What is Dark Fibre?

What is Dark Fibre?

Dark fibre refers to fibre optic cables that have no equipment at either end, meaning it is “dark” and “unlit”. As dark fibre isn’t shared but dedicated to an organisation, it offers significantly higher capacity and lower latency than broadband and leased lines. Its capacity can be further extended through wavelength division multiplexing (WDM).

As organisations grow, they require more bandwidth, but this can become an expensive endeavour, so they turn to dark fibre to help provide substantially more bandwidth. However, sometimes it’s more about latency, particularly in financial applications where time is of the essence in automated high-frequency trading platforms.

When designing a dark fibre network, multiple dark fibre links are laid instead of just one. The extra bandwidth may be reserved for future use and even leased out to other organisations, which although increase upfront costs, it can provide a regular revenue stream, which decreases operating costs.

Wavelength Division Multiplexing (WDM)

Wavelength division multiplexing (WDM) expands fibre capacity further by combining client connections into one single connection. This has a clear financial incentive as changing the electronics at the ends of fibre optic cables to drastically more cost-effective than placing more fibre in the ground.

More information can be found on our Guide to Wavelength Division Multiplexing.