FDTD Investigation of Efficient and Robust Integration Between Si3N4 and Ge-Rich GeSi for Waveguide-Integrated Electro-Absorption Optical Modulators

Natdanai Khongpetch; Worawat Traiwattanapong; Surasak Chiangga; Pichet Limsuwan; Papichaya Chaisakul

doi:10.1109/access.2023.3249102

FDTD Investigation of Efficient and Robust Integration Between Si3N4 and Ge-Rich GeSi for Waveguide-Integrated Electro-Absorption Optical Modulators

Date

2023-01-01

Authors

Natdanai Khongpetch

Worawat Traiwattanapong

Surasak Chiangga

Pichet Limsuwan

Papichaya Chaisakul

Abstract

Si 3 N 4 photonic integrated circuits have gain significant and rapid interest in different photonic applications thanks to its superior passive performance. Nevertheless, optical integration between Si 3 N 4 and Ge-based optical components remains critically challenging especially for optical modulation. In this paper, via 3D-FDTD calculations we investigate the optical integration between Si 3 N 4 and Ge-based waveguides using vertical coupling configuration employing amorphous Si (α-Si) as an optical bridge showing efficient and robust coupling efficiency, which can be maintained according to the tolerant analysis with respect to the variations in optical wavelengths and critical parameters of the coupling structure. In addition, with respect to the recent theoretically-optimized SOI waveguide-integrated Ge-based optical modulators, we found that the studied coupling structure could be employed to enable a low-voltage Si 3 N 4 waveguide-integrated Ge-based optical modulator with a competitive extinction ratio/insertion loss performance, increasing the prospect of Si 3 N 4 -based photonic integrated circuits for low-energy optical interconnects.