Numerical simulation of all-optical logic functions at micrometer scale by using plasmonic Metal-Insulator-Metal (MIM) waveguides

Abstract

All-optical integrated circuits are quite useful in the regime of ultrafast computing to overcome the limitations of existing electronic components. In this work, we have modelled two different all-optical integrated circuits to validate the operations of OR, AND, NOR, XOR, XNOR logic gates and half-adder circuit. To cascade the integrated circuits, a plasmonic metal–insulator-metal (MIM) waveguide based Mach-Zehnder interferometer (MZI) has been used. The signal switching is attained by using MEH-PPV [poly(2-methoxy-5-(28-ethylhexyloxy)-PPV)] as nonlinear Kerr material in one linear arm of MZI. The relative linear permittivity, response time and RI of nonlinear Kerr material are 2.7225, 2.0 e−15 s, and 1.67, respectively. The switching of signal across the output ports of MZI depends on the principle of self-phase and cross-phase modulation, which depends on the power of input signals. Signal power of 0.326 W/µm and 0.828 W/µm is used for low and high intensity which corresponds to logic level ‘0′ and ‘1′, respectively. The projected integrated circuits are analyzed at the wavelength of 1550 nm with transverse magnetic (TM) polarization under the contour of perfect matched layer (PML) as boundary conditions. The results conclude that the extinction ratio (ER) of single MZI is gradually decreasing with respect to the increase in power difference. For proposed design of single MZI the attained value of ER is 24 dB at the power difference of 0.3 dB. The authentication of proposed integrated circuits is done by using finite difference time domain (FDTD) based method.