17-01-2012, 12:56 PM
WDM Concept and Components
[attachment=16161]
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