Multifunctional and wavelength division multiplexing all-optical logic gates based on four-port metal-insulator-metal waveguides coupled with a ring resonator.

In the past few years, designing multifunctional all-optical logic devices has attracted more and more attention in integrated optical computing. We report a metal-insulator-metal based four-port all-optical logic gate device containing two parallel straight waveguides and a ring resonator. We employ the scattering matrix method to analyze the coupling mechanisms of the hybrid waveguide and adopt the finite-difference time-domain method to design four fundamental logic functions of AND, OR, XOR, and NOT based on the all-optical coherent control of the four-port system under three symmetrically incident conditions. We demonstrate that these logic functions can be freely modulated by changing the phase difference of the input light at two resonant wavelengths or in a broad band. The logic gate device proposed shows a simple structure with multiple functions, multiple channels, and convenience in fabrication, and can be applied in parallel optical computing based on wavelength division multiplexing technology.