TY - GEN

T1 - Mode decomposition of Kerr self-cleaned beams by phase only SLM

AU - Kharenko, Denis S.

AU - Gervaziev, Mikhail D.

AU - Zhdanov, Innokentiy

AU - Podivilov, Evgeniy V.

AU - Babin, Sergey A.

AU - Wabnitz, Stefan

N1 - Funding Information: This work was supported by the Russian Ministry of Science and Education (Grant No. 14.Y26.31.0017). M.G. was also supported by RFBR (Grant No. 20-32-90132), S.B. and D.Kh were supported by RSF (Grant No. 21-42-00019). S.W. was also supported by the European Research Council (Grant. No. 740355 and No. 874596). Publisher Copyright: © 2021 SPIE. Copyright: Copyright 2021 Elsevier B.V., All rights reserved.

PY - 2021

Y1 - 2021

N2 - Graded-index multimode optical fibers have recently attracted a renewed attention, thanks to the discovery of new nonlinear effects, such as Kerr beam self-cleaning. In essence, Kerr self-cleaning involves a flow of the propagating beam energy into the fundamental mode of the fiber, accompanied by a redistribution of the remaining energy among high-order modes. Increasing the fundamental mode energy leads to a significant improvement of the output beam quality. A standard method to determine beam quality is to measure the M2 parameter. However, since self-cleaning involves the nonlinear redistribution of energy among a large number of fiber modes, measuring a single beam quality parameter is not sufficient to characterize the effect. A properly informative approach requires performing the mode decomposition of the output beam. Mode decomposition permits to evaluate the energy distribution among all of the excited fiber modes, which enables investigations of nonlinear mode coupling processes at a qualitatively new level. In this work, we demonstrate an efficiency mode decomposition method based on holography, which is suitable for analyzing the self-cleaning effect. In a theoretical study, we describe the solution of the mode decomposition problem for the modes of the graded-index multimode fiber. In an experimental investigation, we demonstrate the decomposition of both low-power (speckled) and self-cleaned beams, involving more than 80 modes.

AB - Graded-index multimode optical fibers have recently attracted a renewed attention, thanks to the discovery of new nonlinear effects, such as Kerr beam self-cleaning. In essence, Kerr self-cleaning involves a flow of the propagating beam energy into the fundamental mode of the fiber, accompanied by a redistribution of the remaining energy among high-order modes. Increasing the fundamental mode energy leads to a significant improvement of the output beam quality. A standard method to determine beam quality is to measure the M2 parameter. However, since self-cleaning involves the nonlinear redistribution of energy among a large number of fiber modes, measuring a single beam quality parameter is not sufficient to characterize the effect. A properly informative approach requires performing the mode decomposition of the output beam. Mode decomposition permits to evaluate the energy distribution among all of the excited fiber modes, which enables investigations of nonlinear mode coupling processes at a qualitatively new level. In this work, we demonstrate an efficiency mode decomposition method based on holography, which is suitable for analyzing the self-cleaning effect. In a theoretical study, we describe the solution of the mode decomposition problem for the modes of the graded-index multimode fiber. In an experimental investigation, we demonstrate the decomposition of both low-power (speckled) and self-cleaned beams, involving more than 80 modes.

KW - Beam characterization

KW - GRIN multi-mode fibers

KW - Mode decomposition

KW - Spatial light modulation

UR - http://www.scopus.com/inward/record.url?scp=85107200590&partnerID=8YFLogxK

U2 - 10.1117/12.2578240

DO - 10.1117/12.2578240

M3 - Conference contribution

AN - SCOPUS:85107200590

T3 - Proceedings of SPIE - The International Society for Optical Engineering

BT - Real-time Measurements, Rogue Phenomena, and Single-Shot Applications VI

A2 - Solli, Daniel R.

A2 - Herink, Georg

A2 - Bielawski, Serge

PB - SPIE

T2 - Real-time Measurements, Rogue Phenomena, and Single-Shot Applications VI 2021

Y2 - 6 March 2021 through 11 March 2021

ER -