Topological solitons as addressable phase bits in a driven laser

TL;DR

This paper demonstrates the experimental creation and control of phase-based topological solitons in a laser, revealing their potential as robust information carriers for advanced optical communication.

Contribution

It provides the first experimental and analytical evidence of phase solitons in laser systems, highlighting their topological nature and potential for information encoding.

Findings

Phase bits can be nucleated and canceled individually.

Phase solitons exhibit topological stability.

Analogy with Sine-Gordon solitons confirmed.

Abstract

Optical localized states are usually defined as self-localized bistable packets of light which exist as independently controllable optical intensity pulses either in the longitudinal or transverse dimension of nonlinear optical systems. Here we provide the first experimental and analytical demonstration of the existence of longitudinal localized states which exist fundamentally in the phase of laser light. These robust and versatile phase bits can be individually nucleated and canceled in an injection-locked semiconductor laser operated in a neuron- like excitable regime and submitted to delayed feedback. The demonstration of their control opens the way to their use as phase information units in next generation coherent communication systems. We analyze our observations in terms of a generic model which confirms the topological nature of the phase bits and discloses their formal but profound analogy with Sine-Gordon solitons.