Design and study of nano-plasmonic couplers using aluminium arsenide and alumina

A theoretical study of nano-plasmonic couplers constructed using aluminium arsenide (AlAs) and alumina (Al₂O₃) is presented. The analysis has been done using the finite difference time domain technique. The dependence of coupling efficiency on the width of the air layer of silver-air-silver waveguide has been investigated to determine the optimal width of air. Coupling efficiency with the variation in input signal wavelength, reflection coefficient and return loss have been calculated numerically in order to characterise the performance of AlAs and Al₂O₃ as nano-plasmonic couplers. The resonant peaks have also been obtained for both AlAs and Al₂O₃. The couplers provide appreciable performance at 1550 nm wavelength and have simple rectangular shape with no tapering which provides advantage in the fabrication process. It also offers broadband operation.