Abstract

Nowadays there is a great interest in studying the properties of the cladding of standard single mode optical fibres (G.652) which are commonly used inside optical communication systems. This kind of study is important to understand the propagation properties of an optical signal along the cladding of a fibre which can lead to new applications either in the telecommunication or in the sensor fields. In order to analyse the optical behaviour of the cladding, in this contribution, photoelastic measures are presented, realized by means an experimental tomographic set-up, shown in Fig. 1, useful to measure fibre birefringence. Birefringence depends especially on the frozen internal stress that is generated during the drawing process. In an optical fibre the two zones of core and cladding present different values and signs (tension and compression) of stress because of their different physical properties. Photoelastic tomography is an appropriate method in measuring the stress distribution over an optical fibre section [1], A collimated laser beam crosses the fibre and the projections of the phase retardation between its polarization components, respectively parallel and perpendicular with respect to the fibre axis z, are measured along the transverse direction t. at different angles θ.

© 2007 IEEE