Localized topological states in Bragg multihelicoidal fibers with a twist defect in the presence of a spacer

We have studied the influence of a spacer in a multihelicoidal Bragg fiber with a twist defect on the emerging of localized topological states. We have shown that if such a fiber is excited with a Gaussian beam this leads to the appearance of a defect-localized mode, whose topological charge coincides with the order of rotational symmetry of the fiber's refractive index distribution. The influence of the spacer on this mode is studied. (paper)