2006 Fiscal Year Final Research Report Summary
Studies on mode multiplexers using multimode interference optical-waveguide couplers
| Project/Area Number |
16560298
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Electron device/Electronic equipment
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| Research Institution | Kyoto Institute of Technology |
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Principal Investigator |
TSUTSUMI Kiyoshi Kyoto Institute of Technology, Graduate School of Science and Technology, Associate Professor, 工芸科学研究科, 助教授 (50111993)
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| Project Period (FY) |
2004 – 2006
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| Keywords | optical waveguides / mulitimode interference waveguide couplers / multiplexing / demultiplexing of guided modes / finite difference beam propagation method / finite difference time domain method / electron beam lithography / patterning by stage translation |
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| Research Abstract |
In this study, the wavelength characteristics and the time response of mode multiplexers/demultiplexers using multimode interference (MMI) waveguide couplers are analyzed, and patterning of waveguides by electron beam lithography is discussed.
The wavelength characteristics are calculated by the finite difference beam propagation method (FD・BPM). When the incident modal order is high, higher order modes are excited in the interference region of MMI coupers and these modes may narrow the bandwidth. A method of limiting interfering modes properly is proposed. By this method the utilizable bandwidth was increased.
The temporal response is analyzed by the finite difference time domain (FDTD) method. It is shown that MMI couplers exciting higher order modes have larger reflection. The length of interference region of mode demultiplexing units was improved to obtain higher output.
The computer-controlled electron beam lithography system used in this study has the mechanical stage with inchworm motors and optical encoders. Patterning of waveguides using stage translation is discussed and a method of control of translation is proposed. By using the method the accuracy of less than ten nanometers in average and hundred nanometers at maximum was obtained for the translation of one millimeter.
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