Photonic Crystal Fiber-Based Interferometric Biosensor for Streptavidin and Biotin Detection

• Published in: IEEE journal of selected topics in quantum electronics 2012-07, Vol.18 (4), p.1293-1297
• Main Authors: Hu, Dora Juan Juan, Lim, Jun Long, Park, Mi Kyoung, Kao, Linus Tzu-Hsiang, Wang, Yixin, Wei, Huifeng, Tong, Weijun
• Format: Article
• Language: English
• Subjects: Biomedical measurements; biophotonics; Biosensors; Optical fiber cables; optical fiber devices; Optical fiber sensors; Optical fibers; Photonic crystal fibers; photonic crystal fibers (PCF); refractive index (RI)
• ISSN: 1077-260X; 1558-4542
• DOI: 10.1109/JSTQE.2011.2169492

We report the fabrication of a highly sensitive refractometer based on photonic crystal fiber (PCF) interferometry. Using fusion arc splicing technique, a short length of PCF (∼3 mm) was spliced to conventional single-mode fibers on both sides. The voids of the PCF were completely collapsed in the splice region, which acted as mode splitter and combiner on both sides. Microbubbles were formed in the splice region and acted as diverging lens for exciting cladding modes efficiently. The transmission spectrum exhibited detectable "dips" for refractive index (RI) sensing. The bulk liquid sensitivity can reach up to 320 nm/RIU (RI unit) based on the linear curve fit for RI ranging from 1.33 to 1.34. Biosensing experiment was carried out using streptavidin and biotin as respective analyte and receptor. To the best of authors' knowledge, this is the first time of reporting bioaffinity test on the external surface of PCF using modal interferometry.