Singlemode spatiotemporal soliton attractor in multimode GRIN fibers

TL;DR

This study demonstrates that multimode femtosecond solitons in parabolic GRIN fibers naturally evolve into a singlemode soliton, with the fundamental mode acting as a dynamical attractor over record propagation distances.

Contribution

It provides experimental and numerical evidence of the singlemode attractor phenomenon in multimode fibers, challenging previous variational approach assumptions.

Findings

Multimode solitons irreversibly evolve into singlemode solitons.

The fundamental mode acts as a dynamical attractor.

Propagation distances up to 5600 chromatic dispersion lengths observed.

Abstract

Experimental and numerical studies of spatiotemporal femtosecond soliton propagation over up to 1 km spans of parabolic graded-index (GRIN) fibers reveal that initial multimode soliton pulses naturally and irreversibly evolve into a singlemode soliton. This is carried by the fundamental mode of the fiber, which acts as a dynamical attractor of the multimode system for up to the record value (for multimode fibers) of 5600 chromatic dispersion distances. This experimental evidence invalidates the use of variational approaches, which intrinsically require that the initial multimode propagation of a self-imaging soliton is indefinitely maintained.