An inline fiber sensor for simultaneous measurement of curvature and temperature based on anti-resonant (AR) effect combined with multimode interference (MMI) is proposed and experimentally demonstrated. The sensing structure is simply formed by embedding a section of multimode fiber (MMF) and glass capillary between single-mode fibers (SMF). Thence the multimode interference (MMI) pattern with dips and the AR effect spectrum with the loss valleys at the resonance wavelengths can be observed on the optical spectrum analyzer (OSA). A curvature sensitivity of -9.25 dB/m-1 with almost unchanged wavelength can be achieved by intensity demodulation at an AR valley. And a temperature sensitivity of 30 pm/°C with a tiny intensity sensitivity -0.079 dB/°C is obtained by wavelength demodulation at a MMI dip. Different demodulation mechanisms enable our sensors to discriminate curvature and temperature. Moreover, the advantages such as repeatability of fabrication, robust structure and cost-effectiveness, further benefit its practical sensing applications.

中文翻译：

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基于反谐振效应结合多模干扰的曲率和温度传感器


提出并通过实验证明了一种基于反谐振（AR）效应与多模干涉（MMI）相结合的同时测量曲率和温度的在线光纤传感器。传感结构简单地通过在单模光纤（SMF）之间嵌入一段多模光纤（MMF）和玻璃毛细管而形成。因此，可以在光谱分析仪 (OSA) 上观察到在谐振波长处具有凹陷的多模干涉 (MMI) 图案和具有损耗谷的 AR 效应光谱。通过 AR 谷处的强度解调，可以在波长几乎不变的情况下实现 -9.25 dB/m-1 的曲率灵敏度。通过 MMI 下陷处的波长解调获得了 30 pm/°C 的温度灵敏度和 -0.079 dB/°C 的微小强度灵敏度。不同的解调机制使我们的传感器能​​够区分曲率和温度。此外，制造的可重复性、坚固的结构和成本效益等优点进一步有利于其实际传感应用。