Temperature-Insensitive Magnetic Field Sensor Based on Nanoparticle Magnetic Fluid and Photonic Crystal Fiber

A novel magnetic field sensor based on the magnetic fluid and Mach-Zehnder interferometer is proposed. The sensor takes advantage of the tunable refractive index property of the magnetic fluid and the modal interference property of the collapsed photonic crystal fiber. The achieved sensitivity and resolution of the sensor are 2.367 pm/Oe and 4.22 Oe, respectively. The magnetic field sensor is insensitive to the temperature variation with a temperature coefficient of 3.2 pm/°C.