Reconfigurable Optical Add-drop Multiplexer (ROADM) - (Associated with Add/drop Multiplexing, Demultiplexer, WDM, OADM, MEMS, Wavelength-division Multiplexing, DWDM, Dense Wavelength-division Multiplexing, Wavelength Layer.) - A ROADM is a type of optical add-drop multiplexer. wikipedia.org/wiki/Reconfigurable_Add_Drop_Multiplexers