Wedoany.com Report-Apr. 27, NEC Corporation has successfully conducted Japan’s longest terrestrial free-space optical (FSO) communication, achieving a distance exceeding 10 kilometers. The demonstration involved transmitting data using focused light beams from Tokyo Skytree, Japan’s tallest structure, to a ground site approximately 3 kilometers away, and to a remote location outside Nasushiobara City, Tochigi Prefecture.
FSO technology employs narrow light beams to transmit data wirelessly, eliminating the need for physical cables or traditional radio frequencies. This method offers high-speed, high-capacity connections with minimal risk of interception or interference due to the focused nature of the beams. It also avoids the need for expensive radio spectrum licenses, making it a cost-effective solution.
A key challenge for FSO is maintaining stable connections over long distances, as atmospheric turbulence can disrupt the light beams. NEC’s engineers addressed this by adapting capture and tracking technology originally developed for satellite communications. This allowed the optical beams to stay aligned bidirectionally, even across significant distances and elevation changes.
The tests were conducted in two phases. In Nasushiobara City, a stable optical link was established over more than 10 kilometers. Additionally, a test from Tokyo Skytree’s observation deck, 350 meters above ground, successfully transmitted a beam to a receiver nearly 3 kilometers away, studying the impact of turbulence at varying altitudes.
“NEC’s technology ensures reliable high-speed data transmission over long distances, overcoming challenges posed by atmospheric conditions,” said a company spokesperson. The company aims to apply FSO in areas where fiber optic cables are impractical, such as ship-to-shore communications, disaster recovery networks, and secure backup systems.
NEC plans to reduce the size of its current 2-cubic-meter FSO system to a portable unit and targets commercialization by 2028. The company is also exploring the integration of quantum cryptography to enhance security, potentially enabling secure ground-to-satellite communications for critical infrastructure.
This achievement marks a significant step in advancing wireless communication technologies, offering versatile solutions for connectivity in challenging environments.
