S-Band long-distance fiber Bragg grating sensor system

We propose and investigate experimentally a sigma fiber laser scheme, which uses multiple fiber Bragg grating (FBG) sensors as the feedback elements, for a long-distance sensor system with 20-km long in S-band at first. By tuning a wavelength selective filter located in a laser cavity over the gain bandwidth, the laser selectively lases at each of the fiber Bragg wavelengths of the sensors, thus allowing strain-induced shifts in the Bragg wavelengths to be monitored. In our experiment, an S-band four-sensor system is proposed and investigated experimentally.