Asymptotic Modelling of a Six-Hole MOF

Abstract

Abstract-We model the drawing of a six-hole microstructured optical fibre with a combination of asymptotic techniques and a new efficient numerical method, and compare this to a previous set of experiments and finite element simulations. The new approach accurately models the deformation of the inner channels and predicts cross-sectional fibre geometries which are a better match to the experiments than the previous, more computationally expensive simulation technique.

A two-dimensional asymptotic model for capillary collapse

“…For a radial length scale that is much smaller than the axial length scale, as assumed by Klupsch & Pan, the asymptotic fibre-drawing model of Stokes et al (2014Stokes et al ( , 2019) may be used for capillary collapse and yields analytic formulae relating the extent of collapse to the harmonic mean of the viscosity and the surface tension of the glass. The accuracy of this model is excellent for drawing of fibre from very slender preforms (Chen et al 2016b) and is expected to be excellent for capillary collapse which does not see the high draw ratios and sharp tapers seen in fibre drawing and which are known to cause discrepancies between models and experiments, especially when the radius of the preform is not sufficiently small relative to the neck-down length (Chen et al 2016a).…”

“…2015 a , b ; Chen et al. 2016 b ; Stokes, Wylie & Chen 2019), and the drawing of slender axisymmetric tubes is a particular case. Thus, 2-D models exist which are applicable to capillary collapse and which predate that of Klupsch & Pan (2017).…”

“…The accuracy of this model is excellent for drawing of fibre from very slender preforms (Chen et al. 2016 b ) and is expected to be excellent for capillary collapse which does not see the high draw ratios and sharp tapers seen in fibre drawing and which are known to cause discrepancies between models and experiments, especially when the radius of the preform is not sufficiently small relative to the neck-down length (Chen et al. 2016 a ).…”

“…it is fibre drawing with unit draw ratio. Extensive attention has been given over three decades to mathematical modelling of the drawing of slender microstructured optical fibres, incorporating both axial and cross-sectional flow (Yarin et al 1989;Yarin, Gospodinov & Rusinov 1994;Fitt et al 2002;Griffiths & Howell 2008;Stokes et al 2014;Chen et al 2015;Xue et al 2015a,b;Chen et al 2016b;Stokes, Wylie & Chen 2019), and the drawing of slender axisymmetric tubes is a particular case. Thus, 2-D models exist which are applicable to capillary collapse and which predate that of Klupsch & Pan (2017).…”

Stability of drawing of microstructured optical fibres

“…The asymptotic techniques applied in studies of this type have been shown to be accurate by Chen et al. (2016). All of these studies were focused on the steady states and did not consider the stability problem for the drawing of non-axisymmetric threads.…”