Finite element analysis of an optical fibre electric field sensor using piezoelectric polymer coating

A novel approach for analysing an optical fibre electric field sensor by using the finite element method is presented. A singlemode optical fibre carrying a transversely poled piezoelectric poly(vinylidene fluoride) polymer coating was successfully modelled by using three-dimensional analysis. The response of the optical fibre electric field sensor was determined over a wide frequency range from 100 Hz to 50 MHz. The modelling predicts a phase shift of 0.019 rad V-1 m(-1) in the low frequency (axially unconstrained) region and 0.00082 rad V-1 m(-1) in the high frequency (axially constrained) region. At frequencies higher than 7 MHz the optical response is dominated by radial resonances of the fibre-jacket composite. Good agreement exists between the resonance peaks predicted by the simulation and those theoretically calculated using composite theory.