Wavelength Division Multiplexing

Wavelength Division Multiplexing (WDM) is a technology that can enable the capacity of optical fibre to be expanded by adding and multiplexer and a demultiplexer at each end of the fibre. This enables different streams of data to be sent over a single optical fibre simultaneously. Simply put, WDM allows the light to be split into different light channels – or wavelengths – which have a different frequency meaning they can be transmitted simultaneously. This can help optimise already existing network infrastructures removing the need to lay more fibre which can be extremely costly and take a lot of time.

Traditionally WDM technology was used for large networks like national infrastructures due to the complexity and cost, but these days there are WDM solutions out there that are more cost-effective whilst still being able to meet the needs of businesses.

There are two types of WDM available:

  • Coarse WDM (CWDM) uses less than 8 active wavelengths per fibre and generally used for connectivity across shorter distances and is more cost-effective.
  • Dense WDM uses precision lasers to create up to 80 channels of 100Gbps wavelengths and would typically be used on a core network where high capacity is required, so DWDM is a good choice for businesses dealing with large data volumes, such as eCommerce and Media and Service Providers whose customers require dedicated connectivity at high bandwidth.

For those businesses that own or are looking to lease Dark Fibre, the cost is usually significant, so taking advantage of WDM technology to maximise the capacity can help offset some of that cost. Carrier wavelengths are also available too, and although will side-step the large outlay for equipment and the need for in-house expertise, businesses need to lease the the number of wavelengths required which can limit capacity available and the ease of scalability.

Business need to evaluate the pros and cons of each. You can read more in our Dark Fibre vs Lit Fibre guide here.

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