Geometrical Deformation Effects on Loss and Modal Content in Hollow-Core Tube-Lattice Fibers

In this work, we numerically investigate the effects of geometrical deformations due to the fabrication process on propagation loss of the fundamental mode (FM) and modal content in Hollow-Core Tube-Lattice Fibres (HC-TLFs). HC-TLFs are gaining more and more ground in applications (high power beam delivery [1], low latency communications [2], gas-optics [3], and quantum optics [4]) requiring low propagation loss, single-mode operation, and high quality and polarization purity of the propagating light. In the last year, thanks to an intense research activity, these requirements have been fulfilled, at least for ideal geometries. Experimental results show there is still a gap between ideal and measured performance, due to non-idealities introduced by the fabrication process, in particular geometry deformations and silica surface roughness.