EVALUATIONS OF THE LIMIT TRANSMISSION SPEED IN THE MAGISTRAL FIBER OPTICAL SYSTEMS

Abstract

The object under study are fiber-optic transmission systems of national-class operators. The length of the regeneration sections is assumed to be approximately 100…500 km. Of fundamental importance is the use of standard fiber. The aim of the article is to obtain estimates of the potential transmission rate for this class of objects. The following are considered as performance indicators: spectral efficiency in narrow-frequency channels, total transmission rate in the entire frequency range, total transmission rate taking into account the length of the regeneration section. The analysis of the values of these indicators for industrial and experimental transmission systems. It is shown that the total transfer rate for actually used systems can reach 8…20 Tbit / s. In this case, a band is used in the S-C-L bands with a total width of the order of 20 THz. Frequency channels have equal width in different frequency plans from 12.5 to 100 GHz. The refinement of the sampling theorem for the dispersion channel is given and it is shown that the transmission rate in such a channel can be significantly lower than the Nyquist speed. A method for calculating the potential transmission rate for systems with a bandwidth of about 200…300 THz is proposed. It is shown that in this case, the transmission rate can be increased by approximately an order of magnitude. The calculations for the frequency plan with an uneven bandwidth of individual channels are presented. In this case, the bandwidth is selected from the condition of equal transmission speeds. At the same time, the transmission speed at a distance of 100 km can theoretically be increased to 500…1500 Tbit / s when using an already laid cable.