2021 Fiscal Year Final Research Report

LED-based optical wireless communications in the solar-blind band

Research Project

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Project/Area Number	19H02145
Research Category	Grant-in-Aid for Scientific Research (B)
Allocation Type	Single-year Grants
Section	一般
Review Section	Basic Section 21020:Communication and network engineering-related
Research Institution	National Institute of Information and Communications Technology
Principal Investigator	Yoshinari Awaji 国立研究開発法人情報通信研究機構, ユニバーサルコミュニケーション研究所, 研究統括 (50358876)
Co-Investigator(Kenkyū-buntansha)	小島一信東北大学, 多元物質科学研究所, 准教授 (30534250) 吉田悠来国立研究開発法人情報通信研究機構, ネットワーク研究所フォトニックICT研究センター, 主任研究員 (50573036) 秩父重英東北大学, 多元物質科学研究所, 教授 (80266907)
Project Period (FY)	2019-04-01 – 2022-03-31
Keywords	光無線通信 / 深紫外LED / 光センシング
Outline of Final Research Achievements	Light in the deep ultraviolet (DUV) wavelength regime, with wavelengths below 280 nm, is known as the solar blind band, which is not affected by sunlight on the earth's surface. The solar-blind band is expected to allow high-speed optical wireless communications (OWC) even outdoors during the daytime. However, due to the lack of viable light sources, the achievable data rate in previous studies on DUV-OWC was only a few Mbps and did not meet the requirements for 5G and beyond. In this work, we have investigated a high-speed OWC system using AlGaN-based DUV LEDs, which have recently been developed for sterilization, measurement, and resin carving. We achieved >1 Gbps transmission outdoors under direct sunlight and revealed the unique emission mechanism of AlGaN LEDs that enables high-speed modulation. Furthermore, a Gbps-class wide-field-of-view solar-blind wavelength division multiplexing transmission was demonstrated experimentally.
Free Research Field	光通信
Academic Significance and Societal Importance of the Research Achievements	５G以降の無線アクセス網では、より広帯域なミリ波・テラヘルツ帯、そして"光"の活用が重要となる。光無線通信としては、LEDを用いた可視光通信（VLC)が知られるが、可視帯は陽光の影響が大きく、日中屋外での使用が制限される。本研究では、殺菌用途などで発展著しいAlGaN系深紫外帯LEDを用い、陽光の影響を受けない深紫外帯で通信することで、VLCのコンセプトを陽光下でも実現可能であることを実証した。また、AlGaN LEDが高速変調に好適な発光メカニズムを持ち、ギガビット級伝送が可能であることも明らかにした。以上により、深紫外帯の５G以降の新たな情報通信資源としての活用に端緒を得た。