Broadband three-dimensional multi-beam splitter enabled by quasi-parallel scanning

On-chip photonic systems are essential for next-generation information processing, where multi-way beam splitting can significantly enhance parallelism and processing capacity. Conventional splitters suffer from polarization and wavelength dependence, limited integration density, and poor uniformity. Here, we develop a femtosecond-laser-based quasi-parallel scanning technique to fabricate 3D multi-way splitters with high uniformity (up to 92.62%) and broad bandwidth (750-1050 nm). This approach offers a promising solution for future optical computing, sensing, on-chip communication, and quantum photonic systems.