Spatial Density and Splicing Characteristic Optimized Few-mode Multi-core Fiber

Few-mode fiber design suitable for long-haul dense space division multiplexing (SDM) transmission is proposed, where the spatial density and the splicing characteristics of the fiber is optimized. We numerically investigate the impact of the number of modes per core in a multi-core structure on the total number of spatial channels possible and the splice loss property. It is shown that increased number of mode per core enables us to improve the spatial density while maintaining feasible splice-induced differential modal attenuation. We then successfully fabricate a 10-mode 12-core fiber with a cladding diameter of 217 μm, that achieves a relative core multiplicity factor (RCMF) of 101.7 and maximum number of spatial channels among the possible few-mode multi-core fiber designs with a cladding diameter of less than 250 μm. Experiments confirm that its splice-induced differential modal attenuation characteristics were better than those of previously reported 114-spatial-channel fiber.