Temperature Compensated Magnetic Field Sensor Using Magnetic Fluid Filled Exposed Core Microstructure Fiber

A temperature compensated magnetic field sensor using magnetic-fluid (MF) filled exposed core fiber (ECF) has been proposed to detect magnetic field strength and temperature (MFT) simultaneously in this paper. The designed sensor was formed by splicing an ECF between two sections of single-mode fibers (SMFs), in which the ECF’s exposed side was filled with MF. ECF is a multi-mode fiber that supports multiple modes of light-transmitting and produces mode interference in the core. Different order modes of light excited in the ECF have individual sensitivities to MFT. Therefore, interference spectra of two different pair modes can be monitored to measure MFT simultaneously. The results show that the sensor responds well to MFT. The maximum MFT sensitivities are -0.18 nm/mT and -0.16 nm/°C, respectively. The limit of detections (LODs) of MFT are 1.7 mT and 1.9°C, respectively. The sensor is particularly suitable for simultaneous detection of MFT in narrow spaces, such as industrial flaw detection, aerospace, and medical applications.