Improved design of all-optical photonic crystal logic gates using T-shaped waveguide

In this paper, we propose new structures of all-optical logic gates based on two-dimensional photonic crystal of square type lattice with Si rods in air background. The proposed structures are based on T-shaped waveguide with optimized edge rod radius. An extra reference input port is included in the structure along with the actual input ports required for a logic gate. The simulation results show that the proposed T-shape waveguide can work as a NOT gate and a dual T-shape waveguide can work as NOR, XNOR and NAND gate with proper change in the phase values of logic '1' input. The proposed structures have fast response time with value not more than 0.35 ps. The size of these structures is also small. It is expected that these new T-shaped structure based all-optical logic gates are suitable for large scale optical integration and can potentially be used in on-chip photonic integrated circuits.