Undersea cables now account for more than 99% of international data traffic, but a robust terrestrial network is also vital for ensuring, high-capacity data flows across continents. To ensure the success of the highest-capacity Trans-Pacific cable linking Japan and the US, Lumen Technologies will provide the terrestrial backhaul connectivity for the JUNO Trans-Pacific cable system.
Operated by Seren Juno Network Co, the JUNO cable is 10,000 kilometres long and is engineered to deliver up to 350 Tbps across 20 fibre pairs, using next-generation Space Division Multiplexing (SDM) technology.
The line was constructed due to the massive upward growth trajectory of data driven by the deployment of 5G, internet of things (IoT), edge compute technologies and artificial intelligence (AI). With existing Japan-US cables nearing capacity at the beginning of the decade, Seren said JUNO was needed to meet the increasing demand for global internet bandwidth.
The JUNO submarine cable system officially achieved point of presence (PoP) to PoP ready for service (RFS) status on 30 May 2025, including the completion of terrestrial backhaul connectivity on both the Japanese and the US sides.
Seren said that it built the line to provide fast and reliable network services to global major global technology companies, OTTs and telecommunication carriers by enabling them to strengthen the telecommunications environment in the US and Asia through reliable and secure sales, operations and management support.
Seran added that businesses in both Japan and the US stand to benefit significantly from the increased bandwidth and reliable connections. It was confident that JUNO’s cable system and Lumen’s terrestrial network will create a powerful bridge between Asia and North America – supporting next-gen applications, enabling global scale for AI and helping enterprises navigate the digital economy with “agility and speed”. Seren stressed that connecting directly into cloud regions, edge compute sites and major datacentres is only possible with strong terrestrial backhaul.
Lumen’s dark fibre backhaul will now gives JUNO custom, private network configurations. Lumen’s fibre network will carry traffic from the cable’s US landing point in Grover Beach in California to two major PoPs in San Jose and Los Angeles, helping to “revolutionise business operations and technological advancements” in both the US and Japan. Connecting JUNO at the cable landing station to two critical PoPs will help data reach major cloud hubs, datacentres and enterprise networks across the US.
“Our partnership with Lumen is a critical milestone in delivering on JUNO’s promise to revolutionise trans-Pacific data transport,” said Yoshio Sato, CEO of Seren Juno Network Co. “Lumen’s reach into major US cloud hubs and its proven expertise in high-capacity fibre infrastructure make it an ideal partner as we bring the world closer through digital innovation.”
“Lumen designed and developed a dark fibre solution the JUNO system could quickly deploy to meet their launch date. Our critical fibre backbone enables the seamless high-capacity transport from Asia into the heart of the US digital economy,” said Lumen executive vice-president and chief revenue officer Ashley Haynes-Gaspar. “This level of control, scale and performance is exactly what global enterprises and cloud providers need to support the next generation of AI and data-driven innovation.”
