title: Air-gap structure between integrated LiNbO3 optical modulators and micromachined Si substrates.
abstract: The air-gap structure between integrated LiNbO(3) optical modulators and micromachined Si substrates is reported for high-speed optoelectronic systems. The calculated and experimental results show that the high permittivity of the Si substrate decreases the resonant modulation frequency to 10 GHz LiNbO(3) resonant-type optical modulator chips on the Si substrate. To prevent this substrate effect, an air-gap was formed between the LiNbO(3) modulator and the Si substrate. The ability to fabricate the air-gap structure was demonstrated using low-temperature flip-chip bonding (100 °C) and a Si micromachining process, and its performance was experimentally verified.
authors.affiliation: Department of Precision Engineering, The University of Tokyo, 7-3-1 Hongo, Tokyo, 113-8656, Japan. takigawa.ryo@su.t.u-tokyo.ac.jp
authors.forename: Ryo
authors.initials: R
authors.lastname: Takigawa
authors.forename: Eiji
authors.initials: E
authors.lastname: Higurashi
authors.forename: Tadatomo
authors.initials: T
authors.lastname: Suga
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Kawanishi