DWDM (Dense Wavelength Division Multiplexing) is the technique that enable more than one wavelength to be added to a single-mode fiber, thus increasing the capacity of that transmission path by a factor equal to the number of wavelengths added. As the telecommunication carriers are challenged with requirement for a dramatic increase in network capacity.System currently exist that support 160 wavelength per fiber.

DWDM Hardware

DWDM multiplexer/demultiplexer: Combines multiple optical signals into a single optical fiber and separates optical signals. Stated differently, it separates optical wavelengths into a single wavelength per fiber.

Optical add/drop multiplexer (OADM): Acts like a SADM, except that it functions exclusively in the optical domain. It allows wavelengths to be split or added to a DWDM fiber.

OXC: Acts as a cross-connect between n-input ports and m-output ports. It provides efficient network management of wavelengths at the optical layer. The functions that can be performed are signal monitoring, restoration, provisioning, and grooming.

Optical amplifier: Amplifies the optical signals so that the signaling strength can travel over long distances.

Regenerator: Provides the functionality of an optical amplifier with re-sharing and re-timing capabilities.