Dot-com era left 95-98% of US long-haul fiber dark; AI is now lighting it up

jwt0625 · x · 2026-09-09

The author marvels that overbuild during the dot-com boom was far bigger than expected. Citing Grok: after the bust, roughly 95-98% of US long-haul fiber sat dark (only 2.7% lit by 2003). Cloud providers and hyperscalers activated much of it from 2005 onward, and DWDM raised per-strand capacity. Recent estimates suggest 20-35% of fiber remains unlit globally or in key markets. AI demand is now rapidly lighting leftover 1990s strands, while new high-count cables still leave excess dark fiber. Precise ongoing tallies are scarce due to private ownership.

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