Simultaneous measurement of magnetic field and temperature based on photonic crystal fiber plasmonic sensor with dual-polarized modes

A photonic crystal fiber (PCF) based on surface plasmon resonance (SPR) sensor with two orthogonally polarized core modes is designed to achieve simultaneous measurement of magnetic field and temperature. According to the sensing principle, four large ring microfluidic detection channels coated with silver-tantalum pentoxide (Ag-Ta2O5) composite films are symmetrically distributed in the PCF cladding, where the upper and lower channels are filled with magnetic fluids (MFs), and the temperature-sensitive material is infiltrated into the left and right channels. The refractive index (RI) of the MFs has strong dependence on the magnetic field and temperature, while the RI of the temperature-sensitive material is merely affected by the temperature. Therefore, the information on the magnetic field and temperature carried by two orthogonally polarized core modes can be separated. The effect of the structure parameters of the proposed sensor on the sensing performance are evaluated through the optical loss spectrum based on finite element method (FEM). The numerical results show that a dual-parameter sensing matrix on simultaneous measurement of the magnetic field and temperature is established, revealing a magnetic field sensitivity of 265 pm/Oe in the range of 20–300 Oe and a temperature sensitivity of − 1410.7 pm/°C in the range 20–80 °C. The designed sensor overcomes the cross-sensitivity problem when the magnetic field and temperature are measured at the same time, which has a potential application in the fields of dual-parameter sensing.