Cascaded long-period gratings with nanostructured coatings

The response of the transmission spectrum of cascaded long period gratings (LPGs) to the deposition of nanostructured coatings by use of the Langmuir-Blodgett technique is investigated. The phase of the interference fringes within the LPGs' attenuation bands is shown to be highly sensitive to the optical thickness of the coating, for thicknesses of the order of 100 nm.