Design of an optical half-adder based on two-dimensional photonic crystals using feedforward neural networks

The optical half-adder is one of the important components in the design of optical digital circuits. In this study, an optical half-adder based on two-dimensional photonic crystals with a square lattice has been designed, optimized, and simulated. A feedforward neural network model is used to achieve the optimal state by selecting the defect rod dimension and phase of the input laser to optimize the performance of the optical device. The results show that the proposed structure has an appropriate power difference in both high and low logic states, which results in fewer errors in detecting logical values at the outputs. Another feature of this structure is the use of a minimal number of defect rods and the absence of ring resonators, which leads to a reduction in size and propagation delay time of light in the structure. Moreover, due to its aforementioned features and small size, this structure is suitable for use in integrated optical circuits.