Floquet Spin-Glass Phase in a Random Fiber Laser

Abstract

In this chapter, the authors discuss the example of a remarkable new photonic phase that has been very recently reported in a strongly disordered erbium-based Random Fiber Laser (RFL), the so-called Floquet spin-glass phase. Differently from the photonic equilibrium spin-glass phase reported in several random lasers and RFLs, the Floquet glassy behavior in the erbium-based RFL is clearly a non-equilibrium one. In the strongly nonlinear disordered regime a photonic Floquet spin-glass phase is clearly evidenced from the dynamics of the Parisi overlap parameter and asymmetry properties of the spin-glass order parameter distribution function. The quenched disorder responsible for the spatial eigenmode localization was provided by a remarkable amount of specially designed random Bragg gratings inscribed in the fiber core and correlations among a quite extensive number of output spectra were analyzed. The Parisi overlap parameter and asymmetry properties of the spin-glass order parameter distribution function in the dynamical photonic Floquet phase were nicely described by theoretical arguments.