Ultra-highly sensitive surface-corrugated microfiber Bragg grating force sensor

We experimentally demonstrate a microfiber Bragg grating force sensor with ultra-high sensitivity. The fiber Bragg grating (FBG) is inscribed in a microfiber tapered from standard non-photosensitive single-mode fiber by focused ion beam machining method, and has a compact size (similar to 112 mu m in length). Small diameter increases the force sensitivity of such grating when acting as a force-sensing element under tensile loads. We have demonstrated force sensitivity as high as similar to 3146 nm/N around the resonant wavelength of 1538 nm, which is three orders of magnitude larger than FBGs in untapered fibers. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4754838]