Designing ultra-fast all-optical full-subtractor using the photonic crystal structure

In this paper, a photonic crystal-based structure for an all-optical full-subtractor has been proposed. The structure includes six nonlinear resonant rings to transmit the incoming optical waves toward the output ports. Using the different radii for nonlinear rods made the possibility of the dropping operation for different amounts of optical intensities. The nonlinear rods are made of a doped-glass with an optical Kerr coefficient of 10–15 m2/W. To calculate the components of the optical waves throughout the structure, the finite-difference time-domain method has been used. The simulation results prove the correct functionality of the proposed structure. Besides, the maximum rise time of the device is equal to 2 ps. The contrast ratio and the area of the structure are around 8.08 dB and 2790 µm2, respectively.