Considerations on material composition for low-loss hollow-core integrated optical waveguides

The role of cladding bilayer material compositions to obtain low-loss hollow-core integrated optical waveguides was studied. Using the simple Fresnel reflection formulae, the optimal material composition was determined. It is shown that using bilayers with higher index-contrast does not always lead to a lower loss for (quasi-)linearly polarized modes. Based on that knowledge, structures that exhibit very low leakage loss for quasi-TE00 mode are proposed and designed using Si-compatible materials.