A mechanism of creating a Newton's cradle (NC) in the form of a chain of solitons is proposed for understanding fission of higher-order soliton in optical fibers caused by higher-order dispersion. After the transformation of the initial Nsoliton into a chain of fundamental quasi-solitons, the tallest one travels along the chain through elastic collisions with other solitons, and then escapes, while the other solitons remain in a bound state. Multiple releases of solitons take place if N is sufficiently large. The NC effect is robust against inclusion of the Raman and self-steepening terms.
We study truncated Airy pulses launched into an anomalous dispersion domain of a fiber with strong positive third order
dispersion. The pulse quickly reaches the focal point, and then it undergoes a mirror transformation and continues to
propagate with the acceleration in the opposite direction. At the focal point all of the light pulse energy is concentrated in
a very narrow temporal slot, exhibiting an intriguing pulse compression technique. When both dispersion terms act on
the pulse, the focal point extends to a finite area of spreading of the truncated Airy pulse. The size of the area depends on
the relative strength of the TOD term relative to its second-order counterpart. After this area, the pulse reemerges again
and continues its evolution mirror-transformed. A full exact analytical description of pulses dynamics is developed and
verified with direct numerical simulations.
We consider a long fiber-optic link consisting of alternating dispersive and nonlinear segments, i.e., a split-step model (SSM). Passage of a soliton through one cell of the link is described by an analytically derived map. Multiple numerical iterations of the map reveal that, at values of the system's stepsize (cell's size) L comparable to the pulse's dispersion length ZD, SSM supports stable propagation of pulses which almost exactly coincide with fundamental solitons of the corresponding averaged NLS equation. However, in contrast with the NLS equation, the SSM soliton is a strong attractor, i.e., a perturbed soliton rapidly relaxes to it, emitting some radiation. If the initial amplitude of the pulse is too small, it turns into a breather, and, below a certain threshold, it quickly decays into radiation. If L is essentially larger than ZD, the pulse rapidly rearranges itself into another one, with nearly the same area but essentially smaller energy. At L still larger, the pulse becomes unstable, with a complex system of stability windows found inside the unstable region. Moving solitons are generated by "pushing" them with a frequency shift, which makes it possible to consider collisions between solitons in a two-channel model emulating the WDM regime of data transmission in a communication line. We conclude that the collisions are strongly inelastic if they take place inside the nonlinear section of the system, and the solitons pass through each other without interaction if they collide inside the linear section.