Long Period Grating-Based Fiber Coupling to WGM Microresonators

Francesco Chiavaioli, Dario Laneve, Daniele Farnesi, Mario Falconi, Gualtiero Nunzi Conti, Francesco Baldini, Francesco Prudenzano
2018 Micromachines  
A comprehensive model for designing robust all-in-fiber microresonator-based optical sensing setups is illustrated. The investigated all-in-fiber setups allow light to selectively excite high-Q whispering gallery modes (WGMs) into optical microresonators, thanks to a pair of identical long period gratings (LPGs) written in the same optical fiber. Microspheres and microbubbles are used as microresonators and evanescently side-coupled to a thick fiber taper, with a waist diameter of about 18 µm,
more » ... n between the two LPGs. The model is validated by comparing the simulated results with the experimental data. A good agreement between the simulated and experimental results is obtained. The model is general and by exploiting the refractive index and/or absorption characteristics at suitable wavelengths, the sensing of several substances or pollutants can be predicted.
doi:10.3390/mi9070366 pmid:30424299 pmcid:PMC6082267 fatcat:hd3si5czejfitenw74izn6bqfq