WDM is a simple technique. It allows secured transmission of optical signal. This technique increases the signal carrying capacity of the system.

High Capacity
An important feature of WDM is that it can make full use of the bandwidth resources of optical fibers, increase the data transmission capacity without changing the basic structure of the existing network, and increase the transmission capacity of an optical fiber many times compared with that of a single wavelength. For example, a DWDM system can support up to 192 wavelengths in a pair of optical fibers, and the transmission capacity of each wavelength is as high as 100Gbit/s ~ about 400Gbit/s and one Terabit/s.

Good Compatibility
WDM has good compatibility with different signals. When transmitting signals of different natures such as images, data and voice in the same optical fiber, each wavelength is independent of each other and does not interfere with each other, ensuring the transparency of transmission.

High Network Flexibility, Economy & Reliability
WDM technology allows for easier upgrades by allowing new channels to be connected as needed without disrupting existing traffic service. When upgrading and expanding the network, there is no need to modify the optical cable line, and new services can be opened or superimposed by adding wavelengths, saving a lot of optical fibers and 3R regenerators during long-distance transmission with large capacity, and the transmission cost is significantly reduced.

Wavelength Routing
WDM technology is one of the key technologies to realize all-optical network. In the all-optical network that is expected to be realized in the future, by changing and adjusting the wavelength of the optical signal on the optical path, the up/down and cross-connection of various telecommunication services can be realized.

What is Multiplexing Mux and Demultiplexing Demux?

Multiplexer MUX
The main function of the multiplexer MUX is to combine multiple signal wavelengths into one optical fiber for transmission. At the sending end, N optical transmitters work on N different wavelengths, and the N wavelengths are separated by appropriate intervals, which are respectively recorded as λ1, λ2...λn. These N light waves, as carriers, are respectively modulated by signals to carry signals. A multiplexer combines these optical carrier signals of different wavelengths and couples them into single-mode fiber. Since the optical carrier signals of different wavelengths can be regarded as independent of each other (without considering the nonlinearity of the optical fiber), the multiplexing transmission of multiple optical signals can be realized in one optical fiber. Through multiplexing, communication operators can avoid maintaining multiple lines, effectively saving operating costs.

Demultiplexer DEMUX
The main function of the demultiplexer DEMUX is to separate multiple wavelength signals transmitted in one optical fiber. In the receiving part, the optical carrier signals of different wavelengths are separated by a demultiplexer, and further processed by the optical receiver to restore the original signal. A multiplexer (Demux) is a device that performs reverse processing on a multiplexer.

In principle, the device is reciprocal (two-way reversible), that is, as long as the output and input of the demultiplexer are used in reverse, it is a multiplexer.