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Dense wavelength division multiplexing (DWDM)

Definition
Dense wavelength division multiplexing (DWDM) is a fiber-optic
transmission technique that employs light wavelengths to transmit data
parallel-by-bit or serial-by-character.
Overview
The role of scalable DWDM systems in enabling service providers to
accommodate consumer demand for ever-increasing amounts of
bandwidth is important. DWDM is discussed as a crucial component of
optical networks that allows the transmission of e-mail, video,
multimedia, data, and voice—carried in Internet protocol (IP),
asynchronous transfer mode (ATM), and synchronous optical
network/synchronous digital hierarchy (SONET/SDH), respectively,
over the optical layer.