2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/95584We describe a semi-analytical approach for three-dimensional analysis of photonic crystal fibre devices. The approach relies on modal transmission-line theory. We offer two examples illustrating the utilization of this approach in photonic crystal fibres: the verification of the coupling action in a photonic crystal fibre coupler and the modal reflectivity in a photonic crystal fibre distributed Bragg reflector.15 pages including 7 figures. Accepted for J. Opt. A: Pure Appl. OptOpticstext