Nonlinear Waves and Turbulence in Photonics 2022 - Abstract

Staliunas, Kestutis

Non-Hermitian mode cleaning in periodically modulated multimode fibers

We show that simultaneous periodic modulation of the propagation constant and of gain/loss coefficient along the multimode fibers results in unidirectional coupling among the transverse modes, which, depending on the modulation parameters, leads to the enhancement or reduction of the excitation of higher order transverse modes. In the latter case the mode-cleaning is predicted, in ideal case resulting in single-mode spatially coherent output. We prove the effect by numerically solving the modulated wave propagation equation both in linear, and Kerr-nonlinear case, as well on semi-analytically on simplified gaussian beam models. The proposed non-Hermitian mode cleaning [1] is related to recently proposed generic principle of turbulence control by non-Hermitian periodic in space and time potentials [2].


[1] N. Akhter, M. Botey, R. Herrero, and K. Staliunas, Non-Hermitian Mode Cleaning in Periodically Modulated Multimode Fibers, PRL submitted, 2022;

[2] S.B. Ivars, M. Botey, R. Herrero, and K. Staliunas, Optical Turbulence control by non-Hermitian potentials, Phys. Rev. A 105, 033510 (2022).