Fiber Lasers

Fraunhofer ILT develops fiber lasers and amplifiers with adapted properties for pulsed and CW operation. The focus is on controlling special properties - for example, wavelength, spectral bandwidth, polarization, or beam quality. To address different applications, fiber lasers based on ytterbium-, thulium-, holmium- as well as neodymium-doped fibers are being developed, which enable the use of wavelengths in the ranges of 900-1100 nm, as well as 1900-2100 nm. Furthermore, pulse duration ranges from a few 10 picoseconds to milliseconds can be generated by using different concepts for pulse generation, from gain switching to mode coupling. Commercial and in-house developed tools can be used to simulate oscillators and linear amplifiers with spectral, temporal and modal resolution.

Current research topics include ultra-high stable fiber amplifiers, high output power CW fiber lasers, and pulsed fiber lasers, in QCW, Q-switched, or mode-locked configurations. Furthermore, fiber-based components, such as multimode fiber Bragg gratings, are being developed. The used packaging and interconnection technology enables laser systems with low attenuation and high power stability. The high degree of integration results in robust and alignment-free beam sources. For example, systems based on active fibers with large cores in the range of 50 µm to 100 µm for pulsed operation with pulse durations of a few 10 nanoseconds as well as narrowband amplifiers for CW operation with line widths of less than 10 kHz have been realized.

Fraunhofer ILT offers its customers feasibility studies for individual tasks, the development of fiber lasers with adapted radiation properties, the integration, further development or simulation of fiber laser systems as well as consulting services for design.

High Power CW Lasers with Fundamental Mode Beam Quality

• Free space resonators
• Fiber-Bragg gratings
• All-fiber lasers
• Polarized lasers
• Fiber laser resonators and amplifiers
• Design and simulation

Pulsed Fiber Lasers and Amplifiers

• Fiber amplifiers for pulsed laser diodes
• Single- and multi-stage amplifiers
• Gain-switched fiber lasers
• PD from ps to µs
• PRF from kHz to MHz

Efficient, High Brilliant Pumping Technology

• Concentrated and allocated pumping
• Multimode fused combiners
• Single emitters, multi-single emitters, multi emitters

Fiber Preparation and Assembly, Fiber Laser Components

• Cleaving, splicing, recoating
• Fiber tapers
• Mode strippers
• Isolators
• Detailed simulation 3D laser structuring for preforms and components

Cebeci, P., Giesberts, M., Baer, P., Hoffmann, H.:
Narrow-linewidth single-stage fiber amplifier with an output power of 15 W at 1064 nm.
SPIE LASE 2024, United States, 27 Jan- 1 Feb 2024, San Francisco, California.
Proceedings Volume 12865, Fiber Lasers XXI: Technology and Systems; 128651L (2024)
https://doi.org/10.1117/12.3003178

Giesberts, M., Bontke, F., Reiter, M., Baer, P., Hoffmann, H., Bartram, M.:
Thulium-doped high-power fiber amplifier for <500 ps directly gain-switched seed diodes.
SPIE LASE 2024, 27 Jan. - 01 FEb. 2024. San Francisco, US.
Proceedings Volume 12865, Fiber Lasers XXI: Technology and Systems; 128651I (2024)
https://doi.org/10.1117/12.3002692

Baer, P., Cebeci, P., Reiter, M., Giesberts, M., Hoffmann, D.:
10 W-class, narrow-linewidth, linearly polarized, low-noise Holmium-doped Fiber Amplifier at 2095 nm.
Optics Continuum 3(8), 1302-1310 (2024)
https://doi.org/10.1364/OPTCON.525036 (Open Access)

Baer, P.:
Erhöhung der durch nichtlineare Effekte verursachten Leistungsgrenzen von Faserlasern durch besondere Fasergeometrien
Apprimus Verlag (2024)
https://doi.org/10.18154/RWTH-2024-03643

Baer, P., Cebeci, P., Reiter, M., Giesberts, M., Hoffmann, H.-D.:
Narrow-linewidth and low-noise holmium-doped fiber amplifier at 2095 nm with compact packaging
SPIE LASE, 2024, San Francisco, California, United States. Proceedings Volume 12865, Fiber Lasers XXI: Technology and Systems; 128651J (2024)
https://doi.org/10.1117/12.3002827

