Hydrostatic pressure and temperature cross-sensitivity in Rayleigh scattering-based distributed fiber measurements

In this paper, the cross-sensitivity of distributed measurements based on Rayleigh scattering to hydrostatic pressure and temperature in a birefringent K-type side-hole optical fiber is investigated. The aim is to determine the potential for simultaneous, real-time monitoring of changes in these parameters over a large distance or area, with high spatial resolution (around 1mm). The fiber responses to hydrostatic pressure changes measured at room temperature for orthogonal polarization modes are linear, have opposite signs, and are approximately -1.9 GHz/MPa and 0.8 GHz/MPa. The tested fiber, measured at atmospheric pressure, shows a nonlinear, almost identical response to temperature for both orthogonal polarization modes, approximately -1.5 GHz/°C. Additionally, the fiber responses to pressure changes were measured at different temperatures.