Interconnect elements propagation quantities in PIC

This paper describes methods to extract nominal values of propagation quantities for thin-film, straight interconnect elements. The propagation quantities like effective dielectric permittivity ɛ_eff, attenuation α, characteristic impedance Z_o are calculated with the use of analytical and approximated formulas. These expressions are obtained by transforming and by fitting formulas, typically used for calculation of per unit length transmission line parameters. Methods are verified for typical thin-film interconnect elements dimensions and for typical materials used in the Photonics Integrated Circuits (PIC). The novelty of the study is the parametrization with respect to the geometrical dimensions. The parametrization is based on the approximation expressions in the form of rational polynomials obtained by fitting.