Simultaneous measurement of refractive index and temperature of seawater based on surface plasmon resonance in a dual D-type photonic crystal fiber

Abstract

A dual D-type photonic crystal fiber (PCF) was proposed in this work to measure the refractive index and temperature of seawater. Two golden layers were designed to be coated on the two polished planes in the dual D-type PCF. Two confinement loss peaks in the transmission spectrum appeared due to the surface plasmon resonances which were inspired on the two golden layers. In order to achieve two-parameter sensing, one of the two polished planes was further coated with a polydimethylsiloxane (PDMS) layer which was temperature-sensitive. Seawater was assumed to be coated on the outer surface of the PCF. Numerical results by using the finite element method showed that the measurement sensitivity of the refractive index of seawater reached 1371 and 1228 nm/RIU, while the measurement sensitivity of temperature reached −0.3 and −1.06 nm/ °C, respectively. Finally, we obtained the transfer matrix expression which could be used to measure the refractive index and temperature of seawater simultaneously. The designed dual D-type PCF, which is simple in structure, highly sensitive and two-parameter measuring, could be a promising candidate for the monitoring of seawater.

D-Shaped Surface Plasmon Photonic Crystal Fiber Temperature Sensor

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A Reconfigurable Surface-Plasmon-Based Filter/Sensor Using D-Shaped Photonic Crystal Fiber

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Wedged Fiber Optic Surface Plasmon Resonance Sensor for High-Sensitivity Refractive Index and Temperature Measurements

“…One of the most common applications of the fiber optic SPR sensing system is temperature monitoring, which has been reported extensively in recent years [ 13 , 14 ]. For instance, SPR temperature sensors have been reported based on various fiber structures, including U-shaped fiber [ 15 , 16 ], D-shaped fiber [ 17 , 18 ], internally filled hollow fiber [ 14 , 19 ], spliced fiber [ 20 , 21 ], etc. The above sensors have been shown to have good sensing performance, but their detection method is transmission type, which limits the application of the sensing system.…”