DWDM can be within the same root fibers, combining and transmitting different wavelengths simultaneously. To ensure a more effective, a fibre is conversion for multiple virtual fibre. So, if you intend to reuse 8 optical carrier (OC), consisting of a 8-channel signal transmission fiber, The transmission capacity will be increased from 2.5 GB/s to 20 Gb/s. At present, as a result of the DWDM technology, single root fibers can transmit data traffic up to 40Gb/s.
Wave min complex with (WDM) is two species or multiple different wavelength of light carrier signal (carrying various information) in sent end by complex with Manager (also said collection wave Manager, Multiplexer) convergence in together, and is coupled into light line of same root fiber for transmission of technology; in receives end, and The solutions complex with Manager (also said min wave Manager or said to complex with Manager, Demultiplexer) will be various wavelength of light carrier separation, then by light receiver made further processing to recovery original signal. This same root fiber is in the simultaneous transmission of two or many different wavelength optical signal technology, referred to as wavelength division multiplexing.
WDM is essentially frequency division multiplexed FDM technology in the optical domain. Segmentation of each wavelength channels by frequency-domain implementation, each wavelength channels using a fiber-optic bandwidth. Wavelength WDM system is different, that is, a specific standard wavelengths, wavelengths in order to distinguish them from ordinary SDH system, sometimes referred to as color optical interface, Or called ordinary optical interfaces of optical system for the "white light" or "white light".
Communications systems design, each wavelength width of an interval is different between. In accordance with the different channel interval, WDM can be subdivided into CWDM (rarefaction wave Division Multiplexing) and DWDM (dense wavelength division multiplexing). CWDM channel spacing is 20nm, and DWDM channel spacing from 0.2nm to 1.2nm, so relative to theDWDM,CWDM called rarefaction wave division multiplexing technology.