A passive correlated fiber loop ringdown (FLRD) system based on an amplified spontaneous emission (ASE) source is proposed and experimentally demonstrated for macro-bending measurement. Due to the randomness of spontaneous emission, the autocorrelation coefficient of ASE has an extremely narrow FWHM (0.114 ns), which allows shorter fiber loop and higher sensitivity. The experimental results show that our system with a fiber length of 2.1 m can identify the bending within tens of nanoseconds. When the bending diameter remains 2.5 cm, the sensitivity of bending turns reaches ${0.0017}\;{{\rm ns}^{- 1}}/{\rm turn}$. This system provides an effective solution for fast bending fault diagnosis.

中文翻译：

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基于具有ASE源的相关FLRD系统的宏弯测量

提出了一种基于放大自发辐射（ASE）源的无源相关光纤环路振铃（FLRD）系统，并通过实验证明了该系统可用于宏观弯曲测量。由于自发发射的随机性，ASE的自相关系数具有极窄的FWHM（0.114 ns），从而可以缩短光纤环路并提高灵敏度。实验结果表明，我们的纤维长度为2.1 m的系统可以在数十纳秒内识别出弯曲。当弯曲直径保持2.5 cm时，弯曲匝的灵敏度达到$ {0.0017} \; {{\ rm ns} ^ {-1}} / {\ rm turn} $。该系统为快速弯曲故障诊断提供了有效的解决方案。