Polarization Effects in Bent Uncoupled-Core Multicore Optical Fibers

This work presents a thorough investigation, both experimental and theoretical, of the polarization effects of uncoupled multi-core fibers (UMCFs) under bending, focusing on a four-core configuration. An integrated modeling framework based on Jones matrix formalism, coupled-mode theory, and photoelastic analysis is developed to predict the nonlinear variations of birefringence induced by bending. The use of polarization-sensitive reflectometry for experimental validation confirms that even small bends lead to significant changes in the refractive index profile, resulting in increased polarization-dependent effects. The magnitude of birefringence induced by bending is shown to vary with the orientation of each core, reflecting the interplay between intrinsic bands and extrinsic effects due to mechanical loading. These results confirm the proposed model and provide a practical guide for mitigating bending effects in high-performance optical sensing and telecommunications, leading to an improved design and performance of next-generation optical networks.