Modeling of Four-Wave Mixing in Optical Multiplexing Networks with Wavelength Division Multiplexing

The paper presents the results of numerical experiments on modeling the propagation of signals with wavelength division multiplexing in G.652 and G.655 optical fibers taking into account both linear and nonlinear effects. The distribution of the components generated through four-wave mixing for different number of channels wavelength division multiplexing system was investigated in MATLAB application program package. It was shown that in the region of the operating frequency range, the distribution of non-degenerate combination frequency components has a peak at the central frequencies of the spectral range, and the combination frequencies of degenerate kind are distributed uniformly over the entire frequency range. At the same time, there are more non-degenerate combination frequencies. The ratio of the number of non-degenerate combination frequencies to the number of degenerate combination frequencies increases with the growth of the number of channels in a wavelength division multiplexing system. The OptiSystem software package developed by Optiwave Systems Inc. was used to investigate the process of four-wave mixing occurrence. In the used computer models, the signal transmitted through the fiber optic transmission system was generated by a random sequence generator in RZ or NRZ code. The simulation result is obtained by spectrum analyzers at the output of the optical fiber. The dependence of Q-factor values on the frequency channel spacing and on the optical fiber length was investigated. It was shown that increasing the frequency channel spacing allows reducing the level of components generated through four-wave mixing. The values of the frequency channel spacing were obtained, at which the Q-factor has values acceptable for modern fiber-optic transmission lines.