Modeling Dual-SiO<sub>x</sub>N Thin-Film Edge Coupler with Ultra-Low Loss and Large Alignment Tolerance

High-performance facet couplers are essential components in the field of silicon nitride integrated photonic chips. In this work, a novel end-face coupling structure, using a double-layer SiO<sub>x</sub>N thin-film waveguide, is proposed. By precisely controlling the thickness and gap of...

Full description

Saved in:
Bibliographic Details
Main Authors: Zhaozhen Chen, Xin Fu, Lei Zhang, Zhengsheng Han
Format: Article
Language:English
Published: MDPI AG 2025-02-01
Series:Photonics
Subjects:
Online Access:https://www.mdpi.com/2304-6732/12/2/136
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:High-performance facet couplers are essential components in the field of silicon nitride integrated photonic chips. In this work, a novel end-face coupling structure, using a double-layer SiO<sub>x</sub>N thin-film waveguide, is proposed. By precisely controlling the thickness and gap of the SiO<sub>x</sub>N layers, we achieve flexible tuning of the output mode field size. This structure offers exceptional performance, including ultra-low coupling loss (TE: 0.29 dB, TM: 0.31 dB), large 3 dB alignment tolerance (±2.5 μm), and near-zero polarization-dependent loss. The optimized design strikes a favorable balance between coupling efficiency and alignment tolerance, making it well-suited for a wide range of photonic applications.
ISSN:2304-6732