This paper presents a technique to acquire measurements of curvature, twist and pose for two multi-core fibers; one with straight cores and the other with helical cores. Both the fibers have multiple fiber Bragg grating (FBG) sensors inscribed in the cores and the fibers are placed in known configurations in order to compare their measurement accuracy. For the curvature measurements both the fibers are placed in constant curvature slots; for the twist measurements, a set of twists are applied to each fiber and for the pose measurements the fibers are placed in molds of different shape. The mean curvature errors are 0.22 and 0.13 m${}^{-1}$, in the helical and straight core fiber respectively. For the twist measurement the mean errors are 26.57$°$/m and 146.50$°$/m in the helical and straight core fiber, respectively. Lastly, the pose measurement consists of position and orientation where the orientation is represented in the axis-angle form. The mean position errors are 0.49 and 0.27 mm, the mean axis orientation errors are 0.12$°$ and 0.26$°$ degrees and the mean angle orientation errors are 1.10$°$ and 1.18$°$, for the helical and straight core fiber, respectively. The results show that the twist measurement error is significantly low with the helical core fiber, thus helical core fiber is better suited than straight core fiber for applications where twist measurements are required.

本文提出了一种用于获取两条多芯光纤的曲率，扭曲和姿势测量的技术。一个带有直芯，另一个带有螺旋芯。两种光纤都在纤芯中刻有多个光纤布拉格光栅（FBG）传感器，并且将光纤放置在已知配置中以比较其测量精度。为了进行曲率测量，将两个光纤都放置在恒定曲率的槽中。对于捻度测量，对每根纤维施加一组捻度，对于姿态测量，将纤维置于不同形状的模具中。平均曲率误差为0.22 m${}^{-\mathrm{1个}}$ 和0.13 m${}^{-\mathrm{1个}}$分别在螺旋和直芯光纤中。对于扭曲测量，螺旋和直芯光纤的平均误差分别为26.57度/ m和146.50度/ m。最后，姿势测量由位置和方向组成，其中方向以轴角形式表示。对于螺旋和直芯纤维，平均位置误差分别为0.49mm和0.27mm，平均轴取向误差为0.12度和0.26度，平均角取向误差为1.10度和1.18度。结果表明，螺旋芯光纤的扭曲测量误差非常低，因此在需要扭曲测量的应用中，螺旋芯光纤比直芯光纤更适合。