Microstructured Optical Fiber Bragg Grating Sensors for Structural Health Monitoring Applications

We first shortly review the state-of-the-art of microstructured optical fiber Bragg grating (MOFBG) sensors for structural health monitoring applications. We then focus on a specific microstructured optical fiber (MOF) design to which we refer as OButterflyO MOF. This fiber is highly birefringent and encodes the transverse strain into the spectral distance between the two Bragg peaks reflected by a fiber Bragg grating fabricated in this fiber. Since the birefringence of that MOF is not sensitive to temperature changes, the transverse strain measurement is independent of temperature variations. We subsequently discuss the potential of our MOFBG sensors for structural health monitoring related applications, including three-dimensional strain measurements within composite materials, cure monitoring and residual strain quantification following composite material manufacturing, shear stress measurements in lap joints and temperature insensitive vibration monitoring.