Design of Homogeneous Trench-Assisted Multi-Core Fibers Based on Analytical Model

We present a design method of homogeneous trench-assisted multicore fibers (TA-MCFs) based on an analytical model utilizing an analytical expression for the mode coupling coefficient between two adjacent cores. The analytical model can also be used for crosstalk (XT) properties analysis, such as XT reduction amount versus trench width, trench depth, and other fiber structural parameters as compared with normal step-index MCFs. Furthermore, the model can be used to search for core positions for further XT reduction in nonclose-packed structures. For instance, we show that a dual-ring structure is the quasi-optimum core layout starting from an one-ring structured 12-core fiber. Based on the analytical model, a square-lattice structured 24-core fiber and a 32-core fiber are designed both for propagation-direction interleaving (PDI) and non-PDI transmission schemes. The proposed model provides a powerful tool for designing high-count homogeneous TA-MCFs.