Are optical vortices robust in twisted fibres?

• Published in: Journal of optics (2010) 2012-08, Vol.14 (8), p.85702-1-6
• Main Author: Alexeyev, C N
• Format: Article
• Language: English
• Subjects: Anisotropy; Applied sciences; Charge; Current carriers; Exact sciences and technology; Fiber optics; Fibers; Fibres; Fluid flow; Fundamental areas of phenomenology (including applications); Optical telecommunications; optical vortex; Optics; Physics; Robustness; spun anisotropic fibres; spun elliptical fibres; Telecommunications; Telecommunications and information theory; Topology; Wave optics; Wave propagation, transmission and absorption
• ISSN: 2040-8978; 2040-8986
• DOI: 10.1088/2040-8978/14/8/085702

We study the question of robustness of optical vortices (OVs) in twisted anisotropic and elliptical fibres with respect to external perturbations which do not depend on the longitudinal coordinate. On the basis of the developed modification of the coupled mode theory we show that the topological charge carried by OVs in twisted elliptical and anisotropic fibres proves to be robust with respect to induced material anisotropy of the fibre. In contrast, OVs and the topological charge carried are unstable with respect to induced z-independent additional ellipticity of the transverse cross-section of the fibre. In this case OVs are found to invert their initial topological charge upon propagation. We also compare the robustness of OVs in twisted fibres with their robustness in ideal fibres.