Design of an optical NOR logic gate with high contrast ratio based triangular-lattice

The NOR gate is widely used in digital circuits and acts as a fundamental component in logic circuits. In this study, we propose an all-optical logic NOR gate based on two-dimensional photonic crystals, which employs linear interference and a ring resonator. Specifically, the proposed structure adopts a two-dimensional triangular lattice photonic crystal with silicon columns and has a resonant wavelength of 1540 nm. By combining the Plane Wave Expansion Method with the Finite-Difference Time-Domain method, we simulate and analyze the characteristics of the proposed NOR gate. The results show that the NOR gate achieves a minimum contrast ratio of 7.72 dB, a response time of 0.273 ps, and a calculated bit rate of approximately 797.4 GHz. Due to its simple structure and compact dimension (9.135 μm × 9.135 μm), the proposed design is well-suited for all-optical photonic integration.