The best thing about an optical communication link is that you can transmit signals of varying wavelengths along the single fiber at the same time. There is no need to lay different cables or fibers and no need to worry about spending on the labor for laying those fibers. The technology that allows you to combine different wavelengths onto the same fiber is known as wavelength-division multiplexing (WDM).

fused wdm

In this blog, we will talk about the key features of WDM and the operational principles of this technology.

Key Features of Wavelength Division Multiplexing

Here are some of the salient features of WDM systems:

  • Increased Capacity: WDM is exclusively meant to multiply the capacity of a fiber network cost-effectively.
  • Better Compatibility: Another good thing about WDM technology is that each optical channel supports all transmission formats.
  • Wavelength Routing: The implementation of wavelength-sensitive optical routing devices makes it possible for engineers to consider wavelength as another dimension when designing communication network and switches.
  • Wavelength Switching: In contrary to wavelength-routed networks that are based on rigid fiber structure, wavelength-switched architecture allows you to reconfigure the optical layer efficiently.

What is the Operational Principle of WDM?

In traditional point-to-point links, signals coming from different light sources utilize separate optical fibers that are uniquely assigned to them. Therefore, such an optical source has a narrow linewidth and thus, it uses only a limited portion of the large transmission bandwidth capacity of a fiber.

However, with the advent of wavelength division multiplexing, the scenario has turned around. Now, we can utilize a wider portion of the available transmission bandwidth of a fiber.

To achieve that, a multiplexer is used to combine the optical outputs into a serial spectrum of closely spaced wavelength signals, which is then coupled onto a single fiber. Therefore, at the receiving end, a demultiplexer is also used to split the wavelength signals which are then directed to appropriate detection channels for signal processing.

To make this possible, such a system uses a variety of passive or active devices to combine, distribute, isolate, and amplify optical power at different wavelength.

The Role of Passive Components

Passive devices are designed to operate fully in the optical domain to split and combine light signals. Some of the examples include NxN optical couplers, power splitters, start couplers, and more.

Some of the WDM passive devices, such as optical fused WDM, are also used in EDFA (Erbium-Doped Fiber Amplifier) modules, communication systems, and optical fiber amplifiers.