TY - GEN

T1 - Mechanism of brightness enhancement in multimode LD-pumped graded-index fiber Raman lasers

AU - Babin, Sergey A.

AU - Kuznetsov, Alexey G.

AU - Sidelnikov, Oleg S.

AU - Kablukov, Sergey I.

AU - Podivilov, Evgeny V.

AU - Fedoruk, Mikhail P.

AU - Wabnitz, Stefan

N1 - Funding Information: Simulated and experimental beam profiles are compared in Fig.1(a,b) in absolute intensity units (W per square micron) within the GRIN fiber core of 100 μm diameter: here we can see the input pump beam (blue), the attenuated pump beam without depletion (dashed), the depleted output pump beam (black), and the generated Stokes beam (red). The comparison between experiments and simulations shows a very good agreement, both in the amplitude and in the shapes of the beams. Our simulations have revealed that random mode coupling in GRIN fibers leads to a parabolic pump beam shape, with a broadening of the hole burnt due to the pump depletion. Moreover, random coupling also greatly broadens and reduces the intensity of the Stokes beam, whereas Kerr self-cleaning and spatial filtering effects enhance both the intensity and beam quality of the Stokes wave so that a high brightness enhancement factor at pump-to-Stokes conversion is obtained. At the same time, the depleted pump beam profiles remain always nearly insensitive to the different physical effects. A more detailed comparison between theory and experiments, confirming these conclusions, will be presented at the conference. The study is supported by the Russian Science Foundation (21-42-00019) and the Ministry of Science and Higher Education of the Russian Federation (14.Y26.31.0017). Publisher Copyright: © 2021 The Author (s)

PY - 2021

Y1 - 2021

N2 - A theory describing experimental beam profiles of multimode fiber Raman lasers is developed: random mode coupling, Kerr self-cleaning and spatial filtering play a decisive role in shaping Stokes beams, whereas depleted pump beams remain insensitive.

AB - A theory describing experimental beam profiles of multimode fiber Raman lasers is developed: random mode coupling, Kerr self-cleaning and spatial filtering play a decisive role in shaping Stokes beams, whereas depleted pump beams remain insensitive.

UR - http://www.scopus.com/inward/record.url?scp=85130238168&partnerID=8YFLogxK

M3 - Conference contribution

AN - SCOPUS:85130238168

T3 - Optics InfoBase Conference Papers

BT - Laser Applications Conference, LAC 2021

PB - Optica Publishing Group (formerly OSA)

T2 - Laser Applications Conference, LAC 2021 - Part of Laser Congress 2021

Y2 - 3 October 2022 through 7 October 2022

ER -