Double-side polished U-shape plastic optical fiber based SPR sensor for the simultaneous measurement of refractive index and temperature

A double-side polished U-shape plastic optical fiber (POF) based SPR sensor is proposed for measuring the refractive index (RI) and temperature simultaneously. The polished regions are fabricated on two sides of the macrobending regions, and a layer of gold film is deposited on both polished regions. The influences of the side-polish depth and angle on the sensing performance are investigated. The two-parameters sensor can be obtained by coating a layer of polydimethylsiloxane (PDMS) film on one of the gold-film surfaces, and the RI and temperature can be detected by monitoring the resonance peak wavelength changes. A RI sensitivity of 1258 nm/RIU and a temperature sensitivity of –0.596 nm/∘C are achieved in the experiment. The proposed probe has potential applications in the field of environmental monitoring.