Design and analysis of photonic crystals based all optical Feynman gate

In this work, we propose a novel design and numerically analyzed an all-optical reversible logic Feynman gate based on two-dimensional (2D) photonic crystal structures. It uses no nonlinearity (Kerr effect, gain modulation etc.) for its operation and therefore does not require separate switching signals or pump to activate the switching. In other words, it is a passive device and performs at ultrahigh speed of more than 3 Tb/s. Research in photonic crystal based RLG without using nonlinearity, and reference light is an important field to explore. Finite-difference time-domain (FDTD) simulations confirm that the proposed structure supports high-contrast logic operations at telecommunication wavelengths 1.55 µm and minimal power loss. The structural design of the all-optical Feynman gate is very simple and hence demonstrates potential for integration in future optical computing and quantum information processing systems. The gate shows high contrast ratio (17.92 dB and 16.91 dB for two outputs), compact footprint area (97.3 µm²), and ultrafast speed (3.33 Tb/s) which are optimized by changing the wavelength of light, refractive index of silicon rods, and defect radii.