The submarine fibre-optic cable

Assembled from 27 blocks · 2 evidence · 23 related

1. Story
2. The physical article that carries almost all intercontinental data, and the first surprise about it is how small it is. In deep water, where nothing much is expected to disturb it, a modern telecommunications cable is an unarmoured "lightweight" type of roughly 17–20 mm diameter — industry descriptions reach for a garden hose or a beer-bottle cap — weighing on the order of 0.7 kg per metre in air. Inside that sheath there is very little: a few pairs of glass fibres, each thinner than a human hair, held in a steel or polymer tube filled with water-blocking compound, wrapped in a helical layer of high-tensile steel strands that carry the tension of laying rather than the traffic, then a copper conductor tube that carries electrical power to the repeaters, then insulating polyethylene. Approaching land the same cable is rebuilt for a different threat: single or double layers of galvanised steel armour wire take the diameter up toward 50 mm and the weight toward 4.8 kg per metre, because the shallow shelf is where trawl doors and anchors are, and it is ploughed into the seabed to a depth typically quoted as one to three metres. The design logic is worth stating plainly, because it explains most of what follows: the cable is armoured where people are and almost naked where they are not, so the system is engineered around human interference rather than around the sea.
3. Knowledge
4. The submarine fibre-optic cable
5. The submarine optical repeater
6. The cable landing station
7. Connections
8. The cable landing station
9. The submarine optical repeater
10. The Convention for the Protection of Submarine Telegraph Cables
11. Latency as a physical quantity
12. Cables in the Luzon Strait break in sequence over nine hours
13. Cables and a power link are damaged in the Baltic Sea
14. The submarine fibre-optic cable
15. Cable power feed equipment
16. Porthcurno cable station
17. The Valentia Island cable station
18. The Heart's Content cable station
19. The submarine fibre-optic cable
20. Cable power feed equipment
21. The erbium-doped fibre amplifier
22. TAT-1 opens with 36 telephone circuits
23. The erbium-doped fibre amplifier is demonstrated
24. TAT-8, the first transoceanic fibre cable, enters service
25. Evidence
26. Supports the cable construction figures in this pack: unarmoured deep-water types of roughly 17–20 mm diameter, armoured shore-end types up to about 50 mm, weights of about 0.7 kg/m unarmoured to 4.8 kg/m double-armoured, and burial to a typical one to three metres. V55 verification basis: retrieved in summary only; www.iscpc.org is blocked to this session, and no manufacturer datasheet was opened. Every figure is a class range, not a specification for a named cable.
27. Supports the scale figures used in this pack: more than 600 active and planned systems and over 1.5 million route-kilometres in service as of early 2026, and the standard statement that submarine cables carry well over 95 per cent of international data traffic. V55 verification basis: retrieved by search, not opened — this session has no working WebFetch to telegeography.com. TeleGeography is a commercial research firm and is the de facto public register for this industry precisely because no public authority maintains one; the figures should be read as its counts on its own definitions, and they move every year.