Sensitivity Characteristics Tuning in Tapered Long Period Gratings by Nanocoatings

The experimental analysis of the response of nanocoated tapered long-period gratings to surrounding refractive index (SRI) changes is presented. The modal transition is demonstrated to be an effective method to improve their SRI sensitivity over a broad SRI range. The dip-coating method is shown to be a reliable technique for the deposition of conformal coatings with the necessary thickness control to tune the transition region in the desired SRI range.