| Project/Area Number |
14350189
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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 | 一般 |
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| Research Field |
電子デバイス・機器工学
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| Research Institution | HIROSHIMA UNIVERSITY |
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Principal Investigator |
SUNAMI Hideo Hiroshima University, Research Center for Nanodevices and Systems, Professor, ナノデバイス・システム研究センター, 教授 (10311804)
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| Co-Investigator(Kenkyū-buntansha) |
YOKOYAMA Shin Hiroshima University, Research Center for Nanodevices and Systems, Professor, ナノデバイス・システム研究センター, 教授 (80144880)
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| Project Period (FY) |
2002 – 2004
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| Project Status |
Completed (Fiscal Year 2004)
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| Budget Amount *help |
¥14,500,000 (Direct Cost: ¥14,500,000)
Fiscal Year 2004: ¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 2003: ¥3,000,000 (Direct Cost: ¥3,000,000)
Fiscal Year 2002: ¥9,300,000 (Direct Cost: ¥9,300,000)
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| Keywords | Optical modulator / SOI / Comb-shaped transistor / Free carrier / Infrared light absorption / Optical waveguide / 透明電極 / 赤外吸収 / 自由電子赤外光吸収 |
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| Research Abstract |
This research is aiming to realize a silicon optical modulator based on free-carrier absorption. One of the most important key factors to realize the modulator is how much free carriers can be provided for interaction between carriers and infrared light. Thus, comb-shaped MOS transistors were developed and evaluated.
In a first trial, the optical modulation for a silicon optical modulator on SOI (silicon-on-insulator) of 1 μm in height and 1 mm in length could not be observed because that incident infrared light (wavelength, λ=1.55μm) slipped out into silicon substrate and heavily-doped polysilicon gate absorbed the light. However, multi-channel MOS transistors were successfully developed and academically proposed.
The second trial planning to solve the above issues has not brought about a successful modulation. The main cause is that the strength of noise light running through silicon substrate is more than 1000 times greater than that of signal light coming through inside silicon waveguide causing fatally bad signal-to-noise ratio.
Analyzing the experimental, it is estimated that the noise light has to be reduced to great extent. Thus, a device structure with infrared light absorption region in silicon substrate has been proposed. A trench in the substrate filled with carbon black has reduced the noise light efficiently. Another trial to realize the silicon optical modulator with improved structure has been carried out to date.
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