Підвищення ефективності пасивних оптичних інфокомунікаційних мереж доступу

Abstract

The basic methods of optical modulation of multichannel signals consisting of frequency-separated channels, the basics of frequency multiplexing of channels, methods of photo-detection, methods of transmitting duplicate multichannel signals on one fiber are considered. The advantages of frequency division of channels in passive optical access networks over time division technology are revealed. It is shown that the use of multilevel digital modulation formats in the formation of frequency channels allows to increase the speed of signal transmission in the network. The results of simulation modeling of the optical modulation process in optoelectronic components with direct and external modulation and taking into account the influence of the nonlinear characteristics of these components on the signal quality indicators allow you to select modulation modes to ensure the required signal quality. The approximate formulas of the signal quality indicators, which are consistent with the simulation results, are presented. The expediency of using an external modulator with a higher bandwidth compared to the laser diode for direct radiation modulation is shown. The circular topologies for the organization of the supporting networks and the PON-tree tree architecture are considered. Structural diagrams of the switching units of the channels intended for the user of the end devices and principles of functioning of the networks are developed. The PON bandwidth of the frequency division of channels with the NG-PON2 network is compared.