High-Spatial-Resolution Strain Sensor Based on Rayleigh-Scattering-Enhanced SMF Using Direct UV Exposure

A high-spatial-resolution, i.e., 2.0 mm, strain sensor based on a Rayleigh-scattering-enhanced SMF, i.e., exposed SMF (E-SMF) with direct UV laser, was experimentally demonstrated. The enhancement of Rayleigh-scattering (RS) intensity could be tuned by adjusting the exposure parameters, i.e., distance between SMF and Phase mask, energy of UV laser and velocity of the SMF. A 1.0 m long E-SMF with a RS enhancement of 37.3 dB was obtained, where the exposure time was only 100 s. Compared with the un-exposed SMF (UE-SMF), the strain profiles of the E-SMF could be clearly demodulated without fluctuation at a spatial resolution of 2.0 mm using traditional cross-correlation algorithm when the applied strain was from 200 to 2600 μϵ.