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PT-symmetry breaking in dual-core phosphate-glass photonic crystal fibers

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Version 2 2023-09-29, 08:19
Version 1 2023-09-28, 09:36
preprint
posted on 2023-09-29, 08:19 authored by Mattia Longobucco, The Tai Le Xuan, Viet Hung Nguyen, Jarosław Cimek, Bartosz Paluba, Ryszard Buczynski, Marek Trippenbach
We investigate the properties of a soft glass dual-core photonic crystal fiber for application in multicore waveguiding with balanced gain and loss. Its base material is a phosphate glass in a P2O5-Al2O3-Yb3O3-BaO-ZnO-MgO-Na2O oxide system. The separated gain and loss channels are realized with two cores with ytterbium and copper doping of the base phosphate glass. The ytterbium-doped core supports a laser (gain) activity under excitation with a pump at 1000 nm wavelength, while the copper-doped is responsible for strong attenuation at the same wavelength. We establish conditions for an exact balance between gain and loss and investigate pulse propagation by solving a system of coupled generalized nonlinear Schrödinger equations. We predict two states of light under excitation with hyperbolic secant pulses centered at 1000 nm: 1) linear oscillation of the pulse energy between gain and loss channel (PT-symmetry state), with strong power attenuation; 2) retention of the pulse in the excited gain channel (broken PT-symmetry), with very modest attenuation. The optimal pulse energy levels were identified to be 100 pJ (first state) and 430 pJ (second state).

History

Funder Name

Narodowe Centrum Nauki (2019/33/N/ST7/03142, PRELUDIUM-17); National Foundation for Science and Technology Development (103.01-2021.152)

Preprint ID

109337