In a groundbreaking development, NTT and Hokkaido's Kitami Institute of Technology have successfully demonstrated a technology capable of supplying over 1 watt of electrical power to an unpowered location situated more than 10 kilometers away. The research partners made this possible while simultaneously maintaining high-speed, high-quality communication via a single optical fiber. Their achievement opens up a multitude of possibilities in various sectors, including remote and disaster-stricken regions that lack a reliable power supply.

The breakthrough is centered around multi-core optical fiber (MCF), which features multiple optical pathways or cores. What sets MCF apart is its compatibility with existing optical fibers, as both have the same glass diameter and similar transmission characteristics. Each core in the MCF can function independently, without interference from other cores. This unique feature allows any given core to be allocated for either power feeding or communication, or both. In NTT and Kitami Tech's research, four cores were used to maximize the output power for optical power feeding, while two were employed for bi-directional optical communication.

Their world-record performance metrics are startling. Researchers achieved a 1 W × 14.1 km (14.1 Wkm) using MCF, making it the world's highest self-power supply transmission capability. They also established a self-powered bi-directional optical communication system with a data rate of 10 Gbps—the fastest data rate commonly used for personal optical communication. The highest transmission performance of 140 Gbit/s･km was achieved, considering the multiplicity factor of the data rate and transmission distance as an index of transmission performance in self-optical feeding transmission.

For the duration of the research, NTT focused on optimizing MCF and evaluating the system's transmission characteristics, while Kitami Tech clarified the optical power supply capabilities of the manufactured MCF. They definitively showed that MCF technology can be deployed both for typical long-distance high-speed optical communications and for power-over-fiber-based communications. This dual functionality enhances network resilience, particularly during disasters or emergencies, by enabling remote powering of communication devices.

Communication technology has expanded rapidly into various facets of daily life, yet remains impeded by issues related to power supply. In regions where electrical power is hard to come by or in disaster-prone areas where power outages are frequent, this new technology holds immense promise. Previously, supplying power over 10 kilometers was impractical due to limitations related to the optical input power of optical fibers. However, NTT and Kitami Tech's research on MCF has effectively done away with this obstacle, enabling both long-distance high-speed optical communication and bidirectional power supply.

The applications of the technology are far-reaching. Beyond its obvious benefits in disaster recovery and emergency communications, it has several other potential uses, including:

The teams at NTT and Kitami Institute of Technology have taken a giant leap towards creating a future where optical communication can be available anywhere, at any time, under almost any circumstances. Their innovative work heralds an era of improved network resilience and more equitable access to communication technologies across the globe.

NTT—Innovating the Future of Communication

Daniel O'Connor

Daniel O'Connor joined the NTT Group in 1999 when he began work as the Public Relations Manager of NTT Europe. While in London, he liaised with the local press, created the company's intranet site, wrote technical copy for industry magazines and managed exhibition stands from initial design to finished displays.

Later seconded to the headquarters of NTT Communications in Tokyo, he contributed to the company's first-ever winning of global telecoms awards and the digitalisation of internal company information exchange.