A PRESENTATION ONDWDM (Dense wavelength

Division multiplexing)

MADE BY :-SHUCHISHMAN BURMAN090103508ECE-D

IntroductionMultiplexing

a process where multiple analog message signals or digital data streams are combined into one signal over a shared medium

TypesTime division multiplexingFrequency division multiplexing

OpticallyTime division multiplexingWavelength division multiplexing

WAVELENGTH DIVISION MULTIPLEXING :

•WDM is a technology which multiplexes multiple optical carrier signals on a single optical fiber by using different wavelengths of laser light to carry different signals.

• There are two types of WDM— > Coarse WDM > Dense WDM

Evolution of DWDM

Late 1990’s

1996DWDM

Early1990’s

Narrowband WDM

1980’sWideband WDM

16+ channels 100~200 GHz

spacing2~8 channels200~400 GHz

spacing

2 channels1310nm, 1550nm

64+ channels25~50 GHz spacing

Dense wavelength division multiplexing (DWDM) is a fibre-optic transmission technique that employs light wavelengths to transmit data parallel-by-bit or serial-by-character.

dense wavelength division multiplexing

(dwdm)

BLOCK DIAGRAM OF DWDM SYSTEM

The following steps describe the system :-

1. The transponder accepts input in the form of standard single mode laser. The input can come from different physical media and different protocols and traffics types.

2. The wavelength of each input signal is mapped to a DWDM wave length.

3. DWDM wave length from the transponders are multiplexed into single optical signal and launched into fiber

4. A post amplifier boosts the strength of the optical signal as it leaves the system

5. Optical amplifier are used along the fiber span as needed

6. A pre amplifier boosts the signal before it enter the end system

7. The incoming signal is de multiplexed and fed to respective receiver

8. From receiver they are transmitted to different system according to requirement

OVERVIEW OF DWDM NETWORK ARCHITECTURE

Optical Transponder Unit (OTU):

The major function of the OTU board is to employ the

Optical /electrical/ optical conversion made to realize wave

length conversion. OTU includes transmission OTU and

receiver OTU.

Optical Multiplexers and De-multiplexers Unit (OMU & ODU):-As DWDM system send signal from several source over a single fiber, they must include some means to combine the incoming signal. This is done with multiplexers, which take optical wavelength from multiple fiber and converge them into one beam

Multiplexing & Demultiplexing using Prism and Lens

De multiplexing Using Array of Wave GuideOptical Add Drop Multiplexers (OADM):

This is the area in which multiple wave length exist .It is often desirable to be able to remove or insert one or more wavelength at some point along this spans. An OADM performs this function. Rather than combining and separating all wave length, the OADM can remove some while passing others.

Optical Fiber Amplifier (OBA, OLA, OPA):Optical amplifiers also can be used to boost signal power after multiplexing or before de multiplexing By making it possible to carry large loads that DWDM is capable of transmitting over long distance, the EDFA (Erbium Doped Fiber Amplifier) was key enabling technology

Optical Supervisory Channel (OSC):It is used for supervision of DWDM networks and its

components. It works on wave length of 1510 nm and speed of 2.048 Mb/s .It is use in Network Monitoring System.

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OPTICAL BANDSEXTENSIVE USE OF WAVELENGTHS

DIFFERENT VENDORS:INTEROPERABILITY ISSUESNEED FOR STANDARD WAVELENGTH VALUES

ITU Classification of bandsStandard 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

Optical Supervisorychannel

1500 1520 1530 1542 1547 1560 1620

REDBAND

C BAND L BAND

BLUE

BAND

• C BAND PRODUCTS ARE COMMERCIALLY AVAILABLE.

• ERBIUM DOPED FIBRE AMPLIFIERS SUITABLE FOR ‘C’ BAND.• GAIN IN RED BAND FLATTEST FOR EDFA.• SOME MANUFACTURERS PROVIDE 16 CHANNELS IN RED BAND ONLY. OTHERS USE BOTH RED & BLUE BANDS.

BENEFITS OF DWDM ::

• Capacity increase : Large aggregate transmission capacity.

• Upgradability : Customer growth without requiring additional fiber to be laid.

• Flexibility : Optical Add/Drop Multiplexing (OADM) Optical Cross connect (OXC)

• Scalability : The possibility to add new nodes to the network.

• Network Transparency : Independence of data rate, format & protocols.

ADVANTAGES OF DWDM

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LIMITATIONS

• DWDM TRANSMISSION IS ANALOG. THE IN LINE AMPLIFIERS ARE ALSO ANALOG.

THIS IMPLIES THAT THE SIGNAL TO NOISE RATIO WORSENS WITH DISTANCE.

• FIBRE DISPERSION IS ANOTHER LIMITATION.