Apparent non-conservation of momentum of light due to strongly coupled nonlinear dynamics in a multimode optical fiber

TL;DR

This paper explores a nonlinear optical phenomenon in multimode fibers where apparent momentum non-conservation occurs due to strong mode interactions, revealing it as a natural effect with potential applications in quantum light generation.

Contribution

It introduces a new regime of strong nonlinear interaction in multimode fibers and clarifies that the apparent momentum violation is a natural consequence of mode coupling.

Findings

Demonstrates saturable spatial mode conversion in multimode fibers.

Shows that apparent momentum non-conservation is a result of nonlinear dynamics.

Suggests applications in generating exotic quantum states of light.

Abstract

The intimate interaction between phase-matched parametric amplification and strong nonlinear mode coupling in a multimode optical fiber results in a saturable spatial mode conversion that appears to violate the conservation of momentum. We investigate, by theory and experiment, this new regime of strong nonlinear interaction in multimode optical fibers and show that the appearance of the non-conservation of linear momentum is merely a clever sleight of hand by nature. This novel saturable mode conversion can potentially be used in a variety of applications including the generation of exotic quantum states of light.