1987 Fiscal Year Final Research Report Summary
Develoment of Two-Wavelength Laser Precise Distance-Measuring Instrument for Earthquake Prediction
| Project/Area Number |
61890008
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| Research Category |
Grant-in-Aid for Developmental Scientific Research
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| Allocation Type | Single-year Grants |
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| Research Field |
広領域
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| Research Institution | Hyogo University of Teacher Education (1987)
Kyoto Institute of Technology (1986) |
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Principal Investigator |
SHIGERU NAKAYAMA Hyogo University of Teacher Education, Associate Professor, 学校教育学部, 助教授 (00112714)
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| Co-Investigator(Kenkyū-buntansha) |
初田 洋司雄 日本電気(株), 誘導光電事業部, 部長
YOSHIO HATSUDA NEC Corporation, Guidance and Electro-Oprical Division, Director
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| Project Period (FY) |
1986 – 1987
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| Keywords | Distance measurement / Laser Range Finder / Electro-optic modulator / Re-entrant cavity / Earthquake prediction / Modulation method / 二波長レーザー |
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| Research Abstract |
In a laser distance-measuring instrument, there are several methods such as interformetric method, pulse method, and modulation method. To mesure medium distanced of one to fifty kilometers through atmosphere, the modulation method is most appropriate, which measures phase delay undergoing in traversing the distance. Terefore, a stable and efficient microwave electro-optic modulator must be developed for the accurate and precise measuement of distance through atmosphere by using the modulation method.
A re-entrant cylindrical cavity using a KDP crystal is constructed which has a high laser intersity modulation index. An electro-optic modulator which operates at a frewuency of around 3GHz in the S-gand microwave regin is analyzed and developed for use in a laser distance-measuring instrument. A reentrant cylindrical cavity id consturcted by using a KDP crystal inside the caviry. %The cabity efficiency is theoreticaly analyzed by finite element method. The modulator has s laser intensity modulation index of 8% which has been obtained with a microwave input peak power of 1 W. The modulator is tested in the laboratory for distance measurement with the result that the modulator is capable of measuring a distance with the instrumental accuracy of imm.
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