A simple and efficient numerical method for nonlinear pulse propagation in N-core optical couplers

A set of N-dimension linear-coupled first-order differential equations were solved by a new method, which leads to a very simple iterative scheme. Based on the split-step Fourier technique, a simple and efficient algorithm was developed for analyzing pulse propagation in an N-core linear-coupled nonlinear coupler with the linear mismatch, loss, gain, higher order dispersion, and intermodal dispersion effect. It inherits the advantages of simplicity, flexibility, good accuracy, and relatively modest computing cost of the split-step Fourier method in single fiber.