Meta plans a 1-petabit transatlantic cable for 2029

If nearly three-quarters of the world streamed music at the same moment, the flood of data would be enormous. Meta wants to carry a share of that traffic across the Atlantic through glass strands laid over 4,300 miles of deep ocean floor. The project is called Petal, and the company says it is set to go live in 2029.

Under the sea, the internet runs on fiber-optic cables, bundles of thin glass threads that carry light. Subsea cables still carry nearly 99 percent of international data traffic, but they are reaching hard limits. Operators facing growing AI workloads, video and cloud services have usually added more fiber pairs to a cable, and that makes it heavier, requires larger ships and pushes operating voltages up. Meta's approach is to change the glass itself: it packs two independent light-guiding cores into a single standard strand. Meta says this doubles bandwidth without making the cable physically bigger or raising its power needs. Petal uses 24 fiber pairs of this two-core design, the equivalent of 48 fiber pairs.

The engineering is delicate. Meta says its teams kept signal loss low by using ultra-pure synthetic silica, and kept interference between the two cores nearly unmeasurable through precise tuning of the glass's refractive index, the property that bends light, along with counter-propagating optical signals. Along a route of about 7,000 kilometers, the signal must be boosted by roughly 100 repeaters placed on the seabed. Petal uses a single-body 96-amp repeater fitted with a Fan-In/Fan-Out interface, which splits each two-core fiber into two single-core fibers for amplification, then merges them back. Meta says the system stays within existing 18 kV power equipment limits, which avoids costly requalification of subsea infrastructure.

Meta's own predecessor cable, Anjana, is the reference point: the company says the same method could double its capacity to 1 Pbps over transatlantic distances. For Meta, that means more traffic on a single route without building a second cable to the same standard. For the countries and networks at each end, Orange will connect the cable to Europe's terrestrial network on France's Atlantic coast. NEC is supplying the complete system, including cable, repeaters, power systems and installation, and Sumitomo Electric is providing the multi-core fiber. The sources give no cost, no list of customers and no capacity split between users, so the reach of the 2029 service is still unclear.

Meta describes Petal as the world's first petabit-class transoceanic subsea cable, and presents it as a shift that the whole industry could adopt. These claims come from the company and its partners, and the cable has not yet been laid. Its real performance will be known only once it is installed and carrying traffic, in 2029 if the schedule holds.