A twist sensor based on polarization-maintaining fibers with different cladding diameters

Optimization of an all-optical three-input universal logic gate with an enhanced contrast ratio by exploiting a T-shaped photonic crystal waveguide

Universal gates (NAND and NOR) are used for any electronic circuit that is affordable and straightforward to build all logic gates (LoG). In this work, the T-shaped 2D photonic crystal (PhC) is exploited to design a three-input universal LoG premised on the beam-interference principle. The design criteria of pitch (a), rod radius (r), and refractive index (n) are employed to obtain a high impact output. The methodologies of plane wave expansion and finite-difference time-domain are employed for examining the framework of universal LoG at 1550 nm wavelengths (λ). The suggested universal LoG design has a compact size of 8.4µm×4.8µm. Additionally, the structure yields a high contrast ratio (CR) of 20.37 dB for the NAND LoG and 28.45 dB for the NOR LoG, and maximum transmission efficiency of 50.6% and 70% for the NAND and NOR gates; correspondingly, the best and worst three-input NAND gate response times are 19.5 ps and 21.4 ps. Similarly, the response time of the three-input NOR gate is 26 ps. The proposed universal gate's primary goal is to offer a high CR and a compact structure while being compatible with any other logic gate.