A miniature design of binary subtractor using 2-D photonic crystal structure for high-speed applications

The expansion of the digital market is accelerating, and for faster communication, optical technologies have been developed. The binary subtractor is a combinational circuit that can compute the subtraction operations in arithmetic logic unit (ALU). The desired design is depicted as a 2-D structure with two T-shaped waveguides, and it is operates at a wavelength of 1550 nm. The design is verified and analyzed using finite-difference-timedomain (FDTD) method. It is also verified using MATLAB software. The identical design has been computed and simulated numerous times in this work, but with different lattice constants, refractive indices, and silicon rod radii. In this study, photonic crystals are used to construct a binary subtractor that is both compact and capable of producing a high contrast ratio (5.185 dB for difference and 17.78 dB for borrow). Moreover, the transmission efficiency is achieved 89.3%, insertion loss is 0.49 dB, and the response time and bit rate are achieved by 0.0204 Ps and 49.01 Tbps respectively.