Wavelength division multiplexing (WDM) can help network operators stay ahead of growing demand for bandwidth. Read on to learn the fundamentals of this useful technology.
Question 1: What does it do?
In traditional fiber-based telecommunications, information is transmitted over dedicated fiber links using laser light sources. Light sources are based on common wide optical spectrum bands and are often referred to as ‘grey’ optics.
As the number of services and data rates increase for a link, a service provider has the choice to either add more fiber, or to use wavelength division multiplexing. WDM increases the capacity of a given fiber link by using light sources of specific narrow band spectrum or wavelengths for multiple services. These sources (transceivers) are often referred to as ‘colored’ optics.
By using the same fiber link for multiple service streams, savings can be realized vs. constructing or leasing new fiber paths.
Question 2. What exactly is the technology itself?
Multiple traffic channels can be assigned different wavelengths and then multiplexed (mixed) onto a fiber link with WDM filter devices. On the other end of the network, WDM filters will demultiplex (separate) the signals for the respective channels.
There are different filtering technologies such as thin film filters or arrayed waveguides, but their function is the same. WDM Multiplexers and Demultiplexers combine and separate different wavelengths (colors) of light signals on a common fiber connection. This technology can significantly increase the capacity of limited fiber resources.
Question 3. What are the benefits of WDM?
A major concern in today’s connected world is fiber exhaust, where the demands for fiber exceed the amount of available fiber in the network. The evolution of WDM technology can alleviate fiber exhaust, by requiring fewer fibers to transmit and receive multiple services.
By utilizing more wavelengths, the potential bandwidth capacity of a single fiber strand grows. Both wireless and wireline networks use WDM. From long haul to metro and local access networks, including FTTH, mobile backhaul and front haul. As these networks continue to converge, there is even more value to utilizing WDM.
