Wednesday, November 5, 2008

3.1 Technologies for WAN and Backbone Networks - Optical Communication

Here is the overview of the presented content for ATM part.

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Optical Communications
Optical Communications and OSI
Advantages and Disadvantages
Different light source (LED and LASER)
Optical Fiber
Different Types of Fiber
Fiber Transmission Effects
Optical Attenuation
Optical Dispersion
Noise in Optical Transmission
Optical Networks (Operating wavelength)
SONET
Wave Division Multiplexing
Components
SONET Network
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Optical Communications (OC) is any form of communicatin using light. Its very high speed but harder to implement. In OSI, OC falls in the Physical layer and there are many ad and disad to using it.

Advantages
- more resistance to attenuation, noise. thus can transmit longer distant
- high speed
- better choice to use in dangerous environment like refinery
- Large BW permits aggregation of voice, video and data
- secure because difficult to tap

Disad
- difficult to install and handle
- cost

The two different light source for optical transmission are LED and LASER. No matter which light source is being used, they all suffer from a degree of attenuation, dispersion and noise. Where attenuation loss is due to absorption and signal scattering by fiber impurities and dispersion is the distortion of signal.

SONET - Synchronous optical networking is the multiplexing protocol for transferring multiple digital bit streams.

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