Cavity-resonator-integrated grating input/output coupler for high-efficiency vertical coupling with a small aperture.
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.
Kintaka
Kenji
K
National Institute of Advanced Industrial Science and Technology, Central 2, 1-1-1 Umezono, Tsukuba, Ibaraki 305-8568, Japan. kintaka.kenji@aist.go.jp
Kita
Yuki
Y
Shimizu
Katsuya
K
Matsuoka
Hitoshi
H
Ura
Shogo
S
Nishii
Junji
J