title: Cavity-resonator-integrated grating input/output coupler for high-efficiency vertical coupling with a small aperture.
abstract: A cavity-resonator-integrated grating input/output coupler (CRIGIC) is designed to operate at about 850 nm wavelength for high-efficiency vertical coupling of a guided wave and a free-space wave with a small aperture. The CRIGIC consists of a grating coupler and a waveguide cavity resonator constructed by two distributed Bragg reflectors. A coupling efficiency of 96% with a 3 dB bandwidth of 1.2 nm is predicted by a theoretical calculation. An output coupling efficiency of about 60% is experimentally demonstrated on a 20 microm aperture device, fabricated in a thin-film SiO(2)-based waveguide on a substrate with an Au reflection layer, for what we believe to be the first time.
authors.affiliation: National Institute of Advanced Industrial Science and Technology, Central 2, 1-1-1 Umezono, Tsukuba, Ibaraki 305-8568, Japan. kintaka.kenji@aist.go.jp
authors.forename: Kenji
authors.initials: K
authors.lastname: Kintaka
authors.forename: Yuki
authors.initials: Y
authors.lastname: Kita
authors.forename: Katsuya
authors.initials: K
authors.lastname: Shimizu
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Matsuoka
authors.forename: Shogo
authors.initials: S
authors.lastname: Ura
authors.forename: Junji
authors.initials: J
authors.lastname: Nishii