A Novel Core Allocation in Heterogeneous Step-Index Multi-Core Fibers With Standard Cladding Diameter

We numerically reveal the feasibility of designing multi-core fibers (MCFs) with the simple step-index (SI) profile within the standard 125- μ m cladding diameter. We show that the standard cladding diameter enables us to incorporate five identical cores for C-band operation, and the number of cores can be further increased with the heterogeneous core arrangement. We then propose a novel method of allocating the non-identical cores in heterogeneous MCFs (Hetero-MCFs), where the crosstalk (XT) and critical bending radius ( R pk ) are improved comparing to that of Hetero-MCFs designed by the conventional method. These new types of step-index MCFs (SI-MCFs) with standard cladding diameter have potential application in the space-division multiplexing (SDM) systems.