DWDM Optical Add/Drop Multiplexer (OADM)

OADM is a passive optical device used in WDM networks for adding and dropping one/multiple 100 GHz DWDM channels in the C-band into one or two fibers, while letting the rest of the wavelengths bypass to the needed destination. Using the DWDM technology can add effectively WDM capability to their existing and new networks, and extend the optical signals transmission distance.

For example.