Seren to build up to 350Tbps Juno cable

Seren, a new fibre optic cable operator backed by NTT and others, is set to build an up to 350Tbps  submarine cable system between Japan and the United States called ‘Juno’.

The Seren Juno Network Co will build and operate the 10,000km cable, touted as the largest of its type between the two countries.

The company is backed by NTT Japan, Mitsui, PC Landing and JA Mitsui Leasing.

They said in a joint statement that Juno “is very much needed to meet the increasing demand for global internet bandwidth”, particularly with “existing Japan-US cables nearing capacity”.

“This new subsea cable is the latest joint effort NTT has led in a long and proud history of providing reliable global internet infrastructure,” NTT Japan’s CEO and president Takanobu Maeda said.

The cable itself will use space division multiplexing (SDM) technology, “enabling the provision of 20 optical fibre pairs - 40 cores  per cable”, compared to a maximum of 16 fibre pairs or 32 cores on conventional cable systems.

It is also designed to be resilient to “rough weather conditions” on the Japan coast, which can be impacted by typhoons during the hotter months.

It appears the cable will land in two places on Japan’s Pacific coast - Chiba prefecture, near Tokyo, and Mie prefecture, which is adjacent to Nagoya. It will land in California on the US side.

The Juno cable is expected to begin operating at the end of 2024.