what is CWDM optical multiplexers Mux / Demux 8 + 1 Channel Module ?

Coarse Wavelength Division Multiplexing (CWDM) is a type of optical wavelength management device that are based on proven ultra low-loss thin-film filter (TFF) technology. It features small size, high reliability, high extensibility, simultaneous transmission of multi-wavelength.

CWDM has gained prevalence in multi-wavelength digital transport architectures because it enables the use of very low cost uncooled distributed feedback (DFB) laser transmitters. Moreover, their powering requirements are reduced and reliability is increased.