Modelling birefringence in isolated elliptical core photonic crystal fibers

A simple model for calculation of the birefringence in asymmetric isolated core PCFs employing approximation with an ellipsoid suspended in air is presented. Birefringence values in the order of 10/sup -2/ are obtained and comparison with both calculations based on a SEM picture of a real fiber and measurements performed on the same fiber are presented. In both cases good agreement is observed.