Triple-Channel Optical Fiber Surface Plasmon Resonance Sensor for Simultaneous Detection of Relative Humidity, Magnetic Field, and Temperature

In this work, we propose a transmission-type in-line three-channel sensor for relative humidity, magnetic field, and temperature monitoring, which consists of three consecutively cascaded gold-plated side-polished optical fibers. The surface plasmon resonance (SPR) effect is adopted. The three sensor probes are coated with humidity-sensitive polyvinyl alcohol (PVA), magnetic-field-sensitive magnetic fluid (MF), and temperature-sensitive polydimethylsiloxane (PDMS), respectively. The cross-sensitivity problem of multiparameter sensors is solved tactfully. Importantly, the proposed sensor has the characteristics of low crosstalk, simultaneous measurement, and high sensitivity, which is very useful for the simultaneous detection of multiple parameters. The obtained relative humidity sensitivity is 0.163 nm/%, magnetic field intensity sensitivity is 1.767 nm/mT, and temperature sensitivity is -2.680 nm/°C.