Two-Channel Surface Plasmon Resonance Sensor for Simultaneous Measurement of Seawater Salinity and Temperature

A new type of two-channel surface plasmon resonance (SPR) sensor based on hollow-core fiber (HCF) for simultaneous measurement of seawater salinity and temperature was presented in this article. One of the SPR channels that are excited on the outer surface of the HCF with Au film coating was used to measure the seawater salinity, while another SPR channel that is excited on the inner surface of the HCF with Ag film coating and polydimethylsiloxane (PDMS) infiltration was used for seawater temperature measurement at the same time. The experimental results showed that the salinity sensitivity and temperature sensitivity of the sensor could reach 0.3769 nm/ ⁰ / ₀₀ and -0.956 nm/°C, respectively. This demonstrated that the two-channel SPR sensor not only showed the possibility in the simultaneous measurement of two parameters with high sensitivity, excellent stability, small size, and high mechanical strength but also shed new light on the multiparameter measurement fields and the development of lab-in-fiber sensors.