Wide-Range Dynamic Strain Sensing Based on Dual-Frequency Fixed Slope-Assisted Chaos BOCDA

This paper proposes a dual-frequency fixed slope assisted scheme for wide-range and high-precision dynamic strain sensing within a chaotic Brillouin optical correlation domain analysis. The method addresses key limitations in conventional slope-assisted techniques, such as the requirement for multiple pre-analysis Brillouin gain spectra (BGS) and the presence of demodulation empty areas. By utilizing two fixed frequencies on a single slope, the scheme halves the number of required BGS and effectively eliminates errors caused by empty regions. Compared to conventional schemes requiring eight BGS for 8,000 μϵ, it achieves nearly 50 μϵ accuracy using only four gain spectra in the sequential arrangement and two gain spectra in the cross arrangement, reducing errors by approximately 50%.