Polarization-sensitive optical fiber-tip ball resonators for refractive index sensing with optical backscatter reflectometer interrogator

• Published in: Optical fiber technology 2021-07, Vol.64, p.102551, Article 102551
• Main Authors: Shaimerdenova, Madina, Ayupova, Takhmina, Nugmanova, Aigerim, Dauletova, Ayazhan, Tosi, Daniele
• Format: Article
• Language: English
• Subjects: Ball resonator; Microsphere; Optical backscatter reflectometry; Optical fiber sensors; Polarization sensors; Refractive index sensors
• ISSN: 1068-5200; 1095-9912
• DOI: 10.1016/j.yofte.2021.102551

•We present optical fiber ball resonators interrogated via optical backscatter reflectometry.•Ball resonators have polarization-sensitive spectral signature.•We present the result of 4 samples, having sensitivity ranging from 366.6 dB/RIU to 6691.6 dB/RIU.•Without any additional component, the sensitivity increase is 18.6%–47.7% over standard interrogation. Optical fiber-tip ball resonators are inexpensive devices characterized by a rapid, repeatable, and reliable fabrication process through a fiber splicer. The spectral features of a ball resonator appear as low-finesse interferometer, with an optical backscatter reflectometer (OBR) interrogator. The spectrum changes in amplitude when the external refractive index (RI) varies. In this work, we present a polarization-sensitive method for the detection of spectral changes in ball resonators. We achieved a sensitivity ranging from 366.6 dB/RIU to 6691.6 dB/RIU (refractive index units) on the most sensitive polarization, improving the sensitivity of a standard detection of 18.6%–47.7% without the need of any additional component.