In this work two-beam, multiple-beam and manual variable wavelength (VAWI) interferometric techniques were applied to study the dispersion properties and structural deformation of polymer fibres. These techniques are used to measure the refractive indices, refractive index profiles and birefringence for deformed and un-deformed fibres. The fibre drawing devices attached with interference microscopes and systems are used to investigate and detect various types of deformations associated with stretched polymer fibres.