To break the π-phase criterion in phase demodulation, POFNet is proposed to fuse the OPD and the phase signal to estimate the unwrapping errors and recover larger phase. The results showcase its superiority performance.
@inproceedings{pofnet_cleo,author={Liu, Zechao and Zheng, Hongkun and Zhu, Chen and Ma, Lingmei},booktitle={2024 Conference on Lasers and Electro-Optics (CLEO)},title={POFNet: Enlarging the Dynamic Range of Phase Demodulation by Signal Fusion},year={2024},volume={},number={},pages={AF2D.7},doi={https://doi.org/doi:10.1364/cleo_at.2024.af2d.7},url={https://opg.optica.org/abstract.cfm?URI=CLEO_AT-2024-AF2D.7},publisher={Optica Publishing Group},}
Paper
Phase correction based SNR enhancement for distributed acoustic sensing with strong environmental background interference
Caiyun Li , Zechao Liu, Yiyang Zhuang, Hongkun Zheng, and 5 more authors
Fiber-optic distributed acoustic sensing (DAS) systems based on phase-sensitive optical time domain reflectometry (Φ-OTDR) measure acoustic waves by demodulating the phase variations of the Rayleigh backscattering (RBS) signals in a sensing optical fiber. However, in harsh environments, strong environmental background interference, coupled with the interference fading of the RBS, would introduce severe distortions in DAS signal that cannot be corrected or even can be worsened by phase unwrapping, thus resulting in low signal to noise ratio (SNR) and even undetectable signal. In this work, a novel method based on trend prediction is proposed to correct the distortions induced by phase unwrapping error around the fading points. The method is further validated in processing the data acquired from a field test performed in ocean environments using a home-built DAS system. By locating and erasing the distortion points, and then detrending, the acoustic signal buried in strong environmental background interference is retrieved with an SNR improvement greater than 10 dB. The results show that the proposed phase correction method can effectively enhance DAS’s SNR for those challenging applications with strong background interference.
@article{aunwrap,title={Phase correction based SNR enhancement for distributed acoustic sensing with strong environmental background interference},journal={Optics and Lasers in Engineering},volume={168},pages={107678},year={2023},issn={0143-8166},doi={https://doi.org/10.1016/j.optlaseng.2023.107678},url={https://www.sciencedirect.com/science/article/pii/S0143816623002075},author={Li, Caiyun and Liu, Zechao and Zhuang, Yiyang and Zheng, Hongkun and Zhu, Chen and Hu, Weiwang and Wang, Jianguo and Ma, Lingmei and Rao, Yun-Jiang},keywords={Fiber-optic distributed acoustic sensing systems (DAS), Phase-sensitive optical time domain reflectometry (φ-OTDR), Unwrapped phase, Interference fading, Large dynamic range, Phase distrotion},}
