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What is Dark Fibre?

What is Dark Fibre?

The traditional meaning of Dark Fibre refers to unused or ‘dark’ network infrastructure that is a mixture of cabling, switches and repeaters. Data is transported over optical fibre networks by passing light through the cables. If there is no data being transported, there is no light – this means that the fibre is ‘dark’. Dark Fibre is essentially optical fibre infrastructure that is not in use.

When fibre optic cables are laid down, many companies will, in order to future-proof their networks from exponential data growth, overestimate the amount of infrastructure and cabling required. This overestimation coupled with technical advances in the way in which data is packaged means that many optical fibre networks have extra capacity that is not being used. As a result, Dark Fibre networks have developed to take advantage of this extra capacity.

The term ‘Dark Fibre’ has now evolved to encompass the practice of leasing ‘dark’ fibre optic cables from network providers and operators. A client will lease unused strands of ‘dark’ fibre optic cable to create their own privately-operated optical fibre network rather than just leasing bandwidth. The Dark Fibre network is separate from the main network and is controlled by the client rather than the network provider.

Dark Fibre networks can be set up in a variety of ways, including dark fibre rings, point to point or point-to-multipoint configurations. With Dark Fibre, a client can expect to get high levels of performance, a highly secure network and superfast speeds.

DWDM (Dense Wavelength Division Multiplexing) has been key in the development of Dark Fibre. DWDM is where multiple data signals are transmitted simultaneously over the same optical fibre. Though the data signals are transmitted at the same time, they are transmitted at different wavelengths to keep the data signals separate. DWDM is a method of increasing bandwidth and allowing more data to be sent via optical fibre. Simply put, with DWDM a single optical fibre cable is transformed into multiple virtual fibres.

There are many benefits to using ‘dark’ networks. They require less power and have a higher capacity, generally due to the use of DWDM. Dark Fibre often has better signal strength and is more immune to interference than the fibre making up traditional networks.

For more information on Interoute’s Dark Fibre Network visit our Dark Fibre page