| Project/Area Number |
10555109
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 展開研究 |
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| Research Field |
電子デバイス・機器工学
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| Research Institution | TOHOKU UNIVERSITY |
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Principal Investigator |
NAKAMURA Kiyoshi Graduate School of Engineering, Tohoku University, Professor, 大学院・工学研究科, 教授 (00005365)
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| Co-Investigator(Kenkyū-buntansha) |
TOKANOU Yuichi Tokin Corporation, Researcher, 商品開発研究所, 研究員
HONGO Satoshi Miyagi National College of Technology, Lecturer, 情報デザイン学科, 講師 (80271881)
YAMADA Ken Graduate School of Engineering, Tohoku University, Associate professor, 大学院・工学研究科, 助教授 (80134021)
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| Project Period (FY) |
1998 – 1999
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| Project Status |
Completed (Fiscal Year 1999)
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| Budget Amount *help |
¥11,600,000 (Direct Cost: ¥11,600,000)
Fiscal Year 1999: ¥4,900,000 (Direct Cost: ¥4,900,000)
Fiscal Year 1998: ¥6,700,000 (Direct Cost: ¥6,700,000)
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| Keywords | SH-type surface wave / KNbOィイD23ィエD2 / Tunable filter / LiNbOィイD23ィエD2 / ZnO film / Optical waveguide / Acousto-optic effect / KNbO_3結晶 / WDM光通信用波長可変フィルタ / Y-X LiNbO_3結晶 / Ti拡散 |
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| Research Abstract |
The purpose of this research project is to develop high efficiency tunable optical filters for wavelength-division-multiplexing (WDM) optical communication by utilizing interaction between high coupling SH (shear-horizontal)-type surface acoustic waves and optical TE- and TM-mode waves. The results obtained in this project are summarized as follows : 1. It has been shown that there exists the BGS wave, which is a pure shear surface acoustic wave, on the metalized surface of Z-axis cylinder cuts of KNbOィイD23ィエD2, and the electromechanical coupling factor KィイD12ィエD1 is very high, about 53%. 2. The change of refractive index induced by the BGS wave on Z-axis cylinder cuts of KNbOィイD23ィエD2 has been analyzed and the results revealed the index change to be 18 times larger than that of the conventional Rayleigh waves. 3. By depositing a ZnO film with a low shear wave velocity on the Y-X LiNbOィイD23ィエD2 substrate the leaky SH-type surface wave is turned into a non-leaky SH-type surface wave with no propagation loss and the KィイD12ィエD1 is as high as 21.4% for the ZnO film thickness about 0.1λ. This has been experimentally proved. 4. The refractive index change induced by the SH surface wave on ZnO/Y-X LiNbOィイD23ィエD2 has been shown theoretically to be large near the substrate surface compared with those of the Rayleigh waves. The coupling length needed for 100%TE-TM mode conversion has been calculated using the coupled-mode theory to be about 1/2.5 of that of the Rayleigh wave. 5. ZnO/Y-X LiNbOィイD23ィエD2 acousto-optic tunable filters have been designed and fabricated. The experimental evaluation of TE-TM mode conversion characteristics are now under investigation.
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