What is Petal?
Meta has unveiled Petal, a subsea cable designed to deliver 1 Pbps (one petabit per second) across the Atlantic. The cable is planned to go live in 2029 and connect France and the United States. Meta says it is the world's first petabit-class transoceanic subsea cable.
The dual-core fiber approach
The traditional way to add capacity is to add more fiber pairs, but that means heavier cables and higher voltages. Meta instead redesigned the glass itself: by placing two independent light-guiding cores inside a standard strand, it achieves the equivalent of 48 fiber pairs with a 24-fiber-pair system. The company says this doubles capacity without increasing the cable's physical size or power needs.
Technical challenges and solutions
To keep signal loss low in the dual-core fiber, engineers used ultra-pure synthetic silica. Cross-talk between cores was reduced to nearly immeasurable levels through precise refractive-index tuning and counter-propagating optical signals. The roughly 100 repeaters needed to amplify signals over about 7,000 kilometers use a specialized interface that splits each dual-core fiber into two single-core fibers and merges them back. The system stays within existing 18 kV power equipment limits.
Who is involved?
Meta is working with three partners: turnkey supplier NEC engineered and manufactured the system; Sumitomo Electric Industries supplied the multi-core fiber; and Orange is managing the cable's landing on France's Atlantic coast and its integration into Europe's terrestrial network.
