CWDM MUX DEMUX
The CWDM method multiplexes optical signals together on one single fiber. To achieve this it uses different colors (wavelengths) which are combined in a MUX. The device where the optical signals are multiplexed and de-multiplexed is called a MUX or a fiber optical multiplexer or a CWDM multiplexer.
All optical transmission is done by dual fibers where one fiber is transporting data from east to west and the other west to east. This dual function is possible because one MUX has both a multiplexer and a de-multiplexer. For CWDM this is 20nm (course) , CWDM has 18 wavelengths from 1270 to 1610 with steps of 20nm.
