Highly Birefringent Photonic Crystal Fibre with Enhanced Sensitivity to Hydrostatic Pressure

We present three constructions of birefringent photonic crystal fibres with increased sensitivity to hydrostatic pressure. The enhancement of sensitivity was obtained by enlarging diameters of several cladding air-holes or by introducing two air channels located symmetrically in the solid part of the cladding. We used nodal based finite elements method to calculate pressure-induced deformations and stress distribution in the fiber cross-section and hybrid edge/nodal finite elements method with perfectly matched layer to calculate propagation constants of the fiber modes. We calculated the spectral dependence of the phase modal birefringence and its susceptibility to hydrostatic pressure. Our results show that the sensitivity to pressure can be increased several times by optimizing the fiber geometry