Polarimetric sensitivity to hydrostatic pressure and temperature in a side-hole fiber with squeezed microstructure

Abstract

We report on sensing characteristics of an endlessly single mode silica fiber with microstructure squeezed by very large side-holes. An elliptical shape of the cladding holes results in high phase and group modal birefringence, equal respectively to B = 3.33 × 10−4 and G = −6.62 × 10−4 at 1.55 μm. Thanks to a large diameter of the side-holes located in the solid part of the cladding, the fiber polarimetric sensitivity to hydrostatic pressure was increased two times compared to earlier reports and equals Kp = −25.6 rad MPa−1 m−1 at 1.55 μm. Moreover, the fiber has a very low polarimetric sensitivity to temperature KT = −9.18 × 10−3 rad K−1 m−1 at 1.55 μm, thus allowing for hydrostatic pressure measurements with little cross-sensitivity to temperature. All measured parameters are in good agreement with the results of numerical simulations conducted using the finite element method.