1[1].DWDM Introductionzx

7/29/2019 1[1].DWDM Introductionzx

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3/15/2013OFC Faculty DWDM Introduction

DWDM

INTRODUCTION


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FIBRE EXHAUST

2.5- Gbit/s

2.5- Gbit/s

2.5- Gbit/s

2.5- Gbit/s

transmitter

2.5-Gbit/s

2.5 Gbit/s

2.5 Gbit/s

reciever

Lay new fibre and install new systems

2.5 Gbit/s

2.5 Gbit/s

2.5 Gbit/s


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FIBRE EXHAUST

2.5- Gbit/s

2.5- Gbit/s

2.5- Gbit/s

2.5- Gbit/s

transmitter

2.5-Gbit/s

2.5 Gbit/s

2.5 Gbit/s

reciever

Install higher bit rate TDM Eqpt

Expensive, New fibre needed

10-Gbit/s 10-Gbit/s10-Gbit/s

transmitterregenerator reciever

2.5-Gbit/s


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FIBRE EXHAUST

DEPLOY DWDM2.5-Gbitt/s

transmitter

M

U

X

D

E

MU

X

2.5- Gbit/sreciever

2

1

3

4

2

1

3

4

2.5- Gbit/sreciever

2.5- Gbit/sreciever

2.5- Gbit/sreciever

2.5-Gbitt/s

transmitter

2.5-Gbitt/s

transmitter

2.5-Gbitt/s

transmitter

2.5- Gbit/s

2.5- Gbit/s

2.5- Gbit/s

2.5- Gbit/s

transmitter

2.5-Gbit/s

2.5 Gbit/s

2.5 Gbit/s

reciever

2.5 Gbit/s


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3/15/2013OFC Faculty DWDM Introduction 5

DWDM HISTORY

Early WDM (late 80s)

Two widely separated wavelengths (1310, 1550nm)

Second generation WDM (early 90s)

Two to eight channels in 1550 nm window

400+ GHz spacing

DWDM systems (mid 90s)

16 to 40 channels in 1550 nm window

100 to 200 GHz spacing

Next generation DWDM systems

64 to 160 channels in 1550 nm window

50 and 25 GHz spacing


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OVERVIEW

Now in use:

C-band 1525~1565nm

In research :

L-band 1570~1620nm

S-band 1400nm

In Future, the

communication window

1280~1625nm


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Friday, March 15, 2013OFC Faculty DWDM SYSTEM (ZTE MAKE)

ACHIEVING HIGHER BANDWIDTH

THREE POSSIBLE SOLUTIONS

INSTAL NEW FIBRE

INVEST IN NEW TDMTECHNOLOGIES TOACHIEVE HIGHER

BANDWIDTH. DEPLOY DWDM

EXPENSIVE

VERYEXPENSIVEREQUIRE NEWTYPE FIBRE

ECONOMICAL


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JUST LIKE WIDENING OF ROAD USING AVAILABE LAND TO MEET INCREASED TRAFFIC


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DWDM BASICS

SINGLE FIBRE

SDH OPTICAL SIGNALS

NEW REQUIREMENTS:


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BLOCK SCHEMATIC

Tx RxMUX DEMUX

OFAWD

M

W

D

M

2.

.

.

.

1

16

TRANSPONDERS

OPTICALSIGNALS.

STM-1STM-4STM-16

ATMIP


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WAYSIDE OPTICAL ADD/DROP

MULTIPLEXER

TM TMWDMMUX

WDMDEMUX

2

15

16

1

1-4 5-8

O

A

O

A


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OPTICAL ADD/DROP

MULTIPLEXING

1 12 2 2 2

Configurable

OADM :1 or 2

1 12 2 2 2

1 1

fixed OADM:

2

Terminal Equipt Terminal EquiptIn-Line Amplifier


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DIFFERENCES FROM OLD

SYSTEM

Regenerators

FIBRES REQUIREMENT

LASERS TYPES OF COMPONENTS

CAPACITY

FIBRE TRANSMISSION BEHAVIOUR


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ADVANTAGES OF DWDM


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TransparencyCan carry multiple protocols on same fiberMonitoring of multiple protocol is possible

Wavelength Spacing50GHz, 100GHz, 200GHzDefines how many and which wavelengths canbe used

Wavelength capacityExample: 2.5Gb/s, 10Gb/s

WAVELENGTH CHARACTERISTICS

OF WDM NETWORK


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WHY OPTICAL (DWDM)

NETWORKING?

Fibre Exhaust : Unlimited bandwidth on a fibre pair

Bit Rate Transparency

Format/Protocol Transparency : IP, ATM etc.

Efficient use and rearrangement of embedded opticalcapacity as per demand.

Minimal Capital Expenditure : Capacity Expansions

Demand.


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ECONOMICS OF WDM

Saving of regeneration costs:

One optical amplifier is required for regeneration of

multiple channels and thus cost per channel drastically

reduced. Saving of fibers is very cost effective incomparison to laying new fibers.


