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Metallic coating techniques for fiber Bragg grating sensors

Fiber Bragg Grating sensors (FBG) have a great resistance to embedding processes. This property is very useful for monitoring parameters at inaccessible places. Embedded fiber optic sensors into composites have been studied for a long time, but embedding a fiber sensor into metallic structure is beginning to study. Recently, this has raised interest due to embedded FBG in the metallic structure provide capabilities for controlling parameters of the structural health status and also information about their own process of deterioration. The embedding process of the FBG sensors involves the fusion of structural metallic material. During this process, very high temperatures are achieved that could damage the Bragg grating or the silica fiber. To protect the sensor during the embedding process, a fiber coating is made with a metallic material with a high melting point. In this paper we study three different techniques for coating a FBG sensor: physical vapour deposition (PVD), electroless deposition and electroplating. This paper describes the experimental procedure for coating metallic fiber optic sensors and the optical characterization.