Tapered polymer optical fiber oxygen sensor based on fluorescence-quenching of an embedded fluorophore

We have developed a new method of processing fiber optic oxygen gas sensors based on fluorescent quenching by directly and locally incorporating the fluorophore into the optical fiber that is going to serve as waveguide. This procedure circumvents the preparation steps of the sensing polymer matrix and the later coating of the optical fiber. The sensor combines a side illumination technique with the localized tapering of the fiber, where the fluorophore is placed, to increase the signal to noise ratio. We have fully characterized it and our sensor performance is comparable in sensitivity and response time to those based on polymer matrix fluorophore embedding. We also have studied the addition of a second fluorophore unresponsive to oxygen to serve as a reference for the stability of the excitation source.