Integrated scalable hybrid spatial-spectral switch based on a bandpass ring-assisted asymmetric Mach–Zehnder interferometer

Photonic integrated switches with simultaneous space and wavelength selectivity represent a transformative technology for high-throughput data-center interconnection and scalable quantum networking. Silicon-based integrated switches are particularly compelling due to their ultra-compact footprints and high-density integration capabilities. However, achieving scalable non-blocking operation remains challenging because of interconnect-driven footprint expansion that grows rapidly with system size. While conventional hybrid spatial-spectral switches (HSSs) can reduce individual unit dimensions, they require M N (2 log 2 N −1)/2 switching elements for an N × N × M λ configuration, creating a fundamental scalability bottleneck. To address this limitation, we propose and experimentally demonstrate a novel HSS architecture based on bandpass ring-assisted asymmetric Mach–Zehnder interferometers (RAMZIs) with a 3 dB bandwidth of 1.54 nm. Implemented on a silicon-on-insulator (SOI) platform, we realize a compact 4×4×2 λ HSS using only six such elements (versus 12 in a conventional design), occupying a footprint of just 0.38 mm 2 while supporting data transmission rates exceeding 8×30 Gb /s. Crucially, the architecture can be further extended to N × N × M λ configurations with an efficient scaling factor of N ( M log 2 N −1)/2. To our knowledge, this work delivers the most compact spatial-spectral switching system demonstrated to date, establishing a new benchmark for both scalability and efficiency in optical switching. These advances open pathways toward large-scale, high-performance switching solutions essential for next-generation data centers and quantum communication networks.