Magnetic Field and Temperature Two-Parameter Sensor Based on Mach–Zehnder Interferometer and Faraday Rotation Effect

A novel combination of structural design and sensing theory is proposed for an optical fiber magnetic field and temperature two-parameter sensor based on the Mach–Zehnder interferometer (MZI) and Faraday rotation effect. The sensor structure includes a polydimethylsiloxane (PDMS) microcavity and a small Section of offset spliced fiber. Numerical analysis shows that the sensor exhibits high-temperature sensitivity, which has been experimentally verified. The sensor has a temperature sensitivity of −846 pm/°C in the 20 °C to 35 °C and a magnetic field intensity sensitivity of 190 pm/Gs in the range of 0–150 Gs. The temperature and magnetic field intensity responses of the sensor are linear and have been optimized for sensitivity demodulation. The sensor is well-suited for standardized monitoring of temperature and magnetic field in applications requiring accurate measurements.