Refractive index tip sensor based on Fabry-Perot cavities formed by a suspended core fibre

A Fabry-Perot refractometer based on the suspended core fibre is presented. The Fabry-Perot cavities are formed by a section of suspended core fibre between conventional single-mode fibres. This miniature refractive tip sensor is demonstrated for the measurement of the refractive index change by measuring the fringe visibility and through the analysis of the fast Fourier transform. The two methods are compared. The temperature dependence was also characterized. [DOI: 10.2971/jeos.2009.09041]