Title :
Nanodeposition of materials with complex refractive index in long-period fiber gratings
Author :
Del Villar, Ignacio ; Matias, Ignacio R. ; Arregui, Francisco J. ; Achaerandio, Miguel
Author_Institution :
Electr. & Electron. Eng. Dept., Public Univ. of Navarra, Pamplona, Spain
Abstract :
An overlay of higher refractive index than the cladding is deposited on a long-period fiber grating (LPFG). This causes large attenuation-band shifts in the transmission spectrum, which permits the improvement of the sensitivity of the device to ambient and overlay refractive-index changes. To obtain maximum sensitivity for specific overlay and ambient refractive indexes, an optimum overlay thickness (OOT) must be selected. For complex overlay refractive indexes, there is an additional phenomenon of vanishing of the attenuation bands. This occurs for specific overlay-thickness values. The problem is analyzed with a numerical method based on linearly polarized (LP)-mode approximation and coupled-mode theory. Experimental results are contrasted with theoretical ones.
Keywords :
coupled mode analysis; diffraction gratings; fibre optic sensors; nanotechnology; optical fibre cladding; optical fibre polarisation; refractive index; ambient refractive index; complex refractive index; coupled-mode theory; device sensitivity; fiber cladding; large attenuation-band shifts; linearly-polarized mode approximation; long-period fiber gratings; material nanodeposition; optimum overlay thickness; transmission spectrum; Bragg gratings; Couplings; Fiber gratings; Nanostructured materials; Optical fiber communication; Optical fiber devices; Optical fiber polarization; Optical fiber sensors; Refractive index; Temperature sensors; Coupled-mode analysis; long-period gratings; nanodeposition; optical fiber sensors; refractive index;
Journal_Title :
Lightwave Technology, Journal of
DOI :
10.1109/JLT.2005.858246
