Response of FBGs in Microstructured and Bow Tie Fibers Embedded in Laminated Composite

Fiber Bragg gratings in bow tie fiber and highly birefringent microstructured optical fiber are embedded in a carbon fiber reinforced epoxy. The Bragg peak wavelength shifts of the embedded gratings are measured under controlled bending, transversal loading, and thermal cycling of the composite sample. We obtain similar axial and transversal strain sensitivities for the two embedded fiber types. We also highlight the low temperature dependence of the Bragg peak separation of the microstructured fibers, which is an important advantage for this application. The results show the feasibility of using microstructured fibers in structural integrity monitoring.