Fiber Bragg gratings in active multimode XLMA fibers for high-power kW-class fiber lasers

S. Klein; M. Giesberts; P. Baer; M. Raguse; O. Fitzau; M. Traub; H.-D. Hoffmann; V. Krause; G. Rehmann

doi:10.1117/12.2545738

21 February 2020 Fiber Bragg gratings in active multimode XLMA fibers for high-power kW-class fiber lasers

S. Klein, M. Giesberts, P. Baer, M. Raguse, O. Fitzau, M. Traub, H.-D. Hoffmann, V. Krause, G. Rehmann

Proceedings Volume 11260, Fiber Lasers XVII: Technology and Systems; 1126025 (2020) https://doi.org/10.1117/12.2545738
Event: SPIE LASE, 2020, San Francisco, California, United States

Abstract

Within the EKOLAS consortium, which is part of the BMBF-funded EffiLAS (Efficient high-performance laser beam sources) research initiative, we are developing fiber Bragg gratings (FBG) directly written into multimode fibers. Fiber lasers are an established beam source for high-power materials processing due to their high efficiency and high average output power at high beam quality. By using FBG as fiber-integrated output mirrors, which is state-of-the-art in singlemode fiber lasers, we aim to reduce the complexity and increase robustness and reliability of multimode fiber resonators. Therefore, we are investigating the use of FBG as outcoupling mirrors in multimode high-power multimode fiber lasers. As a first step, we directly write an FBG into an active extra-large mode area (XLMA) fiber with <100 μm core and use the FBG as low reflective outcoupling mirror for the fiber resonator with simultaneous frequency stabilization. The setup delivers an output power of more than 800 W at 1077 nm. The output power of the system was limited by the pump laser setup and not by the FBG or its temperature. The FBG is passively cooled and the measured temperature of the fiber at the grating is below 130 °C at 800 W output power. As the next step, we set up an active XLMA-fiber (core <100 μm) with an FBG as outcoupling mirror into a laser resonator with water cooling of the resonator fiber and optimized pump coupling. This setup delivers an output power of more than 8 kW at 1077 nm without failure of the FBG.

Citation Download Citation

S. Klein, M. Giesberts, P. Baer, M. Raguse, O. Fitzau, M. Traub, H.-D. Hoffmann, V. Krause, and G. Rehmann "Fiber Bragg gratings in active multimode XLMA fibers for high-power kW-class fiber lasers", Proc. SPIE 11260, Fiber Lasers XVII: Technology and Systems, 1126025 (21 February 2020); https://doi.org/10.1117/12.2545738

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available

Members: $17.00

Non-members: $21.00 ADD TO CART

PROCEEDINGS
10 PAGES

DOWNLOAD PAPER SAVE TO MY LIBRARY

GET CITATION

RIGHTS & PERMISSIONS

Get copyright permission Get copyright permission on Copyright Marketplace

KEYWORDS

Fiber Bragg gratings

Fiber lasers

Multimode fibers

Resonators

Mirrors

Temperature metrology

Reflectivity

Show All Keywords

Keywords/Phrases

Search In:

Publication Years