Simultaneous measurement of strain, temperature and curvature using a sampled fibre Bragg grating

We have shown that a single superstructured fibre Bragg grating (SFBG) can be used to provide simultaneous measurements of strain, temperature, and curvature. The spectral splitting of the SFBG loss bands facilitates measurement of the curvature, whilst the wavelength shift of the FBG harmonics and that of the midpoint between the split bands provides for determination of the axial strain. and temperature.