Baer, P., Cebeci, P., Reiter, M., Bontke, F., Giesberts, M., Hoffmann, D.:
Ultra-low-noise, single-frequency, all-PM Thulium- and Holmium-doped Fiber Amplifiers at 1950 nm and 2090 nm for third-generation Gravitational Wave Detectors.
IEEE Photonics Journal 16(1), 1500809, (2024)
https://doi.org/10.1109/JPHOT.2024.3354454 (Open Access)

Cebeci, P., Giesberts, M., Baer, P., Hoffmann, H.-D.:
Narrow-linewidth single-stage fiber amplifier with an output power of 15 W at 1064 nm
SPIE LASE, 2024, San Francisco, California, United States. Proceedings Volume 12865, Fiber Lasers XXI: Technology and Systems; 128651J (2024)
https://doi.org/10.1117/12.3003178

Giesberts, M., Bontke, F., Reiter, M., Baer, P., Hoffmann, H.-D., Bartram, M.:
Thulium-doped high-power fiber amplifier for ⪅500 ps directly gain-switched seed diodes
SPIE LASE, 2024, San Francisco, California, United States. Proceedings Volume 12865, Fiber Lasers XXI: Technology and Systems; 128651J (2024)
https://doi.org/10.1117/12.3002692

Reiter, M., Baer, P.:
Thermo-optical Simulation of Holmium-doped Fiber Amplifiers for high-power Applications.
Optics Continuum 3(8), 1516-1527, (2024)
https://doi.org/10.1364/OPTCON.532149

Dahl, K., Baatzsch, A., Baron, F., Betz, P., Dahl, C., Dittmar, S., Herding, M., Krieger, J., Liebherr, T., Schäfer, H., Schäfer, L., Serenok, P., Kownatzki, J., Schillinger, H., Cebeci, P., Fitzau, O., Giesberts, M., Gohlke, M., Sanjuan, J.:
International Conference on Space Optics — ICSO 2022, 3-7 October 2022, Dubrovnik, Croatia, .
Proceedings Volume 12777, International Conference on Space Optics — ICSO 2022; 127773A (2023)
https://doi.org/10.1117/12.2690347 (Open Access)

Baer, P., Elshani, A., Reiter, M., Cebeci, P., Giesberts, M., Ebert, J., Hoefer, M., Hoffmann, D.:
Thulium- and Holmium-doped high stability fiber amplifiers at 2 µm for next generation gravitational wave detectors.
SPIE LASE, 2023, San Francisco, California, United States. Proceedings Volume 12400, Fiber Lasers XX: Technology and Systems; 124000J (2023)
https://doi.org/10.1117/12.2649611

Cebeci, P., Giesberts, M., Baer, P., Eßer, J., Gützlaff, J., Hoffmann, H.-D., Dahl, K.:
Highly stable fiber amplifier development and environmental component-testing for the space-based gravitational wave detector LISA.
SPIE LASE, 28.1-2.2. 2023 , San Francisco CA, United States, California, United States. Proceedings Volume 12400, Fiber Lasers XX: Technology and Systems; 124001H (2023)
https://doi.org/10.1117/12.2649881

Sider, A., Di Fronzo, C., Amez-Droz, L., Amorosi, A., Badaracco, F., Baer, P., Bertolini, A., Bruno, G., Cebeci, P., Collette, C., Ebert, J., Erben, B., Esteves, R., Ferreira, E., Gatti, A., Giesberts, M., Hebbeker, T., van Heijningen, J., Hennig, J., Hennig, M., Hild, S., Hoefer, M., Hoffmann, H., Jacques, L., Jamshidi, R., Joppe, R., Kuhlbusch, T., Lakkis, M., Lenaerts, C., Locquet, J., Loicq, J., Le Van, B., Loosen, P., Nesladek, M., Reiter, M., Stahl, A., Steinlechner, J., Steinlechner, S., Tavernier, F., Teloi, M., Vilaboa Pérez, J., Zeoli, M.:
E-TEST: a compact low-frequency isolator for a large cryogenic mirror.
Classical and Quantum Gravity 40(16), 165002- (2023)
http://dx.doi.org/10.1088/1361-6382/ace230 (Open Access)

