Extending the measurement range of Brillouin optical correlation domain analysis through asymmetric adjustment of Stokes and anti-Stokes intensities

We present a significant advancement in Time-Domain Brillouin Optical Correlation Domain Analysis (TD-BOCDA) technology by exploiting the intensity imbalance between Stokes and anti-Stokes components in the Brillouin probe wave. Through a systematic comparison of Brillouin frequency distributions under various sideband modulation conditions, we have successfully extended the measurement range of the TD-BOCDA system. Notably, we achieved a 50 km measurement range with a high spatial resolution of 7 cm without the need for optical amplification. This remarkable performance was attained by optimizing the intensity difference between Stokes and anti-Stokes components to 7 dB.