  The effect of boundary deformation on the non-separable entanglement which
appears in the classical elec- tromagnetic field is considered. A quantum
chaotic billiard geometry is used to explore the influence of a mechanical
modification of the optical fiber cross-sectional geometry on the production of
non-separable entan- glement within classical fields. For the experimental
realization of our idea, we propose an optical fiber with a cross section that
belongs to the family of Robnik chaotic billiards. Our results show that a
modification of the fiber geometry from a regular to a chaotic regime can
enhance the transverse mode entanglement. Our proposal can be realized in a
very simple experimental set-up which consists of a specially designed optical
fiber where non-entangled light enters at the input end and entangled light
propagates out at the output end after interacting with a fiber boundary that
is known to generate chaotic behavior.
