Refractive index and temperature optical fiber sensor based on thin core S-taper and spherical structure

Abstract

A Mach-Zehnder interferometer (MZI) for simultaneously measuring refractive index (RI) and temperature is proposed and verified in this paper. The sensor head is composed of thin core fiber (TCF) S-taper structure and spherical structure. By monitoring two interference dips, experimental results show that the RI sensitivities are −70.392 nm/RIU and −60.08 nm/RIU in the RI range of 1.338 4–1.350 0, respectively. And the temperature sensitivities are 0.050 72 nm/°C and 0.071 7 nm/°C in the temperature range of 30–70 °C, respectively. The simultaneous measurement of the temperature and external RI is demonstrated based on the sensitive matrix. The sensor also has the advantages of low cost, simple structure and high sensitivity.

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