Nearly every video call to America runs through glass strands on the ocean floor. Nobody thinks about them until one breaks.
Meta announced its next such strand, and it is a different class. The company is not adding fibres to the cable. It is putting two cores into one fibre, at the same 125-micron thickness, the width of a hair.
Fact
The facts: on 21 September 2026 Meta announced the Petal subsea cable between France and the United States, about 7,000 kilometres long with a capacity of 1 petabit per second (1,000 terabits), which the company says is double what today's most advanced subsea cables carry at that distance. Petal will be the first subsea system to deploy multi-core fibre at scale: two-core fibre in a 24-fibre-pair system, equivalent to 48 fibre pairs. It is being built with NEC as the turnkey system supplier and Sumitomo Electric Industries as the fibre supplier, while Orange supports the French landing and the connection into the European network. The repeaters stay within existing power-feeding limits of up to 18 kilovolts. Service is expected in 2029. Per Meta, about 99% of intercontinental data traffic travels over subsea cables, and Petal will have 5.5 times the capacity of Marea, their first transatlantic cable.
Why two cores
Because, per Meta, one petabit cable uses far fewer materials and resources than two half-petabit systems. If you double the capacity in the same strand without raising the power, you avoid both a new cable and a requalification of all the equipment along the route.
This is the craft that rarely makes the news: not bigger, but denser. Sumitomo's engineers have made the two cores almost unable to hear each other. NEC makes the repeaters - a route like this typically needs about a hundred - that split the light from the two cores, amplify it and put it back together.
The internet grows inward, inside a strand as thin as a hair.
Meta says it wants multi-core fibre to become a normal choice for the whole industry. That will be testable when another company's next cable takes the same road.
Until then Petal is a plan with a date. If it arrives on time, in three years there will be a cable between Europe and America with double the capacity of today's most advanced ones.
Official primary sources
Engineering at Meta - Inside Petal: Building the World's First Petabit-Class Transoceanic Subsea Cable, 21.09.2026The visual is generated code-art, no third-party images.