TY - GEN

T1 - Beam cleaning effect in multimode fiber tapered amplifier with CW single-frequency seed

AU - Kuznetsov, A. G.

AU - Skvortsov, M. I.

AU - Vlasov, A. A.

AU - Gervaziev, Mikhail

AU - Revyakin, A. A.

AU - Kharenko, D. S.

AU - Wabnitz, S.

AU - Babin, Sergey A. A.

N1 - A. G. Kuznetsov, M. I. Skvortsov, A. A. Vlasov, M. D. Gervaziev, A. A. Revyakin, D. S. Kharenko, S. Wabnitz, and S. A. Babin "Beam cleaning effect in multimode fiber tapered amplifier with CW single-frequency seed", Proc. SPIE 13711, Advanced Lasers, High-Power Lasers, and Applications XVI, 137110Z (19 November 2025); https://doi.org/10.1117/12.3077184 The study is supported by Russian Science Foundation (№ 21-72-30024-П).

PY - 2025/11/19

Y1 - 2025/11/19

N2 - Multimode optical fibers have attracted a lot of interest over the past decade due to their great potential for fiber lasers with enhanced power, as well as new nonlinear optical phenomena manifesting with the use of high-energy pulsed multimode beams. One of these phenomena, spatial self-cleaning is a most intriguing nonlinear effect involving the transformation of a speckled beam into a smooth beam with a bell-shaped profile at the multimode fiber output which is observed above some threshold value of peak power for sub-nanosecond pulses. The effect is usually observed in passive multimode fibers with graded-index (GRIN) profile, but other types of fibers may exhibit similar behavior. For example, in active (Yb-doped) multimode GRIN fiber taper a highly-multimode pulsed output beam observed at low power experiences self-cleaning after amplification to peak power of ~20 kW with quality parameter M2 improved from >10 to ~4. Here we study amplification of a continuous-wave (CW) single-frequency (SF) radiation in similar multimode GRIN fiber taper and demonstrate beam cleaning effect at much lower output power with beam quality improvement to near- Gaussian diffraction-limited beam (M2

AB - Multimode optical fibers have attracted a lot of interest over the past decade due to their great potential for fiber lasers with enhanced power, as well as new nonlinear optical phenomena manifesting with the use of high-energy pulsed multimode beams. One of these phenomena, spatial self-cleaning is a most intriguing nonlinear effect involving the transformation of a speckled beam into a smooth beam with a bell-shaped profile at the multimode fiber output which is observed above some threshold value of peak power for sub-nanosecond pulses. The effect is usually observed in passive multimode fibers with graded-index (GRIN) profile, but other types of fibers may exhibit similar behavior. For example, in active (Yb-doped) multimode GRIN fiber taper a highly-multimode pulsed output beam observed at low power experiences self-cleaning after amplification to peak power of ~20 kW with quality parameter M2 improved from >10 to ~4. Here we study amplification of a continuous-wave (CW) single-frequency (SF) radiation in similar multimode GRIN fiber taper and demonstrate beam cleaning effect at much lower output power with beam quality improvement to near- Gaussian diffraction-limited beam (M2

KW - fiber laser

KW - DFB laser

KW - single-frequency

KW - multimode fiber

KW - tapered fiber amplifier

KW - beam quality

KW - beam selfcleaning

KW - transverse modes

UR - https://www.scopus.com/pages/publications/105024759078

UR - https://www.mendeley.com/catalogue/4d305c4e-1ddf-36c1-9306-38c6e6431095/

U2 - 10.1117/12.3077184

DO - 10.1117/12.3077184

M3 - Conference contribution

VL - 13711

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

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

A2 - Jiang, Shibin

A2 - Li, Zhaoyang

A2 - Hartl, Ingmar

PB - The International Society for Optical Engineering

T2 - SPIE/COS Photonics Asia 2025

Y2 - 12 October 2025 through 14 October 2025

ER -