This is often done by the use of optical-to-electrical-to-optical (O/E/O) translation at the very edge of the transport network, thus permitting interoperation with existing equipment with optical interfaces.OverviewIn, wavelength-division multiplexing (WDM) is a technology which a number of signals onto a single by using different (i.e., colors) of. A WDM system uses a at the to join the several signals together and a at the to split them apart. With the right type of fiber, it is possible to have a device that does both s.