Generation of single or double parallel breathing soliton pairs, bound breathing solitons, moving breathing solitons, and diverse composite breathing solitons in optical fibers

Interactions of Airy beams in nonlinear media with fourth-order diffraction

We investigate to the best of our knowledge the first time the interactions of in-phase and out-of-phase Airy beams in Kerr, saturable and nonlocal nonlinear media with fourth-order diffraction using split-step Fourier transform method. Directly numerical simulations show that normal and anomalous fourth-order diffractions have profound effects on the interactions of the Airy beams in Kerr and saturable nonlinear media. We demonstrate the dynamics of the interactions in detail. In nonlocal media with fourth-order diffraction, nonlocality induces a long-range attractive force between Airy beams, leading to the formation of stable bound states of both in-phase and out-of-phase breathing Airy soliton pairs which are always repulsive in local media. Our results have potential applications in all-optical devices for communication and optical interconnects, etc.

Symmetrical reversal transmission of Airy pulses in dispersion-managed fiber systems

Based on the dispersion management technology, the transmission characteristics of Airy pulses in optical fiber systems are studied theoretically and numerically. The results show that the group velocity dispersion and third-order dispersion that change periodically along the transmission direction of the optical fiber can prolong the transmission of pulses. Under the action of periodically varying group velocity dispersion, the symmetrical reversal of the Airy pulse can be realized which the shape of the pulse keeps invariable and the tail converses after the inversion. When the periodic third-order dispersion effect is also considered, the periodically symmetrical reversal of the Airy pulse happens and the pulse can be regenerated periodically at the certain transmission distance. Adjusting the parameters of the third-order dispersion, the inversion position and the period can be manipulated. In addition, it is found that the tight focusing of the Airy pulse is also controllable.

Physics-based deep learning for modeling nonlinear pulse propagation in optical fibers

A physics-based deep learning (DL) method termed Phynet is proposed for modeling the nonlinear pulse propagation in optical fibers totally independent of the ground truth. The presented Phynet is a combination of a handcrafted neural network and the nonlinear Schrödinger physics model. In particular, Phynet is optimized through physics loss generated by the interaction between the network and the physical model rather than the supervised loss. The inverse pulse propagation problem is leveraged to exemplify the performance of Phynet when in comparison to the typical DL method under the same structure and datasets. The results demonstrate that Phynet is able to precisely restore the initial pulse profiles with varied initial widths and powers, while revealing a similar prediction accuracy compared with the typical DL method. The proposed Phynet method can be expected to break the severe bottleneck of the traditional DL method in terms of relying on abundant labeled data during the training phase, which thus brings new insight for modeling and predicting the nonlinear dynamics of the fibers.

Graded-index breathing solitons from Airy pulses in multimode fibers

Breathing solitons, as localized wave packets with a periodic evolution in amplitude and duration, are able to model extreme wave events in complex nonlinear dispersive systems. We have numerically studied the formation and manipulation of graded-index breathing solitons embedded in nonlinear multimode fibers based on a single nonlinear Schrödinger equation that includes the spatial self-imaging effect through a periodically varying nonlinear parameter. Through changing specific parameters of the input optical field, we can manipulate the period and depth of graded-index breathing soliton dynamics under different relative strengths between the dispersion length and the self-imaging period of the multimode fiber. Our study can explicitly derive a robust mechanism to control the behavior of the breathing localized structure directly and contribute to a better understanding of the much more complex nonlinear graded-index soliton dynamics in multimode fibers.