Baer, P., Cebeci, P., Giesberts, M., Hoffmann, H-D., Loosen, P., ETpathfinder Konsortium,:
ETpathfinder: a cryogenic testbed for interferometric gravitational-wave detectors.
Classical and Quantum Gravity 39(21), (2022)
https://doi.org/10.1088/1361-6382/ac8fdb (Open Access)

Baer, P., Cebeci, P., Giesberts, M., Hoffmann, D.:
High stability fiber amplifiers for terrestrial and space sensing applications at 1 and 2 µm.
Optica Advanced Photonics Congress 2022, 25-28 Juni 2022, Busan, South Korea. Application of Lasers to Sensing and Free Space Communication (LS&C).
Technical Digest Series (Optica Publishing Group, 2022), LsM6C.6, (2022)
https://doi.org/10.1364/LSC.2022.LsM6C.6

Baer, P., Klein, S., Raguse, M., Giesberts, M., Reiter, M., Hoffmann, D.:
Monolithic highly Multi-Mode XLMA-Fiber Resonator for High Power Operation.
OPTICS EXPRESS 30(19), 33842-33849 (2022)
https://doi.org/10.1364/OE.464861 (Open Access)

Raguse, M., Klein, S., Baer, P., Giesberts, M., Traub, M., Hoffmann, H-D.:
Investigations on high-reflective Fiber-Bragg-Gratings in multimode fibers.
OSA Continuum 1(5), 965-973, (2022)
https://doi.org/10.1364/OPTCON.450150 (Open Access)

Baer, P., Klein, S.; Raguse, M., Reiter, M., Giesberts, M., Fitzau, O., Hoffmann, H.-D:
Highly reflective Fiber Bragg Gratings in active Fibers for fiber-integrated Multi-Mode Resonators.
SPIE LASE, 2022, San Francisco, California, United States, 22 January -28. February 2022.
Proceedings Volume 11981, Fiber Lasers XIX: Technology and Systems, 1198114 - (5 S.) (2022)
https://doi.org/10.1117/12.2606583

Betz, P., Eßer, J., Gräfe, C., Plum, J. B.:
Temperature systems based on Peltier-elements for the use in a Thermal Vacuum Chamber and a Bakeout Facility for space laser components.
50th International Conference on Environmental Systems ICES, 12.-15. July 2021, virtuel only. Proceedings
https://hdl.handle.net/2346/87079

Baer, P., Giesberts, M., Fitzau, O.:
Investigations on single-mode fibers with rectangular core geometry
OSA Continuum, Vol. 3, Issue 8, pp. 2243-2252 (2020)
https://doi.org/10.1364/OSAC.396103

Cebeci, P., Vera Mosquera, J., Höfer, M., Fitzau, O., Giesberts, M., Erben, B., Hoffmann, H.,
Highly stable, high power hybrid fiber and Innoslab amplifier for narrow linewidth signals.
SPIE LASE, 1-6 February 2020, San Francisco, California, United States.
Proceedings Volume 11259, Solid State Lasers XXIX: Technology and Devices; 112590L (2020)
http://dx.doi.org/10.1117/12.2545934

Fitzau, O.:
Fasergekoppelte optische Isolatoren für Hochleistungs-Faserlaser
Ergebnisse aus der Lasertechnik, Apprimus Verlag (2020)

Klein, S., Giesberts, M., Baer, P., Raguse, M., Fitzau, O., Traub, M., Hoffmann, H.-D., Krause, V., Rehmann, G.:
Fiber Bragg gratings in active multimode XLMA fibers for high-power kW-class fiber lasers.
SPIE LASE, 01-06 Feb. 2020, San Francisco, California, United States. Proceedings Volume 11260, Fiber Lasers XVII: Technology and Systems, 1126025 (2020)
https://doi.org/10.1117/12.2545738

Baer, P., Cebeci, P., Giesberts, M., Fitzau, O.:
Design and fabrication of a fused 7 x 1 35/50 µm into 125/250 µm fiber combiner
OSA Continuum, Vol. 2, Issue 4, pp. 1106-1112 (2019)
https://doi.org/10.1364/OSAC.2.001106

