FWDM
Wavelength Division Multiplexers or Demultiplexers (WDM) com- bine or separate optical signals with different wavelengths. They are passive optical components for uni- or bidirectional operation.
FWDM are multiplexer or demultiplexer which are used to com- bine or seperate signals with wavelength from neighbouring optical windows. They are used as band-pass filters for CWDM systems and instead of fused WDM modules if high isolation and small dimensions are required.