All-optical NOT, OR, and XOR Logic Gates Using Silicon Slot Waveguides

All-optical NOT, OR, and Exclusive OR(XOR) logic gates utilizing silicon slot waveguides are proposed and numerically analyzed in this work. The structure has a silicon slab with slot regions such as two input waveguides and square cavity resonators and one output waveguide. The optical spectra of the designed structures are attained with the method of finite difference time domain. The all-optical logic gate features of the design are achieved by applying optical signals with 00 or 1800 phase differences from the input ports. Basic parameters such as transmission spectrum (T), modulation depth (MD), and contrast ratio (CR) are performed to show the optical features and ability of the proposed logic gates. The threshold transmission limit is 1.7% to define the status of the output ports as ON or OFF. At 689.5 nm, the maximum transmission, modulation depth, and contrast ratio are 149%, 97%, and 15.36 dB, respectively.