1987 Fiscal Year Final Research Report Summary
Basic Research for Guided-wave Light Modulation in Millimeter-Wave Region
| Project/Area Number |
61460142
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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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 | Osaka University |
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Principal Investigator |
IZUTSU Masayuki Osaka Univ, Fac Engrg Sci, Assoc Prof., 基礎工学所, 助教授 (70093375)
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| Co-Investigator(Kenkyū-buntansha) |
HAGA Hiroshi Osaka Univ, Fac Fegrg Sci, Assoc., 基礎工学部, 助手 (80172831)
SUETA Takasi Osaka Univ, Fac Engrg Sci, Prof., 基礎工学部, 教授 (20029408)
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| Project Period (FY) |
1986 – 1987
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| Keywords | Integrated optics / Guided-wave light modulator / Lithium niobate / Millimeter-wave light modulation / Band limited operation / Resonant electrode / 共振型電極 / 定在波型光変調 |
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| Research Abstract |
We have succeeded to modulate light beams by a millimeter-wave signal. A guided-wave light modulator was constructed using a newly designed resonant electrode put on a Ti indiffused LiNbO_3 waveguide subsrate and its performance was tested in 33 to 40GHz frequency range. With 220mW dreve power, 1-rad phase modulation was obtained at a center frequency 35.3GHz for 633nm wavelength. A measured 3-db bandwidth was 5GHz. A frequency spectrum of a modulated output light beam was measured by using a scanning Fabry-Perot interferometer. With 1W drive power of 37.7GHz, a spectrum of 1.5rad phase modulation was observed. It is believed that this is the first known light modulation experiment in millimeter-wave renge with a modulation index reached to the point of being usable in practical application.
The other significant result of the present research is that the advantage to limit the modulation bandwidth is sonfirmed from the experimental results for the light modulation in higher frequency region. To bring the operating frequency of the modulator up to the higher frequency range, new design concept for the light modulator has to be introduced. If a device is designed for millimeter-wave modulation with the conventional traveling-wave or lumped type structure, unreasonably high drive power will be required to obtain a practical modulation index.
We have proposed two types of modulator constructions, wherein standing-wave type and filter-line type electrodes are applied to the guided-wave modulations. The necessary modulating power is decreased framatically, while the bandwidth is sacrificed with these structures. They operate within limited range of bands around their resonant frequencies. Two modulators with these schemes were designed, constructed and tested their performances. They are operated successfully in 10 to 15 GHz frequency region. The same concept is applied to the millimeter-wave light modulator.
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