The Study Of Nonlinear Effects Estimation Method Within Frequency Domain In Superchannel Systems

The development of information technology has brought a surge of capacity.The channel spacing of wavelength division multiplexing system is becoming more and more less.Therefore superchannel system becomes the research hot spot.Very high speed,very large capacity and very long distance are the trends of future communication.It calls for new requirements to the performance of the transmission network.Optical amplifier,coherent detection and digital signal processing technology perfectly compensate the fiber linear damage.Thus,in order to improve the system performance,it is necessary to do research on optical fiber nonlinear effects.In this paper,the research content is based on nonlinear effects estimation method within frequency domain in superchannel systems,mainly including:first,based on polarization multiplexing single channel compensated system simulation platform,study the effects of different system parameters on the theory.Acquire the simulation nonlinear noise power spectral density using the minimum mean square error algorithm and then compare it with the theoretical calculation results to analyze the application and accuracy of the theory;second,based on polarization multiplexing multi-channel uncompensated system simulation platform,study the effects of different system parameters on the application and accuracy of the theory;third,based on polarization multiplexing multi-channel uncompensated Nyquist system simulation platform,study the relationship between system nonlinear noise power and number of channel multiplexing under fixed total transmission bandwidth.Through amounts of simulation,research findings are as follows:First of all,ordinary link simulation results are not consistent with theoretical predictions.The reason mainly is that common system is not easy to meet the assumption of gaussian noise model,ie,the distribution of the signal is gaussian;Secondly,an amount of pre-dispersion can disrupt the distribution of the signal to be gaussian.Simulation results are in good agreement with theoretical predictions under different system parameters;Lastly,system nonlinear noise power gets its minimum in 40-channel system under fixed total transmission bandwidth and other uniform system parameters.Therefore signal-to-noise-ratio is the highest and the performance is the best.In this paper,research on the estimation of system nonlinear noise can provide valuable reference to subsequent restraint and compensation.