Birefringence evaluation of helically wound optical fibres

A simple, non-destructive method is presented for the characterization of t he birefringence properties of a helically wound mono-mode optical fibre. I t is shown that the Jones matrix model developed by J.N. Ross can be applie d to describe them, if the polarization evolution of light is measured with respect to a local reference frame (Serret-Frenet frame). In this case the Ross model is equal to the matrix model developed by R.C. Jones for a twis ted crystal. In order to use a fixed reference frame (laboratory reference frame) it is necessary to consider the rotation of the reference frame at t he fibre input face produced by the fibre topology. The orientation of the helical fibre axes at the input is defined following the geometrical criter ia proposed by Ross. The use of Poincare's method and Mueller calculus to r ewrite the Ross model simplifies the physical interpretation of the results . The method presented provides an easy way to measure the total linear ret ardation induced by the fibre curvature, and to separate the circular retar dation associated with the photo-elastic response of the fibre, from the to pological rotation of the reference frame defined only by the geometry of t he helically wound fibre.