title: Ultrahigh-sensitivity sensors based on thin-film coated long period gratings with reduced diameter, in transition mode and near the dispersion turning point.
abstract: The mode transition and the dispersion turning point have been explored for optimization of thin-film coated long period fiber gratings during the last years. In this work and additional parameter, the cladding diameter, is combined with the other two phenomena for improving the sensitivity to the surrounding medium refractive index. The numerical data obtained were calculated with a method based on the exact calculation of core and cladding modes and the utilization of coupled mode theory. A sensitivity 143 × 10(3) nm/RIU is obtained, the highest reported so far with long period fiber gratings.
authors.forename: Ignacio
authors.initials: I
authors.lastname: Del Villar