Dresden 2026 – scientific programme
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DS: Fachverband Dünne Schichten
DS 20: Poster
DS 20.14: Poster
Thursday, March 12, 2026, 18:30–20:30, P2
Distributed Bragg Reflector-Enhanced Grating Coupler on SiON-Doped Silicon Platform for 905 nm Using Particle Swarm Optimization — •Metehan Ari1, Iremnur Duru1, Ali Karatutlu1,2, and Timuçin Emre Tabaru1 — 1Sivas University of Science and Technology — 2] Institute of Materials Science Nanotechnology and National Nanotechnology Research Center (UNAM) Bilkent University
A vertical grating coupler operating at 905 nm was designed on a silicon oxynitride-doped silicon (SiON-Si) platform for on-chip LiDAR. For the first time, the SiON-Si layer served as the core of a grating structure. The material exhibited a refractive index of 2.27, CMOS compatibility, and negligible two-photon absorption, with its electronic structure confirmed via soft X-ray absorption spectroscopy at the HESEB beamline (SESAME).
To enhance performance, a Distributed Bragg Reflector (DBR) consisting of three alternating SiON-Si/SiO* layers was integrated beneath the grating to suppress substrate leakage. Design optimization using Particle Swarm Optimization (PSO) and FDTD analysis demonstrated that the DBR increased coupling efficiency from ~35% to 53%. Consequently, the optimized device achieved 53% (-2.76 dB) efficiency for TM-polarized vertical coupling at 905 nm. Fabricating both the grating and waveguide within the same SiON-Si layer eliminated heterogeneous interfaces, maintained single-mode behavior, and validated the platform's potential for integrated photonic circuits.
Keywords: Grating coupler; SiON-doped silicon; Distributed Bragg reflector; LiDAR; Particle swarm optimization