Magnetic field and temperature two-parameter sensor based on optical microfiber coupler interference (OMCI) wrapped with magnetic fluid and PDMS

In this paper, an optical fiber magnetic field and temperature sensor based on an optical microfiber coupler (OMC), Polydimethylsiloxane (PDMS), and magnetic fluid (MF) is proposed, and its magnetic field and temperature sensing characteristics are analyzed theoretically and verified experimentally. Based on the OMC and using MF as the sensing medium, the sensor can respond to the magnetic field and temperature respectively after encapsulated by PDMS. The experimental results show that the maximum magnetic field sensitivity is 96.8 pm/Oe, and the maximum temperature sensitivity is 919.1 pm/°C. To overcome the cross-sensitivity of the magnetic field and temperature of the sensor, the sensitivity matrix is established and demodulated. In addition, we discuss the optimization of the sensitivity demodulation matrix by the size design of the PDMS package and the OMC structure. The proposed two-parameter sensor in this article has the advantages of high sensitivity, low cost, small volume and high integration, which is of great significance for the multi-parameter sensing of basic physical parameters such as magnetic field and temperature.