(1) (
Wavelength
Division
Multiplexing) A communications technology that transmits several wavelengths of light (lambdas) simultaneously over a single optical fiber. Using multiple lasers, each signal travels within its unique color band modulated by the data.
WDM has dramatically increased the carrying capacity of the fiber infrastructure of the telephone companies and other carriers. Also known as "dense WDM" (DWDM), vendors have introduced systems that can support hundreds of wavelengths, each carrying 10 Gbps. That means terabits of data per second can travel over one optical strand, thinner than a human hair. Contrast with
TDM. See
CWDM and
fiber optics glossary. See also
FDM.
(2) (
Win32
Driver
Model) A device driver architecture from Microsoft that consolidates drivers for Windows 95/98 and subsequent versions of Windows. WDM allows a hardware vendor to write one driver for its peripheral device that works with all 32-bit versions of Windows. See
driver.