The present work deals with a curvature sensor that consists of two segments of asymmetric multicore fiber (MCF) fusion spliced with standard single mode fiber (SMF). The MCF comprises three strongly coupled cores; one of such cores is at the geometrical center of the MCF. The two segments of MCF are short, have different lengths (less than 2 cm each), and are rotated 180° with respect to each other. The fabrication of the sensor was carried out with a fusion splicing machine that has the means for rotating optical fibers. It is demonstrated that the sensor behaves as two SMF–MCF–SMF structures in series, and consequently, it has enhanced sensitivity. The device proposed here can be used to sense the direction and amplitude of curvature by monitoring either wavelength shifts or intensity changes. In the latter case, high curvature sensitivity was observed. The device can also be used for the development of other highly sensitive sensors to monitor, for example, vibrations, force, pressure, or any other parameter that induces periodic or local curvature or bending to the MCF segments.

中文翻译：

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用于方向敏感曲率监测的组合多芯光纤结构

本工作涉及一种曲率传感器，该传感器由两段不对称的多芯光纤（MCF）融合并与标准单模光纤（SMF）熔接而成。MCF包含三个强耦合核心；这样的核心之一是在MCF的几何中心。MCF的两个部分很短，具有不同的长度（每个长度小于2厘米），并且相对于彼此旋转了180°。传感器的制造是使用具有使光纤旋转的装置的熔接机进行的。结果表明，该传感器表现为两个串联的SMF–MCF–SMF结构，因此具有更高的灵敏度。通过监视波长偏移或强度变化，此处提出的设备可用于检测曲率的方向和幅度。在后一种情况下，观察到高曲率灵敏度。该设备还可用于开发其他高度敏感的传感器，以监视例如振动，力，压力或任何其他参数，这些参数会引起MCF段的周期性或局部曲率或弯曲。