WHAT IS DWDM? WHERE IS IT USED, WHAT ADVANTAGES DOES IT OFFER?

DWDM is an abbreviation consisting of the initials of the words (Dense Wavelength Division Multiplexing). In Turkish, it stands for Dense Wavelength Division Multiplexing.

DWDM is generally used to transport multiple pieces of information over a single fiber optic cable (single hair) without affecting each other. In practice, the bandwidth of the fiber optic cable can be considered unlimited. Even the highest speeds we are currently using (1 Gbps, 10 Gbps, 100 Gbps) use a very small fraction of the bandwidth of the fiber optic cable. Using the existing cable to transmit more information is especially important where fiber optic cable investment is very expensive. For example, it is very expensive to run additional cable in an undersea fiber cable. Or in a metropolis like Istanbul, it is not easy to dig every day and get permission to lay new cables.

DWDM systems transmit different information using carriers that use different wavelengths. Since each signal is transmitted over a different wavelength, it does not affect other information transmitted over the same cable.

To understand how the DWDM system works, we can use the example of FM radio. More than one radio is broadcasting from Çamlıca hill and dozens of cars on the road are listening to the radio. When everyone tunes in to the radio frequency they want to listen to, they only listen to that frequency. The radio uses filters to filter out signals from other frequencies to prevent them from affecting the radio you are listening to.

In the DWDM system, each signal is transmitted with a carrier at a different frequency (wavelength is 300,000,000/frequency). Multiple receivers receive only signals locked to their own frequency. Different wavelength also means different color. Like only red, only yellow or only blue.
In addition to transmitting the same amount of information over the cable, WDM systems are also used to build a fiber ring and offer different services over this ring.

As people’s communication needs increase, WDM systems will grow in popularity.