Japan, April 25 -- NEC Corporation has successfully achieved Japan's longest terrestrial wireless optical communication, or free-space optical (FSO) communication, over a distance of more than 10 km. In addition, NEC has successfully conducted FSO communications between an observation deck at TOKYO SKYTREE(R), the tallest structure in Japan, and a location on the ground approximately 3 km away, representing a significant change in elevation.FSO is a wireless communication method that enables high-speed and high-capacity communication compared to radio waves. It transmits and receives light beams without using physical paths such as optical fibers. Additionally, it has high directionality and does not spread beams, resulting in low risk of i...