Linearly Configured Brillouin Optical Correlation Domain Analysis System Incorporating Time-Domain Data Processing

We propose a linearly configured Brillouin optical correlation domain analysis system incorporated with time domain data processing, where a fiber under test (FUT) is accessed from single end and multiple sensing points are simultaneously interrogated to extend the measurement range. In our scheme, correlation peaks (CPs) are sequentially generated by the interaction between a pump pulse outgoing from the system and a probe wave reflected from the end of an FUT, where the time-domain data processing is applied to obtain the Brillouin gain spectrum of each CP. In experiments, we demonstrate simultaneous acquisition of Brillouin gain spectra at 982 CPs with a spatial resolution of less than 5 cm and a sensing range extended from 10.3 m to 10.15 km. We also show that the amplitude of frequency modulation (Δf), which has been limited to the Brillouin frequency of an FUT in linear-configured BOCDA systems, can be enlarged without definite limitation by the time-domain data processing. In the experimental confirmation Δf of 15.6 GHz, about 1.5 times of the Brillouin frequency of FUT, is successfully applied to simultaneous analysis of 98 CPs by the time-domain data processing.