TY - JOUR

T1 - Real-time mode dynamics of Stokes beam in multimode Raman fiber laser with mode-selective mirror

AU - Gervaziev, M D

AU - Kuznetsov, A G

AU - Revyakin, A A

AU - Simonov, V A

AU - Достовалов, Александр Владимирович

AU - Терентьев, Вадим Станиславович

AU - Бабин, Сергей Алексеевич

AU - Харенко, Денис Сергеевич

N1 - This work was funded by Russian Science Foundation (21-72-30024).

PY - 2025

Y1 - 2025

N2 - Raman fiber lasers (RFL) based on multimode (MM) fibers are promising in terms of potential increase in power while maintaining high beam quality. One fundamental challenge on this way is the so-called mode instability (MI). In this paper we perform a real-time mode decomposition of the MM RFL with the dielectric thin-film mirror at the cavity output for MI investigation. The typical time of mode dynamics measured to be at the level of hundreds of ms and depends on the power and diameter of the output mirror. The decomposition results allow us to conclude that the 12μm mirror is optimal in terms of the fundamental mode power fraction (∼50%). At the same time, a significant contribution of the next radially symmetric mode (∼20%) is found. With increasing power, the amplitude of oscillations of the mode composition decreases (near the Raman threshold it is 40%, at high power — 10%). We also demonstrate real-time mode decomposition of 10 modes simultaneously.

AB - Raman fiber lasers (RFL) based on multimode (MM) fibers are promising in terms of potential increase in power while maintaining high beam quality. One fundamental challenge on this way is the so-called mode instability (MI). In this paper we perform a real-time mode decomposition of the MM RFL with the dielectric thin-film mirror at the cavity output for MI investigation. The typical time of mode dynamics measured to be at the level of hundreds of ms and depends on the power and diameter of the output mirror. The decomposition results allow us to conclude that the 12μm mirror is optimal in terms of the fundamental mode power fraction (∼50%). At the same time, a significant contribution of the next radially symmetric mode (∼20%) is found. With increasing power, the amplitude of oscillations of the mode composition decreases (near the Raman threshold it is 40%, at high power — 10%). We also demonstrate real-time mode decomposition of 10 modes simultaneously.

KW - Mode decomposition

KW - Mode instabilities

KW - Multimode fiber

KW - Nonlinear fiber optics

KW - Raman fiber laser

UR - https://doi.org/10.1016/j.optlastec.2025.112512

UR - https://www.mendeley.com/catalogue/d8c8bb79-5943-3c56-9bbc-d8eb725e0045/

UR - https://www.scopus.com/record/display.uri?eid=2-s2.0-85216536342&origin=inward&txGid=3f6b9a7bed805a36166a7dd6c63e15ad

U2 - 10.1016/j.optlastec.2025.112512

DO - 10.1016/j.optlastec.2025.112512

M3 - Article

VL - 184

JO - Optics and Laser Technology

JF - Optics and Laser Technology

SN - 0030-3992

IS - January

M1 - 112512

ER -