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Kiichi YOSHIARA Fusaoki UCHIKAWA Ken SATO Takashi MIZUOCHI Tadayoshi KIYAYAMA Masayuki IZUTSU Tadashi SUETA Katsuhiro IMADA Hisao WATARAI
This paper describes on the transmission properties of the superconducting coplanar waveguide on LiNbO3 (LN) substrates, fabricated by YBa2Cu3Oy (YBCO) superconducting films. The films have been prepared by the reactive co-evaporation method and patterned by a wet etching process. The surface resistance of the obtained film was 0.04 Ω at 18 GHz and 77 K. It was confirmed from X-ray diffraction (XRD) that these films were highly oriented to the direction of c-axis without a secondary phase. The microwave transmission properties of these YBCO coplanar waveguides were investigated at frequencies up to 20 GHz and compared with that of the aluminum coplanar waveguide. The characteristic impedances of both coplanar waveguides were designed to be 50 Ω. It was found that the attenuation constants of these samples at 77 K were less than that of the aluminum coplanar waveguide for frequencies below 18 GHz.
Kiichi YOSHIARA Fusaoki UCHIKAWA Takashi MIZUOCHI Tadayoshi KITAYAMA Katsuhiro IMADA Iwao KAWAMATA Shigeru MATSUNO Shin UTSUNOMIYA
The characteristics of a LiNbO3 light modulator using the resonant YBa2Cu3Oy superconducting electrode were studied on the basis of the calculated results of surface resistances and transmission losses. The two-fluid model and the conventional transmission theory were used for the calculations. It was found that the modulation depth of this modulator using the YBCO electrode at 77 K was 7.5 times that using the Al electrode at room temperature. The drive voltage for the phase modulation of π radians was estimated to be a very low value of 2.3 V.
Kiichi YOSHIARA Fusaoki UCHIKAWA Takashi MIZUOCHI Tadayoshi KITAYAMA Katsuhiro IMADA Iwao KAWAMATA Shigeru MATSUNO Shin UTSUNOMIYA
The characteristics of a LiNbO3 light modulafor using the resonant YBa2Cu3Oy superconducting electrode were studied on the basis of the calculated results of surface resistances and transmission losses. The two-fluid model and the conventional transmission theory were used for the calculations. It was found that the modulation depth of this modulator using the YBCO electrode at 77 K was 7.5 times that using the Al electrode at room temperature. The drive voltage for the phase modulation of π radians was estimated to be a very low value of 2.3 V.