Breather Molecular Complexes in a Passively Mode‐Locked Fiber Laser

Abstract

Breathing solitons are nonlinear waves in which the energy concentrates in a localized and oscillatory fashion. Similarly to stationary solitons, breathers in dissipative systems can form stable bound states displaying molecule-like dynamics, which are frequently called breather molecules. So far, the experimental observation of optical breather molecules and the real-time detection of their dynamics are limited to diatomic molecules, that is, bound states of only two breathers. In this work, the observation of different types of breather complexes in a mode-locked fiber laser: multibreather molecules, and molecular complexes originating from the binding of two breather-pair molecules or a breather pair molecule and a single breather is reported. The intermolecular temporal separation of the molecular complexes attains several hundreds of picoseconds, which is more than an order of magnitude larger than that of their stationary soliton counterparts and is a signature of long-range interactions. Numerical simulations of the laser model support the experimental findings. Moreover, nonequilibrium dynamics of breathing solitons are also observed, including breather collisions and annihilation. This work opens the possibility of studying the dynamics of many-body systems in which breathers are the elementary constituents.

Nonlinear Wave Molecules for the Lakshmanan–Porsezian–Daniel Equation in Nonlinear Optics and Biology

“…Such molecule structures have been experimentally observed in a passively mode-locked fibre laser. [73] For further exploration of the breather molecules, we next explain the formation mechanism of the breather molecules in terms of the nonlinear superposition principle. From above, we know that the SWC and PWC of each atom in the breather molecule hold different characteristic directions, which can be visualized in Figure 5a.…”

“…They have revealed the dynamics of the breather molecules and obtained multi-breather molecules along with breather molecule complexes in a passively mode-locked fiber laser. [72,73] Considering that the higher-order effects can induce novel nonlinear excitations which are absent in the NLS equation, it is natural to expect more kinds of nonlinear wave molecules to appear in higher-order NLS equations.…”

Breathing Dissipative Soliton Molecule Switching in a Bidirectional Mode‐Locked Fiber Laser

“…[ 33,34 ] In addition to stationary soliton molecules, there are also dynamic soliton molecules, among which the time interval or phase difference between individual solitons changes over time, and breathing soliton molecules (BSMs), that experience periodic spectra and temporal evolutions. [ 35–37 ]…”

“…[33,34] In addition to stationary soliton molecules, there are also dynamic soliton molecules, among which the time interval or phase difference between individual solitons changes over time, and breathing soliton molecules (BSMs), that experience periodic spectra and temporal evolutions. [35][36][37] Despite the stable breathing dynamics of soliton molecules that have been reported previously in undirectional lasers, the most exotic dynamic evolution of BSMs is still largely unexplored, particularly in the normal dispersion bidirectional mode-locked fiber laser, which is an excellent platform for dissipative solitons involving rare dynamics. In addition, the bidirectional mode-locked fiber laser is regarded as a novel light source…”

Real‐Time Observation of Double‐Hopf Bifurcation in an Ultrafast All‐PM Fiber Laser

“…202100646 Only recently, the breathing-like dynamics has also been demonstrated in ultrafast fiber lasers thanks to the development of the real-time dispersive Fouriertransform (DFT) technique. [5] Such behavior is independent of the signs of dispersion of the fiber lasers, and can be found in cavities exhibiting either net anomalous or net normal [6][7][8][9][10][11][12][13][14][15] dispersion. Note that in all previous experiments, the authors have observed breathers or pulsations characterized by a single frequency, that can be superimposed on periodn bifurcations (period doubling, period tripling, etc.…”