Patterned overlays: Thin silicon layer applied to glass waveguides
The modifications to the optical properties of a slab waveguide coated with a patterned thin high dielectric overlay layer are examined. The asymmetric nature of the entire waveguide configuration makes it possible to keep the waveguide mode highly confined in the slab waveguide while enhancing the evanescent wave-overlay interaction. The sensitivity of the guided light to variations in the refractive index, thickness, period, and length of patterned overlay are examined using Finite Difference Time Domain (FDTD) simulations. For various waveguide geometries, transmission and reflection spectrums are obtained from which active and passive optical device configurations are explored.