High-sensitivity strain sensor based on in-fiber improved Fabry-Perot interferometer

We demonstrated a high-sensitivity strain sensor based on an in-fiber Fabry- Perot interferometer (FPI) with an air cavity, which was created by splicing together two sections of standard single-mode fibers. The sensitivity of this strain sensor was enhanced to 6.0 pm/mu epsilon by improving the cavity length of the FPI by means of repeating arc discharges for reshaping the air cavity. Moreover, such a strain sensor has a very low temperature sensitivity of 1.1 pm/degrees C, which reduces the cross sensitivity between tensile strain and temperature. (C) 2014 Optical Society of America