Photonic bandgap confinement in an all-solid tellurite glass photonic crystal fiber

Abstract

We report on the fabrication and optical assessment of an all-solid tellurite-glass photonic bandgap fiber. The manufacturing process via a preform drawing approach and the fiber characterization procedures are described and discussed. The fiber exhibits some minor morphological deformations that do not prevent the observation of optical confinement within the fiber by bandgap effects. The experimental fiber attenuation spectrum displays clear bandgap confinement regions whose positions are confirmed by modeling the guiding properties of the ideal geometry using a plane-wave expansion method. The model identifies the bound modes of the structure and provides confirmation of experimentally observed mode field profiles.

Effect of submicron deformations on the transmission of all-solid photonic bandgap fibre

“…High purity tellurite glasses, with dB/km losses (Hill and Jha, 2007), and chalcogenide glass fibres, with losses as low as dB/km (Snopatin et al, 2009), can be produced. However, the experimental losses in non-silica PBFs are still significantly higher than the intrinsic material losses (Schmidt et al, 2009;Ren et al, 2013;Saitoh et al, 2014;Lousteau et al, 2012;Caillaud et al, 2014). The increased loss in the high-transmission windows may be related to the scattering at the interfaces due to the formation of crystallites by glass devitrification (Schmidt et al, 2009) or to the formation of air bubbles in the fibre preform (Brilland et al, 2008).…”

“…With collapsed interstitials holes the transmission of all the fibres was greater than 20 dB/m. All-solid tellurite-glass photonic crystal fibre had experimentally measured transmission losses of around 50 dB/m (Lousteau et al, 2012). For chalcogenide glass PBF, (Caillaud et al, 2014) measured losses in the 20-50 dB/m range at a wavelength of 3.39 μm.…”

“…During drawdown of glass-air micro-structured optical fibres, a range of hole deformation patterns can occur (Xue et al, 2006), including hole collapse, hole expansion, hole enlargement and hole shape changes. All-solid PBFs are more robust towards structural deformations; however, unwanted structure changes can also be found (Brilland et al, 2008;Lousteau et al, 2012;Caillaud et al, 2014). Transversal defects due to the fabrication process enhance field tunnelling through the PBG into the outer cladding.…”

“…For the PBF fibre considered, the deformation of the transverse structure leads mainly to a narrowing of transmission bands. To reveal the possible source of large experimental losses observed in a real all-solid PBF (Lousteau et al, 2012), a submicron longitudinal variation of the fibre geometry was studied. Fig.…”

“…Fig. 1a shows the transverse structure of the experimental fibre considered (Lousteau et al, 2012). The fibre consists of highrefractive index micro-sized rods packed into a hexagonal lattice.…”