Enhancement of sensitivity in long period fiber gratings with deposition of low refractive index materials

It was proved [Opt. Lett. 30, 720 (2005)] that the deposition of an overlay of higher refractive index than that of the cladding on a long-period fiber grating (LPFG) causes large shifts in the attenuation bands induced by the grating. The result is an enhancement of the sensitivity of the LPFG to v...

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Detalles Bibliográficos
Autores: Del Villar, Ignacio, Matías Maestro, Ignacio, Arregui San Martín, Francisco Javier
Tipo de recurso: artículo
Estado:Versión aceptada para publicación
Fecha de publicación:2005
País:España
Institución:Universidad Pública de Navarra
Repositorio:Academica-e. Repositorio Institucional de la Universidad Pública de Navarra
OAI Identifier:oai:academica-e.unavarra.es:2454/28198
Acceso en línea:https://hdl.handle.net/2454/28198
Access Level:acceso abierto
Palabra clave:Long period fiber Bragg gratings
Optical fiber sensors
Thin-films
Coupled-mode theory
Descripción
Sumario:It was proved [Opt. Lett. 30, 720 (2005)] that the deposition of an overlay of higher refractive index than that of the cladding on a long-period fiber grating (LPFG) causes large shifts in the attenuation bands induced by the grating. The result is an enhancement of the sensitivity of the LPFG to variations in the ambient and overlay refractive indices or the overlay thickness. The limitation of the previous design to materials with higher refractive indices than that of the cladding of the LPFG is overcome with a five-layer model. To this purpose, a first overlay of higher refractive index than that of the cladding of the LPFG will enhance the sensitivity of the device to variations in the refractive index of a second overlay of lower refractive index than that of the cladding of the LPFG. Moreover, it is proved that, if the second overlay is thick enough, its behavior resembles that of an infinite layer