DWDM Complete

7/30/2019 DWDM Complete

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DENSE WAVE DIVISION

MULTIPLEXING


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OPTICAL MULTIPLEXERS

SINGLE FIBER

Wavelength MultiplexingMULTIPLE FIBER


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Wave Length Multiplexing

Multiplexing multiple wavelengths over asingle fiber

Two Major TypesCWDM Coarse Wave Length Division Multiplexing

Channel Spacing 20 nanometers

DWDM Dense Wave Length Division Multiplexing

Channel Spacing 8 nanometers


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WDM Categories

Wrapperless SystemsProtocol Independent

Wrapper Systems

Framed optical channel

Various low-level transmission functions

Error checking

Performance monitoring

Forward Error Correction (FEC)

Management channel to support OAM&P

Optical bitstream interpretable by higher-level

protocols


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New Service Offerings


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Emerging Scenario


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TDM Vs WDM


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TDM Vs WDM


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The Shrinking ContinentThe Shrinking Continent

1993

LA NY

2.5 Gb/s/fiber pair 40km between regenerators $20,000 per DS1 (excluding fiber costs)

OC-48

. . .

1998

LA NY

100 Gb/s/fiber pair 400km between regenerators $1,000 per DS1 (excluding fiber costs)

100Gb/s with DWDM

. . .

40x Increase

in bandwidth

Technology is conquering distanceTechnology is conquering distance

10x Increase

in regen spacing

20x decreased

in cost

Advantage - DWDM


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DWDM Evolution


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WAVELENGTH WINDOWS


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ITU-T WAVELENGTH GRID


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Frequency Utilization for Fiber Application

Window Label Range(nm) Fiber type Applications

First -- 820-900 MF LAN-Type

Second S 1280-1350 SMF Single-Third C 1530-1565 NZDSF DWDM1

Fourth L 1565-1620 NZDSF

Fifth -- 1350-1450 SMF AllwaveTM DWDM

Fifth -- 1450-1528 NZDSF

DWDM/MAN2

1DWDM may also include single wavelength application2 Currently, EDFAs do not perform below the range of 1530 nm.


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WAVELENGTH MULTIPLEXING


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Wavelength Multiplexing


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Multiple Lambdas

Delhi

Bombay

Cal

Chennai

NagpurX-Connect


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Optical Amplifier


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OPTICAL ADD-DROP MULTIPLEXERS


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Drop-ADD Wavelength N

1, 2,.., N

OA OA

OADM

1, 2,.., N1, 2,.., N

N N

Fiber Fiber


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Optical Switch

Fiber Fiber

1, 2,.., N 1, 2,.., N

Optical

DemultiplexerOptical

Multiplexer

1 1

Optical 2 X 2 Switch

Drop-Add wavelength 1


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A Typical DWDM Link

Channel 2

Channel 1

Channel N

1

2

N

Opt.MUX

OA OA

Fiber

Opt.De-MUX

1, 2,.., N 1, 2,.., N

OADM

1

2

N

= Laser Diode

= Receiver


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HUB

OADM

OADM

OADM

STM

DWDM Ring Network

IP

1, 2,.., N

1, 2,.., N 1, 2,.., N

1, 2,.., N

O/E

IP

STM

j j

k k


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DWDM Application

O/ETCP/IP

O/EATM

O/ESTM

PLL

OPT.

Demux

1, 2,.., N

Single-Mode Fiber

Detectors

PHY

TCP/IP

ATM

STM

Electronic Regime Photonic Regime

Receive Direction


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DWDM RING - Example


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Optical Transmission Problems

AttenuationLight Absorption

Raleigh Scattering

Bending Losses

Dispersion

Chromatic Dispersion

Polarization Mode Dispersion (PMD)


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Non-Linearity

Generation of spurious harmonic and sumfrequencies

Unexpected loss effects

Inherent characteristic of electromagnetic

energy passing through a physical medium

Effects

Scattering

Refractive Index Phenomena


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Non Linearity Effects

Scattering PhenomenaStimulated Brillouin Backscattering

Stimulated Raman Scattering

Refractive Index Phenomena

Self phase modulation

Cross phase modulation

Four-wave mixing


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Network Classification

Single-Hop Networks Data stream travels from source to destination as a light stream

No conversion at any of the intermediate nodes

Types

1. Broadcast-And-Select Networks

Star topology with passive star coupler device

Used in LAN/MAN

2. Wavelength Routed Networks

Wavelength selective switching sub-system

a. Wavelength Path Switching

Dynamic signal switching from one path to anotherb. Wavelength Conversion

Reuse of same wavelength in different parts of the same network(different fibers)

Multi-Hop Networks Small no of wavelength channels employed by the network


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FIBEROPTICS - Basics


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Journey through the Optical Tunnel


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TOTAL INTERNAL REFLECTION

Snells Law: n1*sin1 = n2*sin 2


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Transmit-Receive Overview


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Transmitter - fundamentals of emission


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Source composition


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Light Source comparison


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Transmitter & Receiver Functions


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Transmitter Simple Block Diagram


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Transmitter Basic Specifications


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Laser/ LED Drivers


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LASER Temperature Compensation


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Receiver Basic Specifications


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Receiver Block Diagram


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Dense Wave Division Multiplexing

DWDM

Standard support 1000 colors of light, only 160 colors

supported today

Key players - Ciena, Cerent (Cisco), Lucent, Marconi, Nortel,

Siemens, Sycamore

Supports PoS packet over Sonet to Wavelength Supports LAMBDA routing

Attenuation

Wavelength 1.3 1.4 1.5 1.6(mm)

1.0 dB/KM

0.3


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What is an Optical Wave?

An optical wave is a transponder-based service

which provides unprotected, customized bandwidthprimarily for data traffic and allows data carriers

requiring low restoration rates to provide protection

switching using their own equipment.Wave 1

Wave 2

Wave 3

Wave 4

Wave 1

Wave 2

Wave 3

Wave 4


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Customized Bandwidth

OC-48STM16

OC-3/STM1

OC-12/STM4OC-24/STM8

OC-N

Delhi

Bombay

Cal

Chennai

NagpurX-Connect


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Propagation mode


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Single Mode Fiber


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Number of Modes:

M = V2/2

Multi Mode Fiber


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Graded Index Fiber


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Propagation in Graded Index Fiber

Number of Modes, M = (a/(a+2))*(v2/2)

where a is Profile parameter


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Energy Distribution in SM Fiber


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Attenuation in Optical Fiber


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Power expressed in dbmIts simple to relate to attenuation if Power is also expressed in terms of db.

So if mW is the reference: Power in dbm = 10log10(P/mW)

Where mW is the reference: Power in dbm = 10log10(P/mW)


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DispersionBW Losses


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Dispersions in MM & SM Fiber


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Dispersion in Step Indexed Fiber


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Graded Index Fiber less dispersion


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LED: Typical spectral width 75-125 nm LASER: Typical spectral width 2-5 nm

Chromatic Dispersion


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Material Dispersion


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Wave guide Dispersion


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Polarization


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Bending Losses

Date post:	14-Apr-2018
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DWDM Complete

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