Del Villar, Ignacio2018-03-272018-03-2720151094-4087 (Electronic)10.1364/OE.23.008389https://academica-e.unavarra.es/handle/2454/28106The 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 × 103 nm/RIU is obtained, the highest reported so far with long period fiber gratings.application/pdfeng© 2015 Optical Society of America. Users may use, reuse, and build upon the article, or use the article for text or data mining, so long as such uses are for non-commercial purposes and appropriate attribution is maintained. All other rights are reserved.Fiber optics sensorsFiber Bragg gratingsThin filmsinfo:eu-repo/semantics/articleinfo:eu-repo/semantics/openAccess