Propagation Dynamics of Dark Pulses in Optical Fiber Links

The authors investigate nonlinear evolution of a dark pulse allocated within an arbitrary background bright pulse upon propagation in telecom optical fibers. For the first time was revealed that owing to a phenomenon partially similar to the modulation instability, a single dark pulse can evolve into a specific pulse structure - an ordered cluster of bound bright and dark pulses, when propagating in anomalous-dispersion fibers. It was shown that energy of the background pulse can be mostly transferred to the burst of bright and dark pulses under certain conditions. This evolution is governed mainly by such initial parameters as the background pulse peak power and the dark pulse duration. It can be considered as a limiting factor for fiber transmission of arbitrary optical waveforms, on the one hand, and as a promising method for ultrashort pulse bursts generation, on the other hand. The obtained bursts feature an ultrahigh (sub-THz) intraburst pulse repetition rate.