS OPTICAL CROSS
CONNECT
Light from an input fiber is put at a mirror, which
is directed to move the light to another mirror on
a facing array. This mirror then reflects the light
down towards the desired output optical fiber.
Most advanced optical switching technology is
MEMS, with tiny moveable mirrors
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SUMMARY
Cross connects forward signals to their destination
by specific routes
Traditional cross connects convert light to
electricity then back to light
OXC has many advantages including less cost,
smaller size, and bit-rate transparency as it
redirects the light from one optical fiber to another,
without electrical conversion
THANKS
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