[4] DONG Y K, CHEN L, BAO X Y. Time-division multiplexing-based BOTDA over 100 km sensing length[J]. Optics Letters, 2011, 36(2): 277-279.
[6] RAAB T, REINSCH T, ALDAZ C, et al. Real-time well-integrity monitoring using fiber-optic distributed acoustic sensing[J]. Spe Journal, 2019, 24: 1997-2009.