Salinity sensor using photonic crystal fiber

A salinity sensor employing photonic crystal fiber is designed for measuring the concentration of salt in sea water. The sea water sample is infiltrated into one of the air holes in cladding, which offers high confinement loss and act as an analyte core mode and background acts as silica mode. In order to satisfy the phase matching condition, the power transferred from silica core to the liquid filled analyte core, which is investigated using finite element method. An enhanced sensitivity of salinity in sea water reports as 5405 nm/RIU for x-polarization and 5675 nm/RIU for y-polarization with a detection limit of 0.0037 RIU has been reported. The proposed PCF also promises to yield the large birefringence of order 10−3 along with the enhanced sensitivity.