Optical Fiber Relative Humidity Sensor Based on a FBG with a Di-Ureasil Coating

• Autor(a) principal: Correia, Sandra F. H.
• Data de Publicação: 2012
• Outros Autores: Antunes, Paulo, Pecoraro, Édison [UNESP], Lima, Patricia P., Varum, Humberto, Carlos, Luis D., Ferreira, Rute A. S., Andre, Paulo S.
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Institucional da UNESP
• Texto Completo: http://dx.doi.org/10.3390/s120708847; http://hdl.handle.net/11449/26170
• topic: fiber Bragg gratings; optical fiber sensors; relative humidity; organo-silica hybrid; structure health monitoring

In this work we proposed a relative humidity (RH) sensor based on a Bragg grating written in an optical fiber, associated with a coating of organo-silica hybrid material prepared by the sol-gel method. The organo-silica-based coating has a strong adhesion to the optical fiber and its expansion is reversibly affected by the change in the RH values (15.0-95.0%) of the surrounding environment, allowing an increased sensitivity (22.2 pm/%RH) and durability due to the presence of a siliceous-based inorganic component. The developed sensor was tested in a real structure health monitoring essay, in which the RH inside two concrete blocks with different porosity values was measured over 1 year. The results demonstrated the potential of the proposed optical sensor in the monitoring of civil engineering structures.