Newton's cradles in optics: FromN-soliton fission to soliton chains

Abstract

A mechanism for creating a Newton's cradle (NC) in nonlinear light wavetrains under the action of the third-order dispersion (TOD) is demonstrated. The formation of the NC structure plays an important role in the process of fission of higher-order (N -) solitons in optical fibers. After the splitting of the initial N -soliton into a nonuniform chain of fundamental quasi-solitons, the tallest one travels along the entire chain, through consecutive collisions with other solitons, and then escapes, while the remaining chain of pulses stays as a bound state, due to the radiation-mediated interaction between them. Increasing the initial soliton's order, N , leads to the transmission through, and release of additional solitons with enhanced power, along with the emission of radiation, which may demonstrate a broadband supercontinuum spectrum. The NC dynamical regime remains robust in the presence of extra perturbations, such as the Raman and self-steepening effects, and dispersions terms above the third order. It is demonstrated that essentially the same NC mechanism is induced by the TOD in finite segments of periodic wavetrains (in particular, soliton chains). A strong difference from the mechanical NC is that the TOD-driven pulse passing through the soliton array collects energy and momentum from other solitons. Thus, uniform and non-uniforms arrays of nonlinear wave pulses offer an essential extension of the mechanical NC, in which the quasi-particles, unlike mechanical beads, interact inelastically, exchanging energy and generating radiation. Nevertheless, the characteristic phenomenology of NC chains may be clearly identified in these nonlinear-wave settings too.

The analysis of all-optical logic gates based with tunable femtosecond soliton self-frequency shift

“…There exists a Satsuma-Yajima regime [30], when the initial N-soliton is split into N distinct fundamental solitons. The fission is governed by the Newton's cradle mechanism [37] in the case of TOD, which explains that fission of N-solitons would emit strong dispersive radiation. The self-steepening effects would decelerate slightly the fundamental soliton SFS if pulse width is greater than 30fs soliton width [36,38].…”

Higher-order-effects management of soliton interactions in the Hirota equation

“…Furthermore, if the Raman SFS is stronger, optical rogue waves appear and disappear from nowhere, the result from of soliton interactions [29]. In the absence of Raman effects, TOD-induced fission can generate Newton's cradle in nonlinear light wave trains by soliton interactions [30]. The methods of study mentioned above are numerical simulation and experiment.…”

Multisoliton Newton's cradles and supersolitons in regular and parity-time-symmetric nonlinear couplers

“…One recently elaborated example is a possibility to use arrays of optical solitons, in dissipative two-dimensional [54] and conservative one-dimensional [55] setups alike, for building optical counterparts of the Newton's cradle (NC), which are well known in mechanics and molecular dynamics [56][57][58][59], and "supersolitons", i.e., self-supporting dislocations propagating in chains of individual solitons. Previously, "supersolitons" were experimentally realized and theoretically studied in chains of fluxons populating long periodically inhomogeneous Josephson junctions [60,61], and predicted in binary Bose-Einstein condensates (BECs), with attractive interactions in each component and repulsion between them [62].…”