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arXiv · 2604.12566

Scalable 3D silicon nitride photonic interposer for high-density optical interconnects

Yu Xia·Yuhao Huang·Yuemin Li·Jie Wang·Yunqi Fu·Yaoran Huang·Hongjie Liang·Hao Fang·Zheng Li·Mingfei Liu·Yitian Tong·Di Yu·Chao Xiang
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Abstract

Modern computing workloads demand energy-efficient, high-bandwidth interconnects, motivating photonic interposers as an alternative to electrical links. Here we demonstrate a compact 3D silicon nitride (SiN) photonic interposer prototype comprising two routing layers, with the 3D routing scheme optimized by a global optimization algorithm. The 3D interposer realizes a fully connected 12-node optical network that reduces the total number of intralayer crossings from 495 for all-planar routing to merely 150 (69.7% reduction), below the theoretical lower bound of 153 for all-planar interconnects. Comparing the two schemes, our 3D design achieves a 45.8% reduction experimentally in the average loss per waveguide. The proposed 3D routing architecture also features inherent symmetry and is scalable to higher node counts, flexible node placements, additional routing layers, and other operating wavelengths, enabling denser, lower-loss photonic interposers for next-generation scale-up and high-performance computing (HPC) systems.

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Yu Xia, Yuhao Huang, Yuemin Li, Jie Wang, Yunqi Fu, Yaoran Huang, Hongjie Liang, Hao Fang, Zheng Li, Mingfei Liu, Yitian Tong, Di Yu, Chao Xiang. 2026-04-14. Scalable 3D silicon nitride photonic interposer for high-density optical interconnects. https://arxiv.org/abs/2604.12566

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