The presentation will focus on the specialty hollow-core fiber with novel designs, and investigation of their linear properties using finite-element method  and their nonlinear optical properties. Short pulse propagation in these fibres is modelled using a unidirectional field propagation equation. The possibility to easily tune the optical properties of the fibre by changing the filling material into hollow-core fiber is a great advantage that brings a large degree of freedom to designing the applications. It may lead to the development of optical sources with exceptional properties.