High-Contrast and High-Speed Optical Logic Operations Using Silicon Microring Resonators

Microring resonators, known for their compact size, wavelength selectivity, and high-quality factor, enable efficient light manipulation, making them ideal for photonic logic applications. This paper presents the design and simulation of seven fundamental all-optical logic gates-XOR, AND, OR, NOT, NOR, NAND, and XNOR-using a seven-microring silicon-on-silica waveguide. Operating at the standard telecommunication wavelength of 1.55 µm, the proposed design exploits constructive and destructive interferences caused by phase changes in the input optical beams to perform logic operations. Numerical simulations, conducted using Lumerical FDTD Solutions, validate the performance of the logic gates, with the contrast ratio (CR) as the primary evaluation metric. The proposed design achieves CR values of 14.04 dB for XOR, 15.14 dB for AND, 15.85 dB for OR, 13.42 dB for NOT, 12.02 dB for NOR, 12.75 dB for NAND, and 14.10 dB for XNOR, significantly higher than those reported in previous works. This results in a data rate of 199.8 Gb/s, facilitated by a compact waveguide size of 1.30 × 1.35 μm². These results highlight the potential of silicon photonics and microring resonators in enabling high-performance, energy-efficient, and densely integrated optical computing and communication systems.