Half-side PDMS-coated dual-parameter PCF sensor for simultaneous measurement of seawater salinity and temperature

• Published in: Optical fiber technology 2021-09, Vol.65, p.102608, Article 102608
• Main Authors: Wang, Haoran, Dai, Weiyu, Cai, Xun, Xiang, Zhuowei, Fu, Hongyan, IEEE, Member
• Format: Article
• Language: English
• Subjects: Photonic crystal fiber; Salinity measurement; Seawater sensor; Surface plasmon resonance; Temperature measurement
• ISSN: 1068-5200; 1095-9912
• DOI: 10.1016/j.yofte.2021.102608

•A dual channel photonic crystal fiber is proposed for dual-parameter sensing.•The gold is coated on the outer surface of the sensor to measure the salinity.•The polydimethylsiloxane is coated on the half-side of the surface of the sensor.•The temperature sensitivity is −4.937 nm/°C in the sensing range from 25 °C to 50 °C.•The salinity sensitivity is 0.307 nm/‰ in the sensing range from 0‰ to 100‰. A novel half-side PDMS-coated photonic crystal fiber (PCF) sensor based on surface plasmon resonance (SPR) is proposed for simultaneous detection of seawater salinity and temperature. The plasmonic material gold is coated on the outer surface of the PCF to measure the seawater salinity by exciting SPR effect. Moreover, the polydimethylsiloxane (PDMS) layer is coated on the upper half-side of the surface of the sensor as an independent temperature sensing channel. The properties of modes coupling between surface plasmon polaritons (SPPs) mode and four different core modes are investigated. Meanwhile, the influence of various geometrical parameters on the sensing characteristics are theoretically simulated by using finite element method (FEM). The numerical results show that the salinity sensitivity of the designed sensor can reach 0.307 nm/‰ with a resolution of 0.3257‰. Additionally, the temperature sensitivity of −4.937 nm/°C with the resolution of 0.0203 °C in the sensing range from 25 °C to 50 °C has been obtained. The proposed sensor, possessing advantages such as ease of fabrication, excellent sensing performance and low cost, not only realizes the simultaneous measurement of two parameters, but also has potential in the field of seawater monitoring.