In order to embed the fiber Bragg grating (FBG) into intelligent metal structures, a
metallization of FBG is demanded. Ni-P alloy is usually deposited as a metal coating
on FBG by coarsening fiber, which will give some bad influence on the property of
fiber. So in this paper, a layer of Ni-P alloy was electroless plated on FBG without
coarsening of FBG, and the surface morphologies, composition, structure and
adhesion force of the coating film was characterized by SEM, XPS and XRD,
respectively. The results indicate that the alloy clad was very smooth, flat and
compact, and in amorphous state with a composition of Ni 71.73 at% and P 28.27 at%.
Moreover, the temperature sensing behavior of FBG metallized with and without
coarsening was compared, and a theoretical model of temperature sensitivity for Ni-P
coated FBG was presented. It shows that the temperature sensitivity of FBG without
coarsening increases was 0.01126 nm/°C, but 0.01098 nm/°C for the coarsened one.
Clearly, metalized FBG with no coarsening showed better sensing properties.