Response of fibre optic long period gratings operating near the phase matchingturning point to the deposition of nanostructured coatings.

摘要

The response of the dual resonant bands of a fibre optic long period gratingoperating near the phase matching turning point to the deposition of ananostructured coating is investigated. The dual resonant bands are observed toshow a high sensitivity to the thickness of the coating, but with oppositesigns. Appropriate design of the device, based on the grating period, therefractive index and thickness of the coating and the fibre composition, canallow the sensitivity of the device to the optical thickness to be optimized. Asensitivity of 1.45 nm / nm is observed experimentally.