Fiber Bragg grating optochemical sensor basing on evanescent-field interaction with surface plasmon waves

Fiber Bragg grating sensors in side-polished optical fiber are sensitive to an external analyte by evanescent field interaction. Deposition of sensor-specific transducer layers can advance such fiber Bragg grating refractometer to the optochemical monitoring of specific substances: absorbed gases, vapors, and adsorbed biomolecules as well. Refractive index range of highest sensitivity can be adjusted to the analyte medium of interest by proper construction of the multilayer waveguide. A specific application example aims at hydrogen detection using a palladium thin film transducer.