What is dark fibre?

Dark fibre is unlit, unused optical fibre cable leased as raw infrastructure — the buyer provides their own optical equipment to light it. Lit fibre comes as a managed service with the provider's equipment already active. Enterprises, hyperscalers, and carriers buy dark fibre for maximum control over capacity, latency, and security. Typical lease costs run $5-15 per metre per year on long-term IRUs (Indefeasible Rights of Use), usually 15-25 year terms. Dark fibre is essential for connecting data centres within a campus or metro area where sub-millisecond latency and unlimited bandwidth scaling matter.