Fabrication and sensing characterization of an S-tapered fiber probe

Abstract

This paper presents and analyzes S-tapered fiber probe structures. Cutting a conventional S-tapered fiber and coating its ends with gold film forms a highly reliable reflective layer. We acquire the reflection spectrum and use it to determine the refractive index (RI) sensitivity of this structure for various RIs and temperatures. The experimental results suggest that this S-tapered fiber probe structure has a maximum RI sensitivity of 1441 nm/RI unit in the RI range of 1.336-1.340 and a temperature sensitivity of about 0.7537 nm/°C. In addition, we analyze in detail the mechanism responsible for these high sensitivities.