Scalar - vector soliton fiber lasers

TL;DR

This paper reports a fiber laser that generates vector solitons in a birefringent segment and scalar solitons after a polarizer, revealing new solutions in polarization-dependent nonlinear systems.

Contribution

It introduces a fiber laser system where vector and scalar solitons coexist and transform, expanding understanding of polarization effects in nonlinear fiber lasers.

Findings

Vector solitons form in birefringent segments.

Scalar solitons occur after the polarizer.

The system bridges vector and scalar soliton regimes.

Abstract

Rapid progress in passively mode-locked fiber lasers is currently driven by the recent discovery of vector feature of mode-locking pulses, namely, the group velocity-locked vector solitons, the phase locked vector solitons, and the high-order vector solitons. Those vector solitons are fundamentally different from the previously known scalar solitons. Here, we report a fiber laser where the mode-locked pulse evolves as a vector soliton in the strong birefringent segment and is transformed into a regular scalar soliton after the polarizer within the laser cavity. The existence of solutions in a polarization-dependent cavity comprising a periodic combination of two distinct nonlinear waves is novel and likely to be applicable to various other nonlinear systems. For very large local birefringence, our laser approaches the working regime of vector soliton lasers, while it approaches scalar soliton fiber lasers under the conditions of very small birefringence.