NEC Corporation has successfully achieved the longest land wireless optical communication in Japan, or optical free space communication (FSO), at a distance of more than 10 km. In addition, NEC has successfully done FSO communications Among an observation cover in Tokyo Skytree, the highest structure in Japan and a location on the ground approximately 3 km away, which represents a significant change in elevation.
FSO is a wireless communication method that allows high -speed communication and high capacity compared to radio waves. It transmits and receives light beams without using physical routes such as optical fibers. In addition, it has a high directionality and beams is not propagated, resulting in a low risk of interception by third parties, a reduction in interference and congestion in communication, and there is no need for permits for the use of radio waves.
These recently developed technologies are expected to be used for communications in locations and regions where it is difficult to install optical fiber and for communications between ships in the sea and the earth. In addition, technologies are expected to be used as an alternative or emergency communication method in case of a disaster when cable communication networks are damaged, which makes communications difficult, as well as for highly confidential communications of short and medium -median rank related to national security.
Conventionally, one of the challenges for FSO communications has been to overcome the negative impact on stable communications of atmospheric turbulence, such as heat mist, which increase with distance, and it has been difficult to understand the atmospheric turbulence that differs between different elevations.
NEC has now achieved successful communication in a distance of more than 10 km and communications in different elevations with FSO communication by applying its developed capture and monitoring technology for its long -distance optical communication and technology systems of optical communication used in satellites.
General description and results of the demonstration experiment
① Long distance test
- Location: City of Nasushiobara, Prefecture of Tochigi, Japan
- Period: January to February 2025
- Content: NEC made a communication demonstration between a couple of FSO communication devices located more than 10 km away in the city of Nasushiobara, Prefecture of Tochigi. As a result, NEC confirmed that automatic capture and monitoring of bidirectional optical beams functioned correctly even at long distances, allowing communication.
② Elevation difference test
- Location: Tokyo Skytree, plunged Ward, Tokyo, Japan
- Period: March 2025
- Content: NEC demonstrated the FSO communication between the roof of a Tokyo Skytree observation deck, which is 350 meters above the ground level, and a point on the ground approximately 3 km away. As a result, NEC confirmed that communication was possible and also measured the effects on atmospheric turbulence communications due to elevation differences.
Nec will advance technological development based on the success of this demonstration, with the aim of improving the quality of communication and reducing the size of the device from approximately 2 m³ to approximately 1% of the current size, so it can be carried by a person, with plans to market it by 2028. Distribution technology in the future, thus allowing a safer communication. NEC also aims to apply this technology to communications between land and satellites while continuing to advance its efforts to provide networks adapted to the diverse needs of its customers.
