Distributed Fluorescence Oxygen Sensor

The evanescent field of light propagating in an optical fiber core extends into the cladding; this can cause the optical absorbance of the cladding to affect the transmission loss of the fiber itself. The fact that the evanescent fields of propagating modes in the fiber extend into the cladding also means that the inverse effect is possible: light generated in the cladding can be coupled to guided modes and transmitted over long distances. This work describes a fluorescence-based distributed oxygen sensor which makes use of this process.