Optical Coupling Enhancement Of Slot Waveguide

The development of the modern optical devices trends to be integrated and high speed. The slot waveguides attracted greatly interest of the scientist due to its properties of the high confinement and high intensity. The slot waveguides have a diverse range of applications, such as sensors, opto-mechanical device actuation and nanophotonic devices.Firstly, the paper investigates the properties of the surface plasmon polaritons. The optical transmission properties of the slot waveguide and the V-groove waveguide are studied based on the Finite-difference time-domain method and the metal dispersion model at light wave band which are presented in the paper. A method of improving the optical confinement in the optical waveguide is presented, and explain the theory of the optical coupling enhancement of the metallic gratings. The electric field enhancement of traditional silicon slot waveguide is significant, however the magnetic field in the slot region is not enhanced. Both of the electric field and the magnetic field in the slot with metallic gratings are greatly enhanced. The dependence of the electric field enhancement on the width of the metal gap and the wavelength is systematically studied, and the result shows that the electric field enhancement factor gets the strongest when the gap width is about 0.01 times of the wavelength and the mechanism of the enhancement is theoretically analyzed. The transmission of the slot waveguide with vertical metallic gratings is investigated, and the results show that, as the slot size and the width of the metal gap increases, the electric field enhancement decreases and trends to be stabilized.The transmission of a V-groove slot waveguide based on the slot waveguide with two parallel nanowires is studied. The metallic gratings for the electric and magnetic field in the slot has significant effect due to the surface plasmon polaritons in the gratings, which result in a decrease of the effective refractive index in the slot, and enhances the optical coupling of the waveguide. The results show that the metallic gratings can be applied to other optical waveguide, and provide a reference for designing high confinement optical waveguide.