Fiber optic grating inscription over splice interface for strain and temperature measurement

A novel fiber Bragg grating(FBG) with three reflection wavelengths is proposed and demonstrated experimentally by simply phase-mask-based grating inscription over the splice interface between a thin-core fiber (TCF) and a standard single-mode fiber (SMF). The key to the success of this device lies in the refractive index differences between SMF, TCF and splice interface, and the precisely localized grating inscription over the three regions. The reflection wavelengths present different sensitivities to temperature and strain, making it as a good candidate for the measurements of two parameters simultaneously.