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Limits RegistryResearchers from Toshiba Europe and collaborating institutions reported twin-field quantum key distribution over more than 1,000 km of standard telecommunications fiber, extending the practical range of fiber-based QKD roughly an order of magnitude beyond earlier point-to-point QKD records by bypassing the fundamental rate-distance limit that constrains conventional QKD protocols. Because this is an active, fast-moving experimental research area with results reported across several papers, the precise headline figure should be read as an approximate 'over 1,000 km' milestone rather than one fixed number.
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Researchers from Toshiba Europe and collaborating institutions reported twin-field quantum key distribution over more than 1,000 km of standard telecommunications fiber, extending the practical range of fiber-based QKD roughly an order of magnitude beyond earlier point-to-point QKD records by bypassing the fundamental rate-distance limit that constrains conventional QKD protocols. Because this is an active, fast-moving experimental research area with results reported across several papers, the precise headline figure should be read as an approximate 'over 1,000 km' milestone rather than one fixed number.
The greatest single-span optical-fiber distance over which secure key material has been generated using twin-field quantum key distribution, without a trusted intermediate node.
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Permanent ID limitsregistry.com/limits/LR-TWIN-FIELD-QKD-FIBER-DISTANCE
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Limits Registry. LR-TWIN-FIELD-QKD-FIBER-DISTANCE. Longest-distance quantum key distribution over deployed optical fiber. 2026.