Definitions by Hillarion of Sudbury

DWDM 

Dense wavelength division multiplexing (Wikipedia). Basically, a scheme for carrying oodles of channels via optical fibers; one fiber carries many different "colors" (wavelengths) of infrared light, and each "color" is a separate communications channel. See Wikipedia
wavelength division multiplexing for more info., including Coarse WDM.

DWDM -- See the Wikipedia article. Not found in homes, and won't be, for some time, most likely.

DWDM by Hillarion of Sudbury June 7, 2011