Multiplexed Optical Fiber Biochemical Sensing Using Cascaded C-Shaped Fabry–Perot Interferometers

Abstract

A multiplexed fiber sensor is proposed based on Fabry-Perot interferometers formed by serially splicing C-shaped and single mode fibers. We first demonstrate multiplexed refractive index sensing by independently filling and measuring sodium chloride (NaCl) solutions with different concentrations in a two-cavity system. The results show minimal cross-talk between the two interferometers. The dual-cavity interferometric sensor was then applied to biochemical sensing by utilizing polyelectrolyte layer by layer self-assembly followed by the biotin-streptavidin binding mechanism. The proposed sensor solves an important problem in biochemical sensing by providing an ability to simultaneously measure a negative control, critical for reducing false positive measurements.