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OPTICAL NETWORK

ELEMENTS

TP

TP OAODEMU

X

OMUX

OADM OXC


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OPTICAL AMPLIFIER

Advantages:

Design simplicity & high reliability.

Fewer components and economical.

Very low noise level.

Ability to amplify multiple wavelength signals in the operating

band.

No inter-channel interference .

Careful design can remove the dispersion problems also.


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EDF Amplifier Characteristics :-

1. Highly Efficient

2. High gain

3. Low Noise figure.

4. Low Cost

ERBIUM DOPED FIBER

AMPLIFIER (EDFA)


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ERBIUM DOPED FIBER

AMPLIFIER

Simple device consisting of four parts:

Erbium-doped fiber An optical pump

A coupler

An isolator to cut off backpropagating noise

Isolator Coupler IsolatorCoupler

Erbium-DopedFiber (1050m)

PumpLaser

PumpLaser


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NMS FOR DWDM SYSTEMS

NMS in conventional SDH systems have

DCC: TIME SLOTS

DWDM :NO TIME SLOTS

Wavelength slots

One wavelength is dedicated for N.M.S.

Optical Supervisory Channel

OSC needs to be accessed at all points in the network


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OPTICAL SUPERVISORY

CHANNEL (OSC)

OSC mainly carries orderwire and network

management information.

signals at 1510 nm.

2.048 Mb/s


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OPTICAL SUPERVISORY

CHANNEL(OSC)

Line Terminal Equipment In-line Amplifier

Tx 1

Tx 2

Tx 3

Tx 4

Tx 5

Tx 6

Tx 7

Tx 8

DATAIN

1

2

3

4

5

6

7

8

Rx

Rx

Rx

Rx

Rx

Rx

Rx

Rx

DATAOUT

1

2

3

4

5

6

7

8

Line Terminal Equipment

+ supervisory

Tx sup

System ControlProcessor

Rx Tx

OSC

Network Management Network Management

System ControlProcessor

Rx sup


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OPTICAL BANDS

EXTENSIVE USE OF WAVELENGTH

Different vendors: Interoperability issues

Need for standard wavelength values

ITU Classification of bands

Standard values : ITU Grid

Center frequency: 193.10THz (1552.52 nm)

Standard spacing of 200, 100, 50 GHz for different applications


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ITU-T BAND ALLOCATION

OpticalSupervisorychannel

1500 1520 1530 1542 1547 1560 1620

REDBAND

C BAND L BAND

BLUE

BAND

C BAND products are commercially available.

ERBIUM DOPED FIBRE AMPLIFIERS is suitable for C BAND.

Gain in RED BAND is flattest for EDFA.

Some manufacturers provide 16 channels in RED BAND only. Others use both

RED & BLUE BANDS.


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1550.12193.41539.77194.8

1560.61192.11549.32193.51538.19194.9

1559.79192.21548.51193.61537.40195.0

1558.98192.31547.72193.71536.61195.1

1558.17192.41546.92193.81535.82195.2

1557.36192.51546.12193.91535.04195.3

1556.55192.61545.32194.01534.25195.4

1555.75192.71544.53194.11533.47195.5

1554.94192.81543.73194.21532.68195.6

1554.13192.91542.92194.31531.90195.71553.33193.01542.14194.41531.12195.8

1552.52193.11541.35194.51530.33195.9

1551.72193.21540.56194.61529.55196.0

1550.92193.31539.77194.71528.77196.1

Central

(nm)

NominalCentral

(THz)

Central

(nm)

NominalCentral

(THz)

Central

(nm)

NominalCentral

(THz)

ITUT G.692 FREQUENCY

GRID


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LIMITATIONS

The maximum distance is 640 km, made up of 8 SPANS of 80km

each

The assumptions are:

Fiber attenuation, including splice loss is 0.28 db/kmSpan loss of 22 db. (0.28 *80km =22.40 )

Total dispersion is less than 12800 ps/nm.

For G.652 fiber/ cable is DISPERSION 17/20 ps/nm-km

For 640 Km dispersion= 12800ps/nm

A CA O S


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Metropolitan Area Network

Unlimited Bandwidth, bit rate and format transparency

Efficient Bandwidth use and Management

NEW APPLICATIONS WITH

DWDM



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Wavelength Leasing Network Customers are beginning to demand high

capacity network Transport that can provide high

reliability and security

A spare Wavelength (Leased ) is used to provide

clear-channel transport to a customer .


DWDM


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3/15/2013ALT/TX-I/DWDM/SYS.ENG./06 31

OPTICAL PARAMETERS IN THE LINKENGINEERING

1. Topology description for our Network

DWDM: Point to Point

DWDM: Point to Multi Point

DWDM: Ring

SDH : Ring

Ultimately mesh with help of OXCs

2. With a mix of above, we will have to groomthe traffic to our need, in order to have trafficprotection against cable fault and equipmentfault


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TX-I ALTTC 29

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Documents

1[1].DWDM Introductionzx