Meta Unveils Petal, World's First Petabit-Class Transoceanic Subsea Cable Linking France and the US

Meta has announced Petal, the world's first transoceanic subsea cable designed to deliver petabit-class capacity, marking a significant leap forward in global communications infrastructure. The approximately 7,000-kilometer system will connect France and the United States and is expected to enter service in 2029, delivering 1 petabit per second (1,000 terabits per second) — roughly double what today's most advanced subsea cables carry at comparable distances. According to Meta, this capacity is equivalent to the network bandwidth required for approximately 75% of the world's population to stream music simultaneously.

Subsea cables form the least visible yet most critical layer of the internet, carrying approximately 99% of intercontinental data traffic — nearly every message, phone call, and video call between continents travels through glass strands on the ocean floor. Since the introduction of the erbium-doped fiber amplifier in the 1980s, the industry has experienced several transformational shifts in cable capacity. In the 2010s, coherent optical transmission technology and dispersion-uncompensated cable designs drove a decade of dramatic capacity increases of 10x and more, until the Shannon Limit pushed back on further gains. The industry then pivoted to spatial division multiplexing to increase the number of fibers within a subsea cable, with Meta scaling its approach from Marea's eight fiber pairs to Amitie's 16 fiber pairs and recently to Anjana's 24 fiber pairs — the first 0.5 Pbps transatlantic cable system.

With Petal, Meta has opted for 2-core fiber technology in a 24 fiber-pair system, equivalent to 48 fiber pairs, to achieve the leap to 1 Pbps at transatlantic distances. This represents the single largest generational increase in cable capacity of any repeatered subsea system ever built. The transition to a 2-core fiber ecosystem required overcoming significant engineering challenges affecting both the fiber itself and subsea repeaters. On the fiber side, engineers needed to ensure low attenuation while maintaining the physical dimensions of the outer fiber, including the 125-micrometer width, achieved through the use of ultra-pure synthetic silica during preform manufacturing. Minimizing crosstalk between the cores was accomplished by carefully controlling high refractive indexes in the cores against lower indexes within the surrounding medium and counter-propagating the optical signals, resulting in nearly immeasurable crosstalk.

A 7,000-kilometer subsea cable typically requires about a hundred repeaters to amplify digital signals along its length. Petal's single-body 96-amp repeater uses single-core fiber amplification with a Fan-In/Fan-Out interface to transition 2-core fiber into two single-core fibers within each repeater and then back to 2-core fiber following amplification. This design allows Petal to retain the highest efficiency and reliability of single-core amplification with an SDM pump-sharing architecture. The combination of FIFO, highly efficient amplification, and high-quality, low-loss fiber enables Petal to double capacity without a proportional increase in required power, remaining within existing power feeding equipment limits rated up to 18 kV.

Petal is being built in partnership with NEC and Sumitomo Electric Industries, with support on the French landing from Orange. NEC serves as the turnkey system supplier, having engineered and qualified the world's first petabit transoceanic system around a next-generation SDM foundation, and is responsible for manufacturing and installing the final product. Sumitomo Electric Industries, NEC's fiber supplier, developed and manufactured the 2-core fiber with ultra-low losses and practically immeasurable crosstalk for counterpropagating signals, achieving optical performance nearly identical to single-core fiber. Orange and Meta are working together on plans to land Petal ashore France's Atlantic coast, including terrestrial interconnection into the European network.

"Achieving petabit-per-second capacity across a transoceanic submarine system represents a major technological milestone in the history of global telecommunications," said Eduardo Mateo, Chief Strategy Officer of NEC Corporation's Submarine Network Division. "This achievement reflects NEC's sustained investment in research and development, combined with decades of experience delivering some of the world's most advanced, reliable, and secure submarine networks that interconnect the globe." Takehiko Okada, General Manager of Sumitomo Electric Industries' Optical Fiber & Cable Division, added, "We are thrilled that Sumitomo Electric's innovative submarine multi-core fiber, '2C Z-PLUS ULL Fiber,' will contribute to Petal, an epoch-making Pb-class transatlantic cable system." Jean-Louis Le Roux, EVP of Orange International Networks, noted, "Reaching one petabit on a transatlantic link, 25 years after the terabit milestone, represents a significant breakthrough to meet the exponential traffic growth while optimizing network capacity."

The announcement underscores Meta's position as one of the world's largest investors in subsea cable infrastructure, building the digital backbone that connects continents and strengthens the global internet. By moving multi-core fiber from experimental to mainstream, Meta aims to set a new standard for what undersea infrastructure can deliver and invite the broader ecosystem to invest alongside it. The Petal project is expected to reinforce connectivity between Europe and North America at a time of rapidly growing demand for reliable, high-capacity communications infrastructure.