Long-range chaotic Brillouin optical correlation domain analysis with more than one million resolving points

Abstract

.We propose and experimentally demonstrate a long-range chaotic Brillouin optical correlation domain analysis by employing an optimized time-gated scheme and differential denoising configuration, where the number of effective resolving points largely increases to more than one million. The deterioration of the chaotic Brillouin gain spectrum (BGS) and limitation of sensing range owing to the intrinsic noise structure, resulting from the time delay signature (TDS) and nonzero background of chaotic laser, is theoretically analyzed. The optimized time-gated scheme with a higher extinction ratio is used to eliminate the TDS-induced impact. The signal-to-background ratio of the measured BGS is enhanced by the differential denoising scheme to furthest remove the accumulated nonzero noise floor along the fiber, and the pure chaotic BGS is ulteriorly obtained by the Lorentz fit. Ultimately, distributed strain sensing along a 27.54-km fiber with a 2.69-cm spatial resolution is experimentally demonstrated, and the number of effective resolving points is more than 1,020,000.

High-Spatial-Resolution Dynamic Strain Measurement Based on Brillouin Optical Correlation-Domain Sensors

“…Therefore, a 100 m SMF was added to the single feedback structure of the chaotic laser to increase the external feedback delay time, which caused the position of the TDS to be outside the FUT, eliminating the limitation of the TDS on the dynamic strain range. In order to further improve the SNR of the system, in 2023, a long-range chaotic BOCDA system based on optimized time-domain gating and differential denoising techniques was proposed [62]. Finally, distributed strain sensing with an SR of 2.69 cm was achieved along the 27.54 km measurement range, and the number of resolving points was more than 1,020,000, providing a method for high-performance DOFSs.…”

“…For 3, there is a trade-off problem between the high accuracy or wide range and fast measurement. In order to achieve high-speed and real-time measurement, especially of dynamic strain caused by vibration, fast Brillouin DOFSs based on fast-sweep [39][40][41][42][43][44][45][46][47][48][49][50][51][52], sweep-free [53][54][55], and slope-assisted [56][57][58][59][60][61][62][63][64][65][66][67][68][69][70][71] methods have been proposed.…”

Accurate estimation of modulation amplitude in Brillouin optical correlation-domain reflectometry based on Rayleigh noise spectrum

“…Among the various approaches designed for distributed measurements, correlation-domain techniques are distinguished by their high spatial resolution and random accessibility to measurement points, setting them apart from traditional time-domain 6 – 9 and frequency-domain methods 10 , 11 . Brillouin optical correlation-domain sensing encompasses two major configurations: Brillouin optical correlation-domain analysis (BOCDA) 12 – 17 , which leverages stimulated Brillouin scattering via the interaction of counter-propagating pump and probe lights with acoustic waves, and Brillouin optical correlation-domain reflectometry (BOCDR) 18 – 25 , which relies on spontaneous Brillouin scattering and allows single-end accessibility. This paper focuses specifically on the BOCDR technique.…”

Guideline for improving spatial resolution in direct-modulation Brillouin optical correlation-domain reflectometry

“…1) Notable methods include Brillouin optical time-domain reflectometry (BOTDR) [2][3][4] and analysis (BOTDA), [5][6][7][8] Brillouin optical frequency-domain reflectometry (BOFDR) 9) and analysis (BOFDA), 10) and Brillouin optical correlation-domain reflectometry (BOCDR) [11][12][13][14][15][16][17][18][19] and analysis (BOCDA). 20,21) Here, we focus on BOCDR, which achieves high spatial resolution by injecting light into a single end of the fiber under test (FUT).…”