A simplified route to manufacturing microstructured optical fibres*

Microstructured optical fibres (MOFs) are used widely in the communications industry for the transmission of data signals. They are typically constructed from glass via a drawing process and their resulting cross-sections comprising a complex array of holes and interconnecting glass 'struts'. But how do we make a MOF with a desired final cross-sectional configuration?  We present a model for the surface-tension-driven evolution of the viscous struts, or viscidas, and the connecting junctions, which bears similarities to  network models used for foam dynamics. A degeneracy in the model highlights the need for care when constructing the model. Crucially, the theory provides a simplified framework for predicting the evolution of a complex MOF cross-section during the drawing process. Moreover, the model is well-posed for inverse time, allowing us to predict the start configuration required to generate a desired final cross-sectional profile.