Experimental fiber optic humidity sensor with applicability to civil structures health monitoring

This paper presents the results obtained in the execution of the first steps of the functional evaluation process of a fiber optic relative humidity sensor.The sensor device was a long period fiber grating (LPG) whose manufacturing process is described.Information is provided on how a humidity sensitivity level was reached that allows relative humidity (RH) measurements to be made.Packaging design implemented is described.Experimental arrangements used for thermal characterization and for humidity response are described.The results are discussed highlighting the details of the experimental setup to be improved in the future.Finally, the conclusions that qualify the feasibility of the implementation of an embedded humidity sensor in concrete structures by using this type of technology are provided.