CWDM Mux / Demux (Coarse Wavelength Division Multiplexing) is a low-cost WDM transmission technology for the metropolitan area network access layer. CWD mux demux fiber can increase network capacity by transmitting multiple data channels with separate optical wavelengths (1270nm to 1610nm) on the same single fiber.There are many fiber optic cable vendors, but we are one of the best choices for you.