Spatio-temporal joint oversampling-downsampling technique for ultra-high resolution fiber optic distributed acoustic sensing

• DOI: 10.1364/oe.455747
• Publication Date: 2022-07-21T12:00:08Z
• Authors: Hao Li; Cunzheng Fan; Zhengxuan Shi; Baoqiang Yan; Junfeng Chen; Zhijun Yan; Deming Liu; Perry Shum; Qizhen Sun
• Keywords: Oversampling; Upsampling

In order to suppress the noise of coherent fiber distributed acoustic sensing (DAS) system, spatio-temporal joint oversampling-downsampling technique is proposed. The spatial oversampling used for artificially dense sampling, whose spacing far less than target resolution. Then downsampling performed by average multiple differential sub-vectors utilized reduce influence vectors, which could completely eliminate interfere fading without increasing any system complexity and introducing crosstalk. Meanwhile, temporal analyzed from perspective theory simulation, demonstrating that floor will decrease with increase coefficient. carried out expand distribution bandwidth ensure correct quantization frequency. phase reconstruction recover out-of-band noise. experimental results prove inversely correlated spatiotemporal factors. strain resolution DAS proposed scheme can reach 2.58pε/√Hz@100Hz-500Hz 9.47pε/√Hz@10Hz under condition DC-500Hz bandwidth, as well probability large-noise channels greatly reduced 44.32% 0%. Moreover, demodulated SNR dynamic signal improved 20.8dB compared traditional method. Without crosstalk, optimized 8dB lower averaging technique. Based on method, high-performance has significant competitiveness in applications demand high-precision high-sensitivity, such passive-source seismic imaging VSP exploration.