2023 Fiscal Year Final Research Report
Long Distance Underwater Wireless Optical Communication System using Visible Light Laser Array with Directivity Control Function
| Project/Area Number |
20K04937
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Review Section |
Basic Section 24020:Marine engineering-related
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| Research Institution | University of Yamanashi |
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Principal Investigator |
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| Project Period (FY) |
2020-04-01 – 2024-03-31
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| Keywords | 水中光無線 / 可視光レーザ / レーザアレイ / 水中通信 / 可視光LD |
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| Outline of Final Research Achievements |
This research project aimed to extend the transmission distance of gigabit-class underwater wireless optical communications by realizing a transmitter employing directional control of a visible light laser array. The proposed technique involved arraying low-power laser diodes with high-speed modulation bandwidth and concentrating their emission directions onto the receiving surface to enhance the transmitted optical power. Experiments demonstrated that using two laser diodes nearly doubled the received optical power and improved the bit error rate performance. Furthermore, to effectively utilize the narrow dynamic range of laser diodes and photodiodes, we investigated applying Tomlinson-Harashima precoding (THP) at the transmitter side. Employing THP improved the bit error rate characteristics and reduced the required received optical power by approximately 2 dB compared to conventional FIR pre-equalization.
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| Free Research Field |
水中光無線通信，通信方式，信号処理
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| Academic Significance and Societal Importance of the Research Achievements |
本研究課題で検討している水中光無線通信システムは，既存の入手性の高い広帯域・低パワーLDを複数用いることで，可視光デバイスの性能に頼らずに伝送距離の延伸化を図るものである．将来提供されるであろう高速変調が可能なハイパワーLDや広帯域・高感度PDと置き換えることが容易であることから，キロメートルオーダの伝送距離の実現も見えてくる．今後の高速光無線通信システムの発展に大きく寄与するものと考えている．本システムにより，広大な海洋の資源探査だけでなく，地震関連や港湾・橋脚等の水中楮物の調査に大きく寄与する高精細動画像の水中長距離無線伝送システムの実現が期待できる．
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