Definitions for "Dark Fibre"
Dark fibre is optical fibre infrastructure (cabling and repeaters) that is currently in place but is not being used. Data broadcasting - Data can be broadcast or transmitted to users over various wireless and cable mediums. The most typical are radio broadcasts (VHF, UHF, satellite) and cable broadcasts (such as simple cable television).
Fibre optic cable that has been laid but is not currently used.... more on: Dark fibre
Fibre optic cable that has been purchased by a non carrier/ISP in order to lay (into the ground) and light it for their own use. Dark fibre does not have any transmission equipment attached to the fibre links at this point in time. Dark fibre becomes lit fibre once it is being lit (through optical transmission equipment) and managed by a party (usually a carrier/ISP).