Space-time excitation creates soliton trains in multimode fibers

TL;DR

This paper demonstrates that space-time excitation of multimode fibers can generate trains of multimode solitons with properties dictated by initial pulse characteristics, revealing new nonlinear dynamics.

Contribution

It introduces a method to generate multimode soliton trains in fibers using space-time coupled pulses, linking soliton properties to initial pulse topology and power.

Findings

Space-time coupling excites distinct spatial modes with different temporal profiles.

Proper input power causes these profiles to split into multiple multimode solitons.

The number and properties of solitons depend on the initial pulse's topological charge.

Abstract

In this work, we show that injecting a single space-time-coupled light pulse-beam into a multimode graded-index fiber generates a train of multimode solitons. Space-time couplings excite the spatial modes with distinct temporal profiles. Due to nonlinear interactions, with a properly chosen input power these profiles split into several unique multimode solitons. In the case of a spatially chirped input pulse, two solitons composed of modes $LP_{01}$ and $LP_{11}$ are formed. In the case of the injection of a space-time optical vortex, characterized by its topological charge $\ell$, a train composed of $|\ell| + 1$ multimode solitons is generated. Their energy and modal composition are directly determined by the absolute value of the topological charge.