Dahl, K., Cebeci, P., Fitzau, O. Giesberts, M., Greve, C., Kruztik, M., Peters, A., Amairi Pyka, S., Sanjuan, J., Schiemangk, M., Schuldt, T., Voss, K., Wicht, A.:
A new laser technology for LISA
Proc. SPIE 11180, International Conference on Space Optics — ICSO 2018, 111800C (12 July 2019)
https://doi.org/10.1117/12.2535931

Fitzau, O., Betz, P., Cebeci, P., Giesberts, M., Hoffmann, D., Schiemangk, M., Wicht, A., Sanjuan, J., Dahl, K., Amairi Pyka, S., Kovalchuk, E., Peters, A.:
Highly stable fiber lasers for satellite-based gravitational measurements
Proc. SPIE 10897, Fiber Lasers XVI: Technology and Systems, 108972H (7 March 2019)
https://doi.org/10.1117/12.2509950

Greve, C., Dahl, K., Barwood, G., Cebeci, P., Deutsch, C., Fitzau, O., Giesberts, M., Ghulinyan, M.,  Gill, P., Kassner, B., Koller, S., Krutzik, M., Kundermann, S., Le Goff, R., Oswald, M., Peters, A., Pyka Amairi, S., Sanjuan, J., Schiemangk, M., Schilt, S., Schuldt, T., Sell, A., Stenzel, C., Voss, K., Wicht, A., Zhukov, A.:
Space based lasers for gravitational wave detection
Laser Applications Conference 2019 (ASSL, LAC, LS&C), 2019
https://doi.org/10.1364/LAC.2019.CM3C.4

Klein, S., Fitzau, O., Giesberts, M., Traub, M., Hoffmann, D., Krause, V., Rehmann, G.:
Investigation of fiber Bragg gratings for high-power multi-mode XLMA-based fiber lasers
Proc. SPIE 10897, Fiber Lasers XVI: Technology and Systems, 1089713 (7 March 2019)
https://doi.org/10.1117/12.2508385

Langner, A., Moser, F., Plass, J., Schönfeld, D., Schötz, G., Brabant, T., Kuka, G., Giesberts, M., Baer, P., Klein, S., Fitzau, O., Hoffmann, D., Rehmann, G., Krause, V.:
Improvement of the manufacturing process chain of sintered active XLMA fibers and their preforms for use in high power, high efficiency fiber resonators
Proc. SPIE 10897, Fiber Lasers XVI: Technology and Systems, 108970F (7 March 2019)
https://doi.org/10.1117/12.2508597

Giesberts, M., Fitzau, O., Hoffmann, D., Lange, R., Bachert, C., Krause, V.:
Directly q-switched high power resonator based on XLMA-fibers
Proc. SPIE 105122, Fiber Lasers XV: Technology and Systems, 1051218 (26 February 2018)
https://doi.org/10.1117/12.2287783

Lange, R., Bachert, C., Rehmann, G., Weber, H., Luxen, R.,Enns, H.,Schenk, M., Hosdorf, S., Marfels, S., Bay, M., Kösters, A., Krause, V., Giesberts, M., Fitzau, O., Hoffmann, H.-D.:
Fully integrated Q-switch for commercial high-power resonator with solitary XLMA-fiber.
SPIE LASE, 27 January-1 February 20182018, San Francisco, California, United States.
Proceedings Volume 10512, Fiber Lasers XV: Technology and Systems, 1051217, (7 S.) (2018)
https://doi.org/10.1117/12.2288309

Dahl, K., Nicklaus, K., Herding, M., Wang, X., Beller, N., Fitzau, O. Giesberts, M., Herper, M., Williams, R.A., Barwood, G.P., Lovelock, P., Gill, P., Koegel, H., Sell, A.:
High stability laser for interferometric earth gravity measurements
Proc. SPIE 10562, International Conference on Space Optics — ICSO 2016, 105620J (25 September 2017)
https://doi.org/10.1117/12.2296095

