Multiplexed static FBG strain sensors by dual-comb spectroscopy with a free running fiber laser.

We demonstrate a novel and compact FBG interrogation system for multiplexed static strain sensing with a free running mode-locked fiber laser. Multiplexed FBG array in cascading are interrogated by coherent dual-comb pulses generated from a single fiber laser. Dual-comb spectroscopy is achieved with the fiber laser to precisely detect the strain-induced spectral shifts of the FBG sensors. Multi-point strain measurements are performed to characterize the proposed system, where a large dynamic range of 520 με with 0.5 με resolution is achieved.