Scalable all-optical logic gates using cascadable silicon photonic resonator inverter

All-optical logic gates are a promising solution for overcoming the speed, bandwidth, and power limitations of electronic computing architectures. This paper reports a compact, fully passive, and CMOS-compatible all-optical logic platform based on cascadable silicon photonic ring resonator inverters. Logic inversion is achieved through engineered optical interference between coupled microring resonators sharing a common bus waveguide, without the use of electro-optic or thermo-optic tuning. The proposed inverter preserves signal contrast and optical power levels, enabling direct cascading and forming a scalable foundation for higher-order photonic logic circuits. Using this inverter as a universal building block, NAND and NOR gates are realized through hierarchical interconnection. Full-wave electromagnetic simulations validate the operating principle and cascadability, and fabricated devices on a 220 nm silicon-on-insulator platform confirm fabrication feasibility and CMOS compatibility. This architecture provides a viable route toward dense, low-power, and high-speed photonic logic for optical computing, neuromorphic photonics, and AI-accelerated hardware systems.