Mathematical model of the spinning of microstructured fibres

Abstract

Abstract:We construct a fluid mechanics model of the drawing of microstructured optical fibres ('holey fibres'). This model can be used to understand and quantify methods for controlling the fibre geometry. The effects of preform rotation are included to examine methods for reducing fibre birefringence. Asymptotic numerical-solutions are obtained and applied to two typical microstructured-fibres and a number of practical suggestions are made for achieving sub-mm spin pitches without damaging the microstructure within.

Drawing of micro-structured fibres: circular and non-circular tubes

“…A mechanism sometimes used for control of the fibre draw process, that we have not yet considered and which remains for future investigation, is rotation of the fibre during drawing so that the resulting fibre has a twisted geometry (Voyce, Fitt & Monro 2004.…”

Mathematical Modeling as an Accurate Predictive Tool in Capillary and Microstructured Fiber Manufacture: The Effects of Preform Rotation

“…Further to the results of [9] and [10], the aims of this study are therefore to 1) confirm that preform rotation causes geometry change, to predict these changes and compare the predictions with experimental results and 2) to validate the mathematical model (described below) by carefully establishing all experimental variables, thus removing the need for fitting parameters. It is hoped that this will both increase the confidence held in mathematical modeling, promoting its continued development for complex MOF manufacture, and provide an accurate predictive tool to experimenters for certain classes of MOF (see [9] for a detailed discussion of how the mathematical model may be used to predict geometry changes in general classes of MOF).…”

“…In a previous study, we developed a mathematical model to examine the effects of preform rotation on capillary drawing [9]. While it may appear that a capillary tube is an unrealistic approximation of a complex microstructured fiber, for the two specific fiber-types described in [10] ("Type-one" fibers: large mode-area microstructured fibers with an approximately uniform distribution of diffuse holes in a cross section, and "Type-two fibers": fibers where a large jacket surrounds a microstructured region with a high density of holes in a cross section), the approximation is justified and thus the results of this paper may be directly applied to microstructured fiber preform spinning for certain classes of microstructured fiber structure (see [10] for details). Furthermore, we regard the model described here and detailed in [9] as an intermediate step towards modeling the fabrication of arbitrary MOFs.…”

“…0733-8724/$25.00 © 2008 IEEE There exist a number of studies of optical-fiber drawing, including studies related to the drawing of capillary tubes (see, for example, [9]- [14]). However, the desire to reduce fiber birefringence and PMD in microstructured fibers motivates an analysis that additionally includes the effects of preform rotation on drawn fibers.…”

“…The practical usefulness of mathematical modeling of this type can take several forms: 1) the identification of useful parameters (e.g., sensitivity parameters to determine stable drawing regimes; see [12]); 2) an increased understanding of the physics involved in the problem (see [10] and [13] for a predominantly qualitative discussion of the effects of preform rotation); and 3) accurate predictions of the appropriate choices of drawing parameters for given geometric requirements.…”