Cladding shape fitting model for multi-core fibers using a Lamé curve

Herein, we propose a measurement technique for modeling the cladding cross-section of multi-core fibers (MCFs) with a generalized ellipse (superellipse; Lamé curve). In contrast to conventional ellipse fitting, the Lamé curve model reproduces square-like non-circular claddings typical of many MCFs. Evaluation of several MCF cross-sectional images reveals that the proposed Lamé fitting reduces the root mean square residual by 39.6%, thereby improving geometric accuracy. This quantitative advantage indicates that Lamé curve fitting is valuable for defining cladding non-circularity and center location in MCF standardization and enhancing alignment precision in practical connector and splice applications.