Fig. 2: Sensing performance of TABS.
From: High-spatiotemporal-resolution distributed Brillouin sensing with transient acoustic wave
a Theoretical acoustic wave temporal envelope (real part) at the BFS. The inset compares theoretical BGSs between SAW and TAW when energy accumulation time is 7 ns. Conv. conventional, n.u. normalized unit. Theoretical (b) intrinsic (int.) measurement ranges and (c) spatial resolutions across different effective pulse widths (wp) and Brillouin gain ratio frequency spacings (∆fDS). d Required SNR to achieve the target spatial resolutions and measurement ranges with an uncertainty (δf) of less than 3 MHz. Here, ∆fDS under different pulse widths are adjusted to maintain the same intrinsic linear region of 200 MHz. Meas. measurement, fr relative frequency. e Experimental setup, the detailed introduction is listed in Materials and methods, and Supplementary Section 1. f Comparison of acoustic wave temporal envelopes (real part) between theory and experiment. fr relative frequency, Theor. theoretical, Exp. experimental. g Similarity between theoretical and experimental acoustic wave temporal envelopes (real part), with the inset showing the acoustic wave spectrum at the lowest similarity point. h Measured Brillouin gain ratio spectra, where the light orange area indicates the linear region (i.e., measurement range). i Measurement uncertainty distribution along the fiber, which consists of two fiber sections with lengths of 10 km and 39.25 km, and BFSs of 10.8 GHz and 10.82 GHz, respectively. T0 intermediate temperature. j Measurement uncertainties at 35 km and 49.25 km under different frequency offsets. Measured static temperature variation (∆T) distributions for determining the (k) spatial resolution and (l) extreme sensing capability. In (l), the signals in 15-times measurements are overlapped together for verifying the repeatability in the extreme condition. m Measured sensor dynamic response. n Detailed BFS variation at z1, z2, and z3 positions shown in (m)
