Design and optimization of weakly coupled multi-core fiber

In order to achieve comprehensive, highly efficient, and multi-objective precise optimization of fiber structural parameters and further enhance the transmission capacity of optical communication systems, a homogeneous weakly coupled seven-core fiber based on trench-assisted structures is designed. Particle Swarm Optimization (PSO) is introduced to replace traditional empirical designs or local scanning methods. First, a multi-objective fitness function incorporating constraints such as dispersion, cutoff wavelength, effective mode field area, and coating loss is established. Then, the algorithm performs a global search to precisely determine the optimal structural parameters under standard dimensional constraints. Simulation results demonstrate that with a fiber core pitch of 45 μm, the optimized fiber achieves an ultra-low inter-core crosstalk of below −90 dB/km at a wavelength of 1550 nm. This design scheme not only effectively resolves the conflict between crosstalk suppression and spatial utilization in multi-core fibers but also proves the efficiency and reliability of the PSO algorithm in complex fiber structural design, providing an important theoretical basis and technical support for the research and manufacturing of ultra-large-capacity optical communication systems.