Analytical Framework for Mode-Coupling in Hollow-Core Inhibited-Coupling Fibers

We present an analytical framework based on Coupled Mode Theory to model mode coupling in Hollow-Core Inhibited-Coupling Photonic Crystal Fibers. The derived expressions accurately quantify the coupling between core and cladding modes, enabling precise predictions of attenuation and dispersion. Our results reveal that the coupling regime, determined by the interplay between the loss difference and the propagation constant mismatch of the independent modes, plays a critical role in shaping these parameters. Strong agreement between the analytical predictions and numerical simulations validates the model's reliability. For the first time, an analytical model is successfully developed to predict and interpret numerical results, providing a robust tool for advancing the understanding of the inhibited coupling guidance mechanism and optimizing fiber design.