Detection of molecular oxygen by magnetic field interaction with guided light within an optical fiber

Abstract

We report a novel fiber-optic sensing architecture for the detection of paramagnetic gases that exploits the interaction of a magnetic field with guided light to detect an active gaseous medium within a hollow-core photonic bandgap fiber. This first demonstration of a fiber-based Faraday Rotation Spectroscopy (FRS) sensor operates at 762.309 nm for the detection of molecular oxygen. The optical fiber sensor has a 14.8 cm long sensing region and 4.2 nL detection volume. A measured FRS spectrum with a signal-to-noise ratio of 9.5 proves the principle of this new gas sensor architecture.