Microstructured Fibers Optimized for Transverse Load and Pressure Sensing

We first shortly review the state-of-the-art of microstructured optical fiber Bragg grating (MOFBG) sensors for transverse load and pressure monitoring applications. We then focus on a specific microstructured fiber design to which we refer as ‘Butterfly’ MOF. This fiber is highly birefringent and has a large mechanical asymmetry. Its microstructure was optimized to encode loads perpendicular to the fiber's axis into a change of the spectral distance between the two Bragg peaks reflected by a fiber Bragg grating in this fiber. Such MOFBG sensors allow measuring transverse strains and hydrostatic pressures with an order of magnitude increase of the sensitivity over conventional birefringent fibers. We then discuss the potential of our MOFBG sensors for structural health monitoring related applications, including high-pressure sensing, three-dimensional strain measurements inside composite materials and disbond monitoring in adhesive joints based on shear strain measurements.