All-optical NOR gate based on cross structures in 2D photonic crystal using logic NOT and OR gates

An optical NOR gate is presented based on two different cross waveguide structures in 2D photonic crystal. The two different cross waveguide structures are logic NOT and OR gates. The layouts of logic NOT and OR gates are simulated and analyzed individually using the finite difference time domain method. The structure is optimized by an iterative process. The contrast ratio for the logic NOT gate is 11.605 dB and for the OR gate is 22.113 dB. The size of the NOT and OR structures is 10 x 10 mu m. With the optimized parameters, both the gates are combined without using any external device to design the NOR gate. The operation of the NOR gate is numerically demonstrated using an FDTD simulation. The contrast ratio is 15.97 dB for the NOR gate. Since nonlinear material is not used, the power consumption is lower. This NOR structure has an operating bandwidth of 40 nm. Thus, it is favorable for use in optical communication systems and optical signal processors. (C) 2018 Optical Society of America