Providing the Required Probability of Synchronization Error When Splitting a Fiber-Optic Line into Sections with Decreasing Length in a Quantum Key Distribution System

Abstract

A technique is proposed for dividing a fiber-optic communication line into sections with decreasing length in a quantum key distribution system. A distinctive feature of the proposed method is to provide the required probability of synchronization error. It is noted that an increase in the required number of sections is inversely proportional to a decrease in the probability of a synchronization error at a fixed station spacing. The relationship between the probability of synchronization error and station spacing is determined. So, with an increase in the frequency of generation of dark current pulses at a given value of the probability of synchronization error, the length of the fiber-optic communication line is significantly reduced. Due to the constancy of the signal-to-noise ratio at the upper boundaries of the sections, the probability of synchronization error is provided not worse than the specified value within the entire fiber-optic line.