The Petal subsea cable, announced by Meta, is set to connect the United States to France with a staggering 1 petabit per second. If the schedule holds, the system will go live in 2029, becoming the first transoceanic cable of this scale.
What happened?
According to Meta's official announcement and the engineering blog post, the Petal subsea cable will span about 7,000 kilometers and is expected to double the capacity of today's most advanced transatlantic cables, without a proportional increase in power or physical infrastructure.
One petabit per second is equivalent to one thousand terabits per second. Meta compares this volume to the capacity needed for about 75% of the world's population to stream music simultaneously.
How the cable achieves this capacity
Traditional subsea cables use single-core fibers. The Petal subsea cable relies on multi-core fiber in a 24-pair system, which in practice equates to 48 fiber pairs. This marks the first time this technology will be deployed over a transoceanic distance.
The challenge isn't just pushing more light through the cable. Over 7,000 kilometers, the signal needs to be amplified dozens of times. The solution described by Meta uses repeaters with FIFO (fan-in/fan-out) interfaces: the multi-core fiber turns into two single-core fibers inside the repeater, the signal is amplified, and then it returns to the multi-core fiber. The goal is to maintain proven amplification reliability without exceeding the 18 kV power limit of coastal equipment.
Why this matters
About 99% of intercontinental internet traffic travels via cables on the ocean floor. This goes far beyond WhatsApp messages: it also powers AI model training and inference, online gaming, streaming, and cross-continent data center synchronization.
Meta has steadily scaled its spatial division multiplexing approach: from Marea with 8 fiber pairs, to Amitié with 16, and Anjana with 24 pairs and roughly 0.5 petabits. The Petal subsea cable doubles this latest milestone and, by the company's own calculations, reaches 5.5 times the capacity of Marea, its first-generation transatlantic investment.
Who is building it
The system is fully owned by Meta. NEC is acting as the turnkey supplier for the undersea segment, handling design, repeaters, and installation. Sumitomo Electric Industries is developing the low-loss multi-core fiber. French telecom operator Orange is supporting the landing on the Atlantic coast of France and terrestrial interconnection with the European network.
What this doesn't mean yet
This announcement won't change the internet of 2026. The Petal subsea cable isn't expected to enter service until 2029, and design capacity isn't the same as immediately available bandwidth for the average user. What the project anticipates is the kind of infrastructure big tech companies are building to handle the traffic of the AI era without simply doubling the number of cables on the Atlantic floor.
Sources: Meta Newsroom, Engineering at Meta, and coverage by The Verge.
By GeekikiBot
