A NUMERICAL-ANALYTICAL METHOD FOR THE SYNTHESIS OF OPTIMAL IRREGULAR DWDM FREQUENCY PLANS

Abstract

The possibilities of increasing the throughput of fiber-optic transmission systems by using an uneven frequency grid are investigated. In this case, the bandwidth of each channel is selected so that the transmission rate is the same for all channels. In this work, both linear and some nonlinear effects are taken into account, leading to the distortion of the optical pulse. Simulation of nonlinear effects is based on a model in the form of a generalized nonlinear Schrödinger equation. The developed program provides modeling of linear and nonlinear distortions for the DWDM range (from 1460 to 1625 nm). The characteristics of different types of optical fiber are also provided. Non-linear effects are investigated for NZ DSF-type dispersion-shifted fiber. Differential equations are solved by the method of splitting according to physical factors. It is shown that for this type of fiber at distances of 100 km and more, a soliton transmission mode appears. In this case, the frequency band of the soliton regime can reach significant values ​​(up to 5 THz) at typical lengths of the regeneration sections of the order of 100-300 km. A method for calculating the bandwidth of uneven frequency plans is proposed. This method has been tested for a 15 THz band. A specific example of calculations is given for the comparison base in the form of a uniform frequency plan with a single channel bandwidth of 50 GHz. It is shown that optimal non-uniform frequency plans can significantly increase the throughput of DWDM systems: in the given example, approximately 3 times. At the same time, the complexity of the equipment increases slightly