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Abstract. This paper works with the simulation of T-CONT

This paper is devoted to the analysis of environmental influences in the optical transmission medium and their impacts on multilevel modulation formats. An attention is focused on main features and characteristics of environmental negative influences of optical fibers. Consequently, principles for appropriate multilevel modulation formats are introduced together with block schemes representing their main functionalities. The created Simulink model for technologies and communications is verified for real conditions in the optical transmission medium. It can allow executing requested analysis for environmental influences on advanced multilevel modulation formats at the signal transmission. Finally, a comparison of considered multilevel modulations is introduced, using constellation diagrams, signal characteristics, eye diagrams and waterfall curves of individual signals.

The Fisher-Snedecor F distribution has been recently proposed as an experimentally verified and tractable turbulence induced fading model (TIFM) for free space optical (FSO) communications. This paper provides outage probability (OP) and higher-order (HO) performance analysis of the product of N independent but not identically distributed (i.n.i.d) Fisher-Snedecor F random variates (RVs). Accurate and closed-form (C-F) expressions for cumulative distribution function (CDF), level crossing rate (LCR) and average fade duration (AFD) of N-Fisher-Snedecor F distribution are successfully derived. The general property of a Laplace approximation approach for evaluation of N-folded complex integral-form (I-F) LCR expressions has been applied. The obtained statistical results are directly related to the performance evaluation of N-hop FSO communication links over weak, moderate and strong atmospheric turbulence conditions.

This paper deals with a modeling of the phase shift keying (PSK) and the possibility of implementing PSK modulations using Mach-Zehnder modulators in the Matlab simulation environment. Next, a simulation of selected multi-level PSK modulations utilizing at the signal transmission in the optical transmission medium is executed. Finally, a comparison of modulated optical signals before and after passing a model of the optical transmission path is introduced, using constellation diagrams, signal characteristics, eye diagrams and waterfall curves of individual signals.

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This paper deals with the integration of polarization multiplexed 16-ary quadrature amplitude modulation format in optical metropolitan networks enhanced with the signal amplification. Before expensive experimental setup or practical testing and demonstration, we prefer creating of appropriate simulation platform for the optical transmission system. A novelty can be found in adjusting, optimizing and construction of the proposed optical system and functional parts for any modulation format used. So, such simulation platform is first introduced along with possibilities for numerical simulations of its optical components - laser and amplifier. By this way, essential noise tolerances for comparison with the data under real conditions are included. Subsequently, there are characterized implementations of terminal devices in detail with a possibility for upgrading to the dual-polarization mode operation. Finally, simulation results from the simulation platform are presented and a discussion about demands for effective exploitation of the polarization multiplexed 16-ary quadrature amplitude modulation in enhanced optical metropolitan networks concludes our contribution.