Recent Advances of Brillouin Optical Correlation-Domain Analysis for Enhanced Sensing Accuracy

Optical fiber sensors based on Brillouin scattering were first introduced over three decades ago, and various types of distributed sensing schemes have been developed. The Brillouin optical correlation domain analysis (BOCDA), first proposed in 2000, is a quasi-distributed Brillouin sensor which supports arbitrary access to a sensing position by the frequency modulation of a continuous-wave light source. Compared to time-domain distributed sensors, the BOCDA is more suitable for the measurement requiring a high spatial resolution or high sampling rate in a relatively short sensing distance. In this paper, we present technical reviews on recent technologies that can be applied to improve the sensing accuracy of a BOCDA system, such as differential measurement, injection-locking, and orthogonally polarized probe sidebands.