Distributed OTDR-interferometric sensing network with identical ultra-weak fiber Bragg gratings

作者：Chen Wang, Ying Shang, Xiaohui Liu, Chang Wang, Haihu Yu, Desheng Jiang, Gang‐Ding Peng · 发表于：Optics Express · 年份：2015 · DOI：10.1364/oe.23.029038 · 被引用次数：173 · 研究领域：Advanced Fiber Optic Sensors、Photonic and Optical Devices、Mechanical and Optical Resonators

We demonstrate a distributed sensing network with 500 identical ultra-weak fiber Bragg gratings (uwFBGs) in an equal separation of 2m using balanced Michelson interferometer of the phase sensitive optical time domain reflectometry (φ-OTDR) for acoustic measurement. Phase, amplitude, frequency response and location information can be directly obtained at the same time by using the passive 3 × 3 coupler demodulation. Lab experiments on detecting sound waves in water tank are carried out. The results show that this system can well demodulate distributed acoustic signal with the pressure detection limit of 0.122Pa and achieve an acoustic phase sensitivity of around -158dB (re rad/μPa) with a relatively flat frequency response between 450Hz to 600Hz.