1986 Fiscal Year Final Research Report Summary
A study on the three-dimensional optical circuits and technology
| Project/Area Number |
59420032
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| Research Category |
Grant-in-Aid for General Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Research Field |
電子機器工学
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| Research Institution | TOHOKU UNIVERSITY |
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Principal Investigator |
KAWAKAMI Shojiro Research Institute of Electrical Communication, Tohoku University, 電気通信研究所, 教授 (10006223)
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| Co-Investigator(Kenkyū-buntansha) |
SHIRAISHI Kazuo Research Institute of Electrical Communication, Tohoku University, 電気通信研究所, 助手 (90134056)
MIYAGI Mitsunobu Research Institute of Electrical Communication, Tohoku University, 電気通信研究所, 助教授 (90006263)
MINAKATA Makoto Research Institute of Electrical Communication, Tohoku University, 電気通信研究所, 助教授 (80174085)
NISHIDA Shigeo Research Institute of Electrical Communication, Tohoku University, 電気通信研究所, 教授 (70006211)
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| Project Period (FY) |
1984 – 1986
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| Keywords | Optical waveguide / Y-junction / Mode matching device / ECR etching / LiNb <O_3> / Optical modulator / Switch / Phase plate / 位相板 / ビーム変換 |
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| Research Abstract |
The purpose of the project is the development of 3-dimensional optical circuits and technology, which have gradual refractive index variations along the propagation-axis. The developed circuits have new functions as follows:
1. Application of radiation-wave; antenna coupled Y-junction waveguides,
2. Application of taper and coherent taper; mode matching device,
3. Application of reflaction and resonance; abrupt-bend waveguides.
Following new devices have been proposed, analized and partially fabricated based on the above mentioned concepts.
1. Antenna coupled Y-junction waveguides; To reduce radiation losses of Y-junctions refractive index near the branching region was reduced. The wide and low loss Y-junctions were actually obtained.
2. A fiber mode matching device between dissimilar optical waveguides; A single-mode tapered fiber with a rectangular core at one end and a circular core at the other was fabricated and basic performance was confirmed.
3. New waveguide-bend configuration; A structure has a low refractive-index region at the outside of the corner. Basic performance was confirmed.
4. Microfabrication for the 3-D optical waveguides; An ECR (electron cyclotron resonance) reactive ion etching system was introduced. Ion-etched LiNb <O_3> and Si <O_2> ridge waveguides were successively fabricated.
5. Perfect velocity matching LiNb <O_3> traveling-wave modulators; The modulator that comprises of a ridge-waveguide has about 1 THz modulation band-width and low driving voltage. 20 GHz modulation was confirmed experimentally.
6. Optical switches; (1) Miniaturized LiNb <O_3> directional-coupler was fabricated. (2) Carrier injection type <III> - <V> compound semiconductor switches are investigated. Refractive index changes was calculated and epitaxial growth films were fabricated by using a hand-made LPE equipment.
7. Branching circuit by beam transformation using phase plates; Design and fundamental experiments were made, and basic performance was confirmed.
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