Ultrafast all-optical half-adder and half-subtractor based on linear 2D photonic crystal

摘要

This paper had designed and simulated new structures for realizing half-adder and half-subtractor based on a linear photonic crystal. For this purpose, first, some individual gates such as AND and XOR are proposed, and then by combining these gates in a single structure a half- adder and half-subtractor are performed. All the simulations are performed with the finite difference time domain (FDTD) method. The transient analysis of the structures shows that the response time of the proposed half-adder and half-subtractor are 0.27 ps and 0.19 ps, respectively. The total footprint of the final structures is also as little as 90.3 μm~2 and the contrast ratio in a worse case is7.2 dB. The simulation results demonstrate the new structures have a considerably small size, ultrafast response time, and suitable contrast ratio in comparison with some previous works. Having these features make the introduced devices really usable for integration in the ultrafast optical integrated circuits.