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Thulium fiber lasers with longitudinally modified concentration

Thulium fiber lasers with longitudinally modified concentration
Thulium fiber lasers with longitudinally modified concentration

High-power fiber lasers generate local heat load extremes during their operation, which increase the fiber temperature and lead to adverse thermal effects, such as transverse mode instability or cladding/coating thermal damage. The local temperature extremes are usually located near the end of a fiber where the pump power is delivered. In this paper, longitudinally inhomogeneous doping concentration profiles are applied to reduce the heat load extremes. Utilizing a new degree of freedom, it is shown by both simulations and measurements that maximal temperature along the fiber can be effectively decreased by using active fibers with an increasing concentration profile in the direction of pumping power. The concept is studied by a comprehensive numerical model that considers temperature-dependent parameters and is also demonstrated by measurement on an in-house built thulium-doped fiber laser formed by spliced sections with different concentrations. The output power of 54 W with the slope efficiency exceeding 62 % was reached.

concentration profile, fiber laser, heat load, temperature, thulium
2095-4719
Švejkarová, Bára
7e8ef127-f5c7-40b9-bf37-5ace5c5382c6
Grábner, Martin
369668e1-94cb-46c7-905e-1c0319bbfec3
Aubrecht, Jan
d03efa7e-a85c-4eb0-a23f-7c5a39127dec
Švejkar, Richard
e22194cd-6046-4f2f-b644-af922bec55c8
Pokorný, Jan
013a8aba-a213-4299-9b2d-05e615ce6c5a
Kamrádek, Michal
27dd3eda-3d93-4237-a637-8e8e3f1b9416
Podrazký, Ondřej
ea2818cf-8852-4c0e-8aff-195b613c778b
Kašík, Ivan
62ae9530-a54d-4685-a2c4-44f49ec558fc
Honzátko, Pavel
94fb59ad-b8c5-4f2e-9e05-8eb9e1ba3675
Clarkson, Andrew
3b060f63-a303-4fa5-ad50-95f166df1ba2
Peterka, Pavel
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Švejkarová, Bára
7e8ef127-f5c7-40b9-bf37-5ace5c5382c6
Grábner, Martin
369668e1-94cb-46c7-905e-1c0319bbfec3
Aubrecht, Jan
d03efa7e-a85c-4eb0-a23f-7c5a39127dec
Švejkar, Richard
e22194cd-6046-4f2f-b644-af922bec55c8
Pokorný, Jan
013a8aba-a213-4299-9b2d-05e615ce6c5a
Kamrádek, Michal
27dd3eda-3d93-4237-a637-8e8e3f1b9416
Podrazký, Ondřej
ea2818cf-8852-4c0e-8aff-195b613c778b
Kašík, Ivan
62ae9530-a54d-4685-a2c4-44f49ec558fc
Honzátko, Pavel
94fb59ad-b8c5-4f2e-9e05-8eb9e1ba3675
Clarkson, Andrew
3b060f63-a303-4fa5-ad50-95f166df1ba2
Peterka, Pavel
6b5f168e-984a-4d6d-825d-458210fb2ed8

Švejkarová, Bára, Grábner, Martin, Aubrecht, Jan, Švejkar, Richard, Pokorný, Jan, Kamrádek, Michal, Podrazký, Ondřej, Kašík, Ivan, Honzátko, Pavel, Clarkson, Andrew and Peterka, Pavel (2025) Thulium fiber lasers with longitudinally modified concentration. High Power Laser Science and Engineering. (doi:10.1017/hpl.2025.10051).

Record type: Article

Abstract

High-power fiber lasers generate local heat load extremes during their operation, which increase the fiber temperature and lead to adverse thermal effects, such as transverse mode instability or cladding/coating thermal damage. The local temperature extremes are usually located near the end of a fiber where the pump power is delivered. In this paper, longitudinally inhomogeneous doping concentration profiles are applied to reduce the heat load extremes. Utilizing a new degree of freedom, it is shown by both simulations and measurements that maximal temperature along the fiber can be effectively decreased by using active fibers with an increasing concentration profile in the direction of pumping power. The concept is studied by a comprehensive numerical model that considers temperature-dependent parameters and is also demonstrated by measurement on an in-house built thulium-doped fiber laser formed by spliced sections with different concentrations. The output power of 54 W with the slope efficiency exceeding 62 % was reached.

Text
thulium-fiber-lasers-with-longitudinally-modified-concentration - Accepted Manuscript
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More information

e-pub ahead of print date: 18 July 2025
Keywords: concentration profile, fiber laser, heat load, temperature, thulium

Identifiers

Local EPrints ID: 505495
URI: http://eprints.soton.ac.uk/id/eprint/505495
ISSN: 2095-4719
PURE UUID: 9b5a80a8-c582-423f-b764-7345fdb3c88d
ORCID for Richard Švejkar: ORCID iD orcid.org/0000-0002-2421-2177

Catalogue record

Date deposited: 10 Oct 2025 16:34
Last modified: 11 Oct 2025 02:18

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Contributors

Author: Bára Švejkarová
Author: Martin Grábner
Author: Jan Aubrecht
Author: Richard Švejkar ORCID iD
Author: Jan Pokorný
Author: Michal Kamrádek
Author: Ondřej Podrazký
Author: Ivan Kašík
Author: Pavel Honzátko
Author: Andrew Clarkson
Author: Pavel Peterka

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