WDM system uses a multiplexer at the transmitter to join the signals together, and a demultiplexer at the receiver to split them apart. With the right type of fiber it is possible to have a device that does both simultaneously, and can function as an optical add-drop multiplexer. The optical filtering devices used have traditionally been etalons, stable solid-state single-frequency Fabry-Perot interferometers in the form of thin-film-coated optical glass.

DWDM and CWDM both use WDM technology to arrange several fiber optic lights to transmit simultaneously via the same single fiber optic cable, but DWDM carry more fiber channel compared with CWDM (Coarse WDM). CWDM uses the 1300nm and 1550nm wavelength for full duplex transmission, that is to say, if a signal is sent in one direction by 1300nm, it can be sent back by 1550nm via the same optical fiber. DWDM is the multiplexing of 4, 8, 16, 32 or more wavelengths in the range of 1530nm to 1610nm range with a very narrow separation between the wavelengths.

--CWDM include CWDM mux/demux module and CWDM OADM module. The common configuration of CWDM mux/demux module is 2CH, 4CH, 8CH, 16CH, 18CH CWDM mux/demux module. Single fiber or dual fiber connection for CWDM Mux/demux are available.
--DWDM include 50GHz, 100GHz, 200GHz DWDM mux/demux module and DWDM OADM module. The common configuration is 2CH, 4CH, 8CH, 16 CH, 32CH, 40CH channels.

Thanks to DWDM technology, a single optical fiber capacity nowadays could reach 400Gb/s, and this capacity may even enlarge with more channels are added in DWDM. A critical advantage of DWDM is its protocol is not related to its transmission speed, thus IP, ATM, SONET/SDH, Ethernet, these protocols could be used and transmission speed between 100Mb/s to 2.5Gb/s. DWDM could transmit different type of data at different speed on the same channel. DWDM is usually used on fiber optic backbones and long distance data transmission and DWDM system has higher demand of fiber amplifiers.

By using WDM and optical amplifiers, people can accommodate several generations of technology development in their optical infrastructure without having to overhaul the backbone network. Capacity of a given link can be expanded by simply upgrading the multiplexers and demultiplexers at each end.

High density options - both 40 and 96 channel mux/demux solutions can provide an ideal solution for high density, add/drop requirements in DWDM networks, providing easy access of up to 96 wavelengths at a single site.

FiberStore offers a wide array of WDM networks, to efficiently and cost effectively multiply the capacity of existing fiber infrastructures and scale networks. FiberStore's multiplexing elements can achieve a full add/drop of up to 96 DWDM channels and/or 16 CWDM channels. Among them the 8 channel CWDM and 18 channel CWDM multiplexer are the hottest ones.