DWDM MUX/DEMUX have different types.
1.Classification by manufacturing teachnology,
TFF DWDM，Thin Film Filter WDM,use filter to make,general its insertion loss from low to high in Mux part,from high to low in Demux part,so this type DWDM generally use as a pair(Mux with Demux as a pair),this can be sure the insertion loss is similar(same wavelength line).
Arrayed Waveguide Grating,i.e. AWG,it is made by one whole chip,its insertion loss is similar in each output port,so actually must not class MUX and DEMUX.The parts of Mux and DEMUX are the same.
2.Classification by transmission rate and wavelengths,
There’re 50Ghz DWDM,100Ghz DWDM,150Ghz DWDM,C band DWDM and O band DWDM and so on.
