---
title: "Inside Petal: Building the World’s First Petabit-Class Transoceanic Subsea Cable"
description: "Meta announced Petal, the first transoceanic subsea cable to deliver petabit capacity, connecting France and the United States over 7,000 km and expected to enter service in 2029. It will be the first subsea cable system to deploy multi-core fiber technology at scale, using 2-core fiber in a 24 fiber-pair system to achieve 1 Pbps. The cable overcomes the Shannon Limit by adopting spatial division multiplexing with multi-core fiber, requiring ultra-pure synthetic silica for low attenuation and counter-propagation to minimize crosstalk. Petal’s repeaters use a single-body 96 amp design with a Fan-In/Fan-Out interface to transition between 2-core and single-core fiber for amplification, staying within existing 18 kV power feeding limits. Built with NEC, Sumitomo Electric, and Orange, Petal represents the largest generational capacity increase of any repeatered subsea system."
---

# Inside Petal: Building the World’s First Petabit-Class Transoceanic Subsea Cable

[Meta](https://yomu.fyi/company/meta) · By Elizabeth Rivera Hartling, Pascal Pecci, Matthew Mitchell · Sep 21, 2026

**Type:** Announcement

## Summary

Meta announced Petal, the first transoceanic subsea cable to deliver petabit capacity, connecting France and the United States over 7,000 km and expected to enter service in 2029. It will be the first subsea cable system to deploy multi-core fiber technology at scale, using 2-core fiber in a 24 fiber-pair system to achieve 1 Pbps. The cable overcomes the Shannon Limit by adopting spatial division multiplexing with multi-core fiber, requiring ultra-pure synthetic silica for low attenuation and counter-propagation to minimize crosstalk. Petal’s repeaters use a single-body 96 amp design with a Fan-In/Fan-Out interface to transition between 2-core and single-core fiber for amplification, staying within existing 18 kV power feeding limits. Built with NEC, Sumitomo Electric, and Orange, Petal represents the largest generational capacity increase of any repeatered subsea system.

## Context

Subsea cables carry 99% of intercontinental data traffic, but capacity growth has been limited by the Shannon Limit. The industry has used spatial division multiplexing to increase fiber pairs, but further scaling requires new technology. Meta’s previous cables scaled from 8 to 24 fiber pairs, reaching 0.5 Pbps. Petal aims to double that to 1 Pbps using 2-core fiber.

## Approach / What changed

Petal uses 2-core fiber in a 24 fiber-pair system to achieve 1 Pbps. The fiber uses ultra-pure synthetic silica for low attenuation and counter-propagation to minimize crosstalk. The repeaters use a single-body 96 amp design with a Fan-In/Fan-Out interface to transition between 2-core and single-core fiber for amplification, staying within existing 18 kV power feeding limits.

## Takeaways

- Petal will be the first subsea cable to deploy multi-core fiber at scale, using 2-core fiber to double capacity per fiber without proportional power increase.
- The cable achieves 1 Pbps over 7,000 km, double the capacity of the previous 0.5 Pbps transatlantic cable Anjana.
- The repeater design uses a single-body 96 amp with FIFO interface to retain single-core amplification efficiency while supporting 2-core fiber.

## FAQ

### How does Petal achieve petabit capacity without increasing power?

Petal uses 2-core fiber technology that doubles capacity per fiber without a proportional increase in power. The repeater design uses a single-body 96 amp with Fan-In/Fan-Out interface and SDM pump-sharing architecture, staying within existing 18 kV power feeding limits.

### What is multi-core fiber and how does it reduce crosstalk?

Multi-core fiber has two cores in a single strand. Crosstalk is minimized by using ultra-pure synthetic silica for low attenuation and counter-propagating optical signals, resulting in nearly immeasurable crosstalk.

### When will Petal be operational and who are the partners?

Petal is expected to enter service in 2029. It is built in partnership with NEC as the turnkey system supplier, Sumitomo Electric Industries for the fiber, and Orange for the French landing.

**Tags:** [Multi-Core Fiber](https://yomu.fyi/topic/multi-core-fiber), [Networking](https://yomu.fyi/topic/networking), [Telecom](https://yomu.fyi/topic/telecom)

- Source: [Meta](https://engineering.fb.com/2026/09/21/connectivity/inside-petal-building-the-worlds-first-petabit-class-transoceanic-subsea-cable)
- Source URL: https://engineering.fb.com/2026/09/21/connectivity/inside-petal-building-the-worlds-first-petabit-class-transoceanic-subsea-cable
- Ingested by Yomu: 2026-09-21T12:00:11.082Z

[Read original post](https://engineering.fb.com/2026/09/21/connectivity/inside-petal-building-the-worlds-first-petabit-class-transoceanic-subsea-cable)