Brillouin optical correlation domain analysis based on a phase-chaos laser

The physical mechanism of gain motivation is the main theoretical bottleneck that restricts the signal-to-noise ratio (SNR) and results in a mono-merit implementation for the existing stimulated Brillouin scattering-based fiber sensors. A phase-chaos laser (PCL) is proposed and introduced in the Brillouin optical correlation domain analysis (BOCDA) scheme to promote the SNR and achieve a high-accuracy measurement. The PCL characteristics are presented, and a theoretical model of chaos gain accumulation and extraction is perfected. Then, the simulation results reveal that the SNR is improved by 5.56 dB, and the signal-to-background noise ratio (SBR) of the Brillouin gain spectrum (BGS) is promoted by 8.28 dB with a 100-km sensing distance. Further, the PCL is experimentally generated. In the proof-of-concept experiment, the accuracy of the Brillouin frequency shift is upgraded to ±0.64 MHz, and the SBR of BGS is improved by 10.77 dB. The PCL provides a new research direction for optical chaos, and the PCL-BOCDA showcases a promising future for optimal-merit-coupling sensing and its application.