In this letter, we propose a novel bamboo-shaped interference sensor based on multistage photonic-band gap microstructured fiber (PBG-MF) and single-mode fiber (SMF) to build the cascaded Fabry-Perot interferometer (FPI). Due to the honeycomb space inside the PBG-MF, a higher extinction ratio (ER) is obtained in the reflection spectrum of the interferometer, which is conducive to improving the detection limit (DL) and resolution of the sensor. The bending direction can be identified by the structure proposed in this letter. Maximum curvature sensitivity is 991 pm/m ⁻¹ in the convex direction. Maximum curvature sensitivity is −1118 pm/m ⁻¹ in the concave direction. The sensor has the advantages of small size, high sensitivity, and high package stability. It is particularly suitable for ultra-short distance curvature sensing, such as the joints of the human body.

中文翻译：

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一种新型的微结构纤维曲率测量竹形传感器

在这封信中，我们提出了一种基于多级光子带隙微结构光纤（PBG-MF）和单模光纤（SMF）的新型竹形干涉传感器，以构建级联的Fabry-Perot干涉仪（FPI）。由于PBG-MF内部的蜂窝状空间，在干涉仪的反射光谱中获得了更高的消光比（ER），这有利于提高检测极限（DL）和传感器的分辨率。弯曲方向可以通过这封信中提出的结构来确定。凸方向上的最大曲率灵敏度为991 pm / m ^-1。最大曲率灵敏度为-1118 pm / m ^-1在凹方向上。该传感器具有体积小，灵敏度高和封装稳定性高的优点。它特别适用于超短距离曲率感测，例如人体的关节。