Application of optimization methods to minimize noise in quantum key distribution systems integrated into fiber-optic communication lines using dense wavelength division multiplexing

摘要

This study examined the applicability of the simulated annealing optimization algorithm to the search for optimal configurations of quantum and information channels required for a successful quantum key distribution session considering grids with different frequency spacings between channels, such as 12.5, 25, 50, and 100 GHz. Aim of study. This study was aimed at optimization of a search for configurations of quantum and information channels for a grid corresponding to dense wavelength division multiplexing standards using optimization methods based on analysis of the channel noise effect on quantum key distribution sessions and investigation of these methods. Method. Naturally, quantum signal powers are significantly lower than those of classic signals. Therefore, noise from information channels for a configuration where they propagate in the same fiber with quantum channels results in considerable reduction of quantum key distribution system performance. This problem can be mitigated by reducing the noise level in the channel via the selection and use of an optimal spectral channel allocation. The search for such channel allocation schemes, which are further referred to as configurations, can be implemented via several methods, such as the educated guess method and the approach entailing optimization using the simulated annealing optimization algorithm, which are the subjects of this study. The results obtained using this method were compared with similar results obtained using the educated guess method. Descriptions of the methods and their interpretation for the context of the objectives of the study are presented together with mathematical models for calculation of noise resulting from spontaneous Raman scattering, four-wave mixing, and linear channel crosstalk. Optimal allocation schemes of quantum and information channels in the grid with dense wavelength division multiplexing (configurations) obtained using the two methods are described. The configurations