212-km ultra-long-distance hybrid Φ-OTDR/BOTDR based on remotely pumped optical amplification
Yanyang Lei, Xiaohui Tang, Meng Xia, Taofei Jiang, Shuaiqi Liu, Tianfu Li, Dexin Ba, Yongkang Dong
Abstract
In this paper, we propose and demonstrate a 212 km ultra-long-distance hybrid distributed optical fiber sensing (DOFS) system capable of simultaneously measuring vibration and strain/temperature along the sensing fiber. This is achieved by integrating phase-sensitive optical time-domain reflectometry (Φ-OTDR) and Brillouin optical time-domain reflectometry (BOTDR) into a single interrogator. The extended sensing range is realized through the use of wavelength division multiplexing, time division multiplexing, co-pumped distributed Raman amplification, and remotely pumped optical amplification technologies. The system achieves a 20 m spatial resolution for vibration sensing and a 50 m resolution for strain/temperature sensing, with strain/temperature measurement accuracy reaching 4.3 MHz. Notably, the single-end operation and simplified system architecture make this solution highly suited for industrial on-site applications. To our knowledge, this is the longest measurement range reported for hybrid DOFS systems without the aid of active repeaters or bi-directional distributed amplification techniques.