Achievement of broadband uniform modal birefrigence in an index-guiding holey fibre using a novel circular hollow ring defect structure

A novel silica index-guiding holey fibre (IGHF) design is proposed utilizing a new defect structure that is composed of a three-layered defect with a central air hole germanosilicate ring and silica clad, based on a hollow optical fibre (HOF). Effects of these parameters on birefringence were numerically analysed using the plane wave expansion method. The proposed IGHF showed unique modal properties such as uniform birefringence and differential group delay in 1.55 νm optical communication windows that have not been achieved in prior arts.