Synchronous azimuth calibration of helical multicore fibers in shape sensing

Helical multicore fibers offer great potential for optical fiber shape sensing due to space division multiplexing capability and high strain measurement accuracy. However, dynamic azimuthal variations introduced by fiber drawing can lead to significant reconstruction errors. We propose a synchronous azimuth calibration method that decouples the phase-azimuth relationship of strain curves and performs dynamic calibration combined with the optimization algorithm. Experimental results show that the proposed method effectively compensates for azimuthal deviations along the fiber, improving the average Euclidean distance accuracy by 34.89%, thereby enhancing the precision and reliability of optical fiber shape reconstruction.