Measurement Range Elongation Based on Temporal Gating in Brillouin Optical Correlation Domain Distributed Simultaneous Sensing of Strain and Temperature

We had earlier demonstrated the distributed discrimination of strain and temperature by localizing and scanning both the stimulated Brillouin scattering and the Brillouin dynamic grating along a polarization-maintaining fiber. The localization and scanning were performed by a correlation domain technique, whose measurement range was restricted by the distance between consecutive correlation peaks. To overcome this restriction, in this letter, we apply a temporal gating scheme to the system by enlarging the measurement range from ~25 to ~500 m. We report the results confirming the effectiveness of this scheme in a system operated by a single laser source, and demonstrate the strain-temperature discrimination when strain or temperature is applied to segments on the 500-m-long fiber under test.