WDM Concept and Components

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Why WDM?

Capacity upgrade of existing fiber networks (without adding fibers)

Transparency: Each optical channel can carry any transmission format (different asynchronous bit rates, analog or digital)

Scalability– Buy and install equipment for additional demand as needed

Wavelength routing and switching: Wavelength is used as another dimension to time and space


WDM, CWDM and DWDM

WDM technology uses multiple wavelengths to transmit information over a single fiber

Coarse WDM (CWDM) has wider channel spacing (20 nm) – low cost

Dense WDM (DWDM) has dense channel spacing (0.8 nm) which allows

simultaneous transmission of 16+ wavelengths – high capacity

Key Components for WDM

Passive Optical Components
.Wavelength Selective Splitters
.Wavelength Selective Couplers
.Active Optical Components
Tunable Optical Filter
.Tunable Source
.Optical amplifier
.Add-drop Multiplexer and De-multiplexer