Coupling-loss reduction of a vertically coupled microring resonator filter by spot-size-matched busline waveguides.
To improve the input-output coupling loss of a vertically coupled microring resonator filter, we fabricated microring resonators on an antiresonant reflecting optical waveguide (ARROW) with a large spot size and on the rectangular busline waveguide with a spot-size transformer. The spot size and the tapered structure were optimally designed from the viewpoint of spot-size matching to single-mode fibers and the reduction of radiation loss. Clear dropping responses were demonstrated for the ARROW-based microring resonator filters, and the coupling loss was successfully reduced by 22 dB.
Kato
Tomoyuki
T
Graduate School of Engineering, Yokohama National University, Japan.
Suzuki
Shuichi
S
Kokubun
Yasuo
Y
Chu
Sai Tak
ST