Neumann, A., Giesberts, M., Witte, U., Fitzau, O., Hoffmann, H.-D.:
Analytical model for diode-to-fiber coupling and beam propagation in weakly guiding fibers.
2017 IEEE High Power Diode Lasers and Systems Conference (HPD), 11 Oct - 12 Oct 2017, Coventry, UK.
Proc. IEEE High Power Diode Lasers & Systems, 35-36 (2017)
http://dx.doi.org/10.1109/HPD.2017.8261091

Löhring, J., Winzen, M., Faidel, H., Miesner, J., Plum, D., Klein, J. Fitzau, O., Giesberts, M., Brandenburg, W., Seidel, A., Schwanen, N., Riesters, D., Hengesbach, S., Hoffmann, D.:
Key optical components for spaceborne lasers
Proc. SPIE 9730, Components and Packaging for Laser Systems II, 97300O (22 April 2016)
https://doi.org/10.1117/12.2212319

Fitzau, O.:
Polarized fiber lasers and amplifiers
Springer Series in Optical Sciences. Vol. 189, 251-263 (2015)

Herper, M., Fitzau, O., Giesberts, M., Nicklaus, K., Barwood, G. P., Williams, R. A., Gill, P., Koegel, H., Hoffmann, D.:
High stability single-frequency Yb fiber amplifier for next generation gravity missions
Proc. SPIE 9344, Fiber Lasers XII: Technology, Systems, and Applications, 93440B (4 March 2015)
https://doi.org/10.1117/12.2077400

Mingareev, I., Gehlich, N., Bonhoff, T., Abdulfattah, A., Sincore, A. M., Kadwani, P., Shah, L., Richardson, M.:
Principles and applications of trans-wafer processing using a 2-µm thulium fiber laser
Int. J. Adv. Manuf. Technol. (Online first) (12 S.) (2015)

Becker, M., Werner, M., Fitzau, O., Esser, D., Kobelke, J.: Lorenz, A., Schwuchow, A., Rothhardt, M., Schuster, K., Hoffmann, D., Bartelt, H.:
Laser-drilled free-form silica fiber preforms for microstructured optical fibers
Opt. Fiber Technol. 19 (5), 482-485 (2013)

Becker, M., Werner, M., Fitzau, O., Esser, D., Kobelke, J., Schuster, K., Lorenz, A., Schwuchow, A., Rothhardt, M., Hoffmann, D., Bartelt, H.:
Laser processed preforms for microstructured optical fibers
Proc. SPIE 8785, 8785C9 (8 S.) (2013)

Larsen, C., Giesberts, M., Nyga, S., Fitzau, O., Jungbluth, B., Hoffmann, D., Bang, O.:
Gain-switched all-fiber laser with narrow bandwidth
Optics Express, Vol. 21, Issue 10, pp. 12302-12308 (2013)
https://doi.org/10.1364/OE.21.012302

Katzy, V., Giesberts, M., Fitzau, O., Hoffmann, D.:
Single mode all-fiber pulse-pumped Raman amplifier for picosecond pulses
Advanced Solid-State Photonics (ASSP), San Diego, California, Jan. 29^th - Feb. 1^st, 3 S., 2012

Fitzau, O., Geiger, J., Hoffmann, H.D.:
Experimental and theoretical studies on kW class polarized fiber lasers for cw operation
Proc. SPIE
7195, 719509 (9 S.), 2009

Giesberts, M.; Geiger, J., Traub, M., Hoffmann, H.-D.:
Novel design of a gain-switched diode-pumped fiber laser
Proc. SPIE 7195, 71952P (9 S.), 2009

Geiger, J., Fitzau, O., Zintzen, B., Hoffmann, D.:
Single-mode, highly polarized Y1456b-doped fiber laser with 850 W output power
ASSP 2008, Nara, Japan, Jan 27-30,(3 S.), 2008

Zintzen, B., Emmerich, A., Geiger, J., Hoffmann, D., Loosen, P.:
Effective cooling for high-power fiber lasers
Proc. of the 4th Int. WLT-Conf. on Lasers in Manufacturing , Munich, June 2007
(5 S.), 2007

Zintzen, B., Langer, T., Geiger, J., Hoffmann, D., Loosen, P.:
Heat transport in solid and air-clad fibers for high-power fiber lasers
Opt. Expr.
15, 16787-16793, 2007

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