PT-symmetry in nonlinear twisted multi-core fibers

TL;DR

This paper investigates how nonlinear twisted multi-core fibers with PT symmetry can have their energy transport and symmetry breaking thresholds controlled by twisting rate, gain/losses, and nonlinearity, revealing non-monotonic behaviors.

Contribution

It introduces a novel analysis of PT-symmetric nonlinear fibers showing how twisting rate influences symmetry breaking thresholds in complex ways.

Findings

Threshold of PT-symmetry breaking varies non-monotonically with twisting rate.

Twisting can nearly eliminate or significantly increase the symmetry breaking threshold.

Nonlinearity generally reduces the symmetry breaking threshold in these fibers.

Abstract

We address propagation of light in nonlinear twisted multi-core fibers with alternating amplifying and absorbing cores that are arranged into the PT - symmetric structure. In this structure, the coupling strength between neighboring cores and global energy transport can be controlled not only by the nonlinearity strength, but also by gain and losses and by the fiber twisting rate. The threshold level of gain/losses, at which PT -symmetry breaking occurs, is a non-monotonic function of the fiber twisting rate and it can be reduced nearly to zero or, instead, notably increased just by changing this rate. Nonlinearity usually leads to the monotonic reduction of the symmetry breaking threshold in such fibers.