Soliton Molecules and Multisoliton States in Ultrafast Fibre Lasers: Intrinsic Complexes in Dissipative Systems

Abstract

Featured Application: High-capacity telecommunication, advanced time-resolved spectroscopy, self-organization and chaos in dissipative systems. Abstract:Benefiting from ultrafast temporal resolution, broadband spectral bandwidth, as well as high peak power, passively mode-locked fibre lasers have attracted growing interest and exhibited great potential from fundamental sciences to industrial and military applications. As a nonlinear system containing complex interactions from gain, loss, nonlinearity, dispersion, etc., ultrafast fibre lasers deliver not only conventional single soliton but also soliton bunching with different types. In analogy to molecules consisting of several atoms in chemistry, soliton molecules (in other words, bound solitons) in fibre lasers are of vital importance for in-depth understanding of the nonlinear interaction mechanism and further exploration for high-capacity fibre-optic communications. In this Review, we summarize the state-of-the-art advances on soliton molecules in ultrafast fibre lasers. A variety of soliton molecules with different numbers of soliton, phase-differences and pulse separations were experimentally observed owing to the flexibility of parameters such as mode-locking techniques and dispersion control. Numerical simulations clearly unravel how different nonlinear interactions contribute to formation of soliton molecules. Analysis of the stability and the underlying physical mechanisms of bound solitons bring important insights to this field. For a complete view of nonlinear optical phenomena in fibre lasers, other dissipative states such as vibrating soliton pairs, soliton rains, rogue waves and coexisting dissipative solitons are also discussed. With development of advanced real-time detection techniques, the internal motion of different pulsing states is anticipated to be characterized, rendering fibre lasers a versatile platform for nonlinear complex dynamics and various practical applications.

MXene: two dimensional inorganic compounds, for generation of bound state soliton pulses in nonlinear optical system

“…On the contrary, when the two sub-pulses are far apart, they attract each other and finally reach the equilibrium distance. This phenomenon can also be called soliton molecules pulse because it is similar to a chemical molecule [38][39][40][41]. MXene as a novel 2D material has been investigated recently.…”

Harnessing a multi-dimensional fibre laser using genetic wavefront shaping

“…5f , different numbers of coexisting pulses are generated, i.e., one to five pulses. Please note that the maximum number of coexisting pulses is mainly determined by the pump power level, which can be attributed to the energy quantization effect of dissipative optical solitons 37 – 39 . One of the potential applications of multi-pulse mode-locking is the generation of high-repetition-rate pulses through harmonic mode-locking.…”

Multibound Soliton Formation in an Erbium-Doped Ring Laser With a Highly Nonlinear Resonator

“…4(a)) evidently shows highcontrast intensity fringes (~18 dB) that indicate a stable and strong coherent connection between the ultrashort pulses and fixed coherent phase difference in the temporal domain between several identical pulses [1]. The lack of symmetry could be attributed to the influence of high-order dispersion and the phase difference of π/2 between bound solitons [27]. The constant period of the sharp intensity fringes indicates the presence of several bound pulses with a stable time separation between them [15].…”