WDM Solutions - MRV Communications - #2

Gigabit Ethernet

Wavelength Division Multiplexing (WDM) is a method of transmitting data from different sources over the same fiber optic link at the same time whereby each data channel is carried on its own unique wavelength. The result is a link with an aggregate bandwidth that increases with the number of wavelengths employed. In this way WDM technology can maximize the use of the fiber optic infrastructure that is available; what would normally require two or more fiber links instead requires only one.

CWDM vs. DWD

There are two types of WDM implementations: Dense Wave Division Multiplexing (DWDM) and Coarse Wave Division Multiplexing (CWDM). DWDM systems utilize temperature-stabilized lasers and narrow band filters to achieve narrow channel spacing of 0.8 nm or less, enabling the transmission of 16 or more wavelengths/data channels within a given color spectrum. CWDM systems in comparison use non-stabilized lasers along with broadband filters for wider channel spacing of 20 nm, allowing for up to 16 transmitted wavelengths.

In general, DWDM is the best choice for applications where channel density/bandwidth is of high priority. At the same time, CWDM remains an excellent option for applications where deployment costs are to be considered.