Modal bifurcation in chiral multilayered fibers

Abstract

In this paper, we investigate the modal bifurcation in chiral multilayered fibers through an approach of rigorous modal theory. The mirror symmetry of this theory is presented to provide physical insights into the modal bifurcation. The modes that are double degenerate and mirror images originally in achiral fibers are bifurcated by the chirality in chiral fibers. The modal bifurcation in chiral Bragg fibers is examined as an application of the theory. General guidelines of designing chiral Bragg fibers to possess circular polarization selectivity and wavelength selectivity are proposed from physical considerations and verified by numerical calculations.

Orbital angular momentum modes in dielectrically chiral-core fibers

“…For some fixed fiber structure the mode analysis is very important in order to understand the basic properties of propagation in the wave guide. So, we perform mode analysis in order to search for the guided modes using matured techniques [29,31,34]. Once the analysis has been carried out, one gets many modes including the OAM modes with phase distributions, intensity distributions, effective mode indices, circular birefringence (CB), and fraction of modal power in the core.…”

“…Notice that so far for OAM generation, the reported fibers are almost made of achiral media or with structural chirality. In fact, depending on the relationship between the size of chiral structures and optical wavelength, there are two kinds of practical fibers involving chirality: structurally chiral fibers [25][26][27][28] and dielectrically chiral fibers [29][30][31][32][33][34]. In the former, the characteristic length scale of the chiral structures is larger than or comparable to the wavelength of interest, while in the latter, the constituting materials are partly or entirely replaced by chiral media.…”

“…Even though the concept of dielectrically chiral fibers seems like an old topic, the idea of generating OAM modes in such kinds of fibers is still not investigated. Very few works exist that consider the use of dielectric chirality and the notable reports are on modal bifurcation in chiral multilayered fibers [29], guided modes in chiral fibers [31], and circularly polarized guided modes in dielectrically chiral photonic crystal fibers [30]. Additionally, a recent study highlighting the guiding of vortex modes in a cylindrical chiral-graphenedielectric waveguide structure under the influence of the chiral parameter and the Fermi level of graphene with the analysis of the intensity, phase, and polarization has been reported [35].…”

Modal loss in hollow-core Bragg fibers with a complete-band-gap chiral cladding

“…2. The modal analysis of air core air surrounding chiral cladding, stacked by medium 1, medium 2, 1, 2,... such fibers could be carried out based on the analytical formulation developed in a previous paper [4] published by us. We set the core radius to be 10λ , where the value of wavelength λ corresponds to point A in Fig.…”