Improvement of Strain Measurement Accuracy and Resolution by Dual-Slope-Assisted Chaotic Brillouin Optical Correlation Domain Analysis

Abstract

A dual-slope-assisted chaotic Brillouin optical correlation domain analysis (DSA-CBOCDA) technique is proposed to improve the measurement accuracy and resolution for static and dynamic strain sensing. By using the gain ratio obtained from two slopes of the Brillouin gain spectrum (BGS), the influence of random fluctuation in chaotic pump power on the measurement result is alleviated. Compared with the previous single-slope-assisted CBOCDA, the measurement accuracy of the DSA-CBOCDA is improved from 25.0 μϵ to 3.9 μϵ for the static strain, and from 28.5 μϵ to 6.2 μϵ for the dynamic strain. Meanwhile, the static strain resolution of 10 μϵ and dynamic strain resolution of 15 μϵ are verified in the experiment. Moreover, the dynamic strain measurement range of 800 μϵ for the proposed DSA-CBOCDA system is also experimentally confirmed, which is approximately fivefold larger than the current DSA-based Brillouin sensing system.