Dark Fibre

A dark fibre or unlit fibre is an unused optical fibre, available for use in fibre-optic communication.

The term dark fibre was originally used when referring to the potential network capacity of telecommunication infrastructure, but now also refers to the increasingly common practice of leasing fibre optic cables from a network service provider, or, generally, to the fibre installations not owned or controlled by traditional carriers. In common vernacular, dark fibre may sometimes still be called "dark" if it has been lit by a fibre lessee and not the cable's owner.

A dark fibre network or simply dark network is a privately operated optical fiber network that is run directly by its operator over dark fibre leased or purchased from another supplier. This is in contrast to purchasing bandwidth or leased line capacity on an existing network. Dark fibre networks may be used for private networking, or as Internet access or infrastructure.