NTT has successfully delivered electric power exceeding 1W to a remote location over more than 10 km using a single optical fiber. This achievement, which marks the world's first instance of maintaining high-speed and high-quality communication while transmitting power through an optical fiber, was accomplished in partnership with Kitami Institute of Technology, part of the National University Corporation Hokkaido Higher Education and Research System (KIT).
NTT says the breakthrough paves the way for extending high-speed optical communication to underserved regions, including areas without electrical power, and establishing emergency communication methods through optical fiber in disaster-stricken situations. Traditional technology limited the distance over which power could be supplied to drive optical communication devices to under 10 km due to optical fiber input light intensity constraints.
In this experiment, NTT used multi-core optical fiber (MCF) with four optical paths (cores) with the same diameter as the commonly used optical fiber..
The MCF employed in this research matches the thinness of existing optical fibers, with each core exhibiting transmission characteristics identical to those of standard optical fibers. Each core can function independently, avoiding optical signal interference between cores, allowing for core allocation to power supply, communication or both.
In this study, to maximize optical power supply, a 1550 nm wavelength light source was introduced into four cores. Additionally, two of the four cores were allocated both up and down signals with a wavelength of 1310 nm, facilitating bidirectional optical communication. The configuration allowed for two sets of two-core combinations, creating two separate communication systems.
The capacity of optical power supply can be expressed as the product of transmission distance and supplied power. In this research, MCF was leveraged to maximize power supply per unit cross-sectional area and mitigate return light, which can degrade power supply efficiency. As a result, after transmitting MCF over a distance of 14 km, approximately 1W of power was obtained. This achievement translates to an optical power supply capacity of 14 watt/km, setting a world record.
NTT will present details of its research on October 4, 2023, at the 49th European Conference on Optical Communications (ECOC) in Scotland.
