Air- and water-core integrated optical waveguides

Hollow-core integrated optical waveguides enable quasi-confinement of light into the hollow-core, hence offer intense interaction between light and gas or liquid filled into the core on one hand and prospective for integration of various components (not only photonic components, but also micro-fluidic and MEMS components) in a chip scale on the other hand. These structures are interesting for sensing applications, as well as spectroscopy, light-driven biological/chemical processes, or non-linear optics of gas/liquids. However, obtaining a low-loss hollow-core integrated optical waveguide with rectangular core cross-sectional shape is not easy. In this presentation, the role of cladding bilayer material compositions to obtain low-loss air- and water-core integrated optical waveguides is discussed. Using the simple Fresnel reflection formulae, the optimal material composition was determined. Structures that exhibit very low leakage loss for quasi-TE00 mode, designed using Si-compatible materials by taking into account the material composition aspects were proposed. An iterative procedure using a semivectorial effective-index-method leaky mode solver has been employed in calculating the bilayer thicknesses, while a finite-element vectorial leaky mode solver was used to verify the results.