TOKYO – Nippon Telegraph and Telephone (NTT), a major Japanese telecommunications company, has announced the development of a four-core multicore optical fiber (MCF) that can deliver four times the data capacity of conventional optical fiber while maintaining the exact same thickness and diameter.
The company emphasized that keeping the cable’s cross-section unchanged is critical for compatibility with existing infrastructure. This includes not only cable-laying vessels but also terrestrial interconnect systems and terminal racks, allowing the new fiber to integrate seamlessly without requiring major structural changes or costly overhauls.
Unlike traditional single-core optical fibers, the new MCF contains four separate cores surrounded by glass cladding. Using a technique called spatial multiplexing, signals can travel through each core independently. This allows a single fiber to carry four separate optical paths simultaneously. In undersea cables that typically bundle up to 48 fibers, this technology increases capacity significantly, enabling a single cable to support up to 192 cores.
To support real-world deployment, NTT has also developed several technical components designed for easy integration. These include a submarine joint box that connects conventional terrestrial fiber cables to the four-core undersea cable, as well as an MCF cable terminal that links the multicore fiber to transmission equipment originally designed for single-core systems. Additionally, a factory joint box allows two MCF cables to be connected directly on the seabed.
NTT expects the new multicore fiber technology to be ready for deployment by 2029. The innovation could help telecom companies increase network capacity while simultaneously reducing costs and deployment time, as it eliminates the need for a complete overhaul of existing submarine and terrestrial cable systems. This breakthrough arrives at a time of surging global demand for high-speed data transmission driven by artificial intelligence, cloud computing, and streaming services.
