Minimisation of thermally induced microbending losses in dual-coated optical fibres caused by viscoelastic behaviour of commercial polymeric coatings

The viscoelastic behaviour of commercial polymeric coatings for optical fibres is measured at room temperature using dynamic mechanic analysis, and the relationship between strain and stress in polymeric coatings is obtained. The thermally induced viscoelastic stresses in dual-coated optical fibres are derived from the viscoelastic behaviour of commercial polymeric coatings. The compressive radial stress on the glass fibre surface produces microbending losses, which can be diminished by properly choosing the thickness and material properties of polymeric coatings. The design of dual-coated optical fibres to diminish thermally induced microbending losses caused by viscoelastic behaviour of polymeric coatings is proposed. The thermally induced microbending loss in dual-coated optical fibres evaluated by Maxwell model is underestimated.