[11p-B11-1~14] 3.10 Photonic structures and phenomena

4:45 PM - 5:00 PM JST(7:45 AM - 8:00 AM UTC)English Presentation

[11p-B11-14] Design of high-efficiency grating couplers for suspended SiC nanobeams

〇Heungjoon Kim¹, Kap-Joon Kim¹, Byung-Seok Choi¹, Bong-Shik Song², Susumu Noda^3,4 (1.ETRI, 2.Sungkyunkwan Univ., 3.Kyoto Univ., 4.KUIAS)

Keywords:

Gratings,Nanobeams,SiC

In this work, we design an efficient grating coupler for suspended SiC nanobeams with a triangular cross-section. The grating consists of periodic rectangular rods placed on top of the nanobeam. Using 3D FDTD simulations, we show that the guided mode in the nanobeam is coupled into the upper free space by the grating coupler. By comparing eigenmode expansion and far-field analysis, we confirm that the diffraction mechanism of the grating coupler follows the Bragg phase-matching condition. Furthermore, by optimizing the grating geometry, we achieve a collection efficiency of up to 70% into the upper free space within a numerical aperture of 0.9, significantly exceeding previously reported values.