Study of a MOEMS XOR gate based on optical ring resonator

Abstract

Based on ring resonator with Microelectromechanical systems, optical XOR logic gate is proposed in this paper to realize the optical logic gate application. The proposed gate is basically structured on an optical ring resonator with 7 μm radius and resonance wavelength of 1.55 μm which is placed on the edge of a thin SiC circular diaphragm. In order to apply input voltages to electrodes, two very thin circular gold layers with 50nm air gap spacing are deposited under the diaphragm. Input voltages are considered as logic inputs and resonance wavelength shift as logic output. When an input DC voltage is applied across the diaphragm, an attractive electrostatic force is created between two electrodes. As a result, the diaphragm is deformed and an internal stress is created. This in turn changes the resonator refractive index due to the photoelastic effect and thus shifts its resonance wavelength about 35nm. COMSOL Multiphysics and MATLAB are carried out to verify FEA and numerical analysis of the designed structure, respectively. A good agreement between the simulations and analytical results is obtained. Enhancement of the wavelength shift and FSR are resulted. The proposed structure is used as an optical XOR gate for the first time.