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

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.

50^th International Conference on Environmental Systems ICES, 12.-15. July 2021

https://hdl.handle.net/2346/87079

Cebeci, P., Mosquera, J.V., Höfer, M., Fitzau, O., Giesberts, M., Erben, B., Hoffmann, D.:

Highly stable, high power hybrid fiber and Innoslab amplifier for narrow linewidth signals

Proc. SPIE 11259, Solid Stage Lasers XXIX: Technology and Devices, 112590L (4 March 2020)

https://doi.org/10.1117/12.2545934

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

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

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^st February 2020)

https://doi.org/10.1117/12.2545738

Fitzau, O.:

Fasergekoppelte optische Isolatoren für Hochleistungs-Faserlaser

Ergebnisse aus der Lasertechnik, Apprimus Verlag (2020)

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

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

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

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., Köster, A., Krause, V., Giesberts, M., Fitzau, O. Hoffmann, D.:

Fully integrated Q-switch for commercial high-power resonator with solitary XLMA-fiber

Proc. SPIE 10512, Fiber Lasers XV: Technology and Systems, 1051217 (26 February 2018)

https://doi.org/10.1117/12.2288309

Neumann, A., Giesberts, M. Witte, U., Fitzau, O., Hoffmann, D.:

Analytical model for diode-to-fiber coupling and beam propagation in weakly guiding fibers

IEEE High Power Diode Lasers and Systems Conference (HPD), 11-12 Oct. 2017

https://doi.org/10.1109/HPD.2017.8261091

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

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, P. 251-263 (2015)

http://doi.org/10.1007/978-1-4939-1179-0_11

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

Becker, M., Werner, M. Fitzau, O., Esser, D., Kobelke, J., LLorenz, A., Schwuchow, A., Rothhardt, M., Schuster, K., Hoffmann, D., Hartmut, B.:

Laser-drilled free-form silica fiber preforms for microstructured optical fibers

Optical fiber Technology Vol 19, Issue 5, P. 482-485, Oct. 2013

https://doi.org/10.1016/j.yofte.2013.06.001

Becker, M., Werner, M. Fitzau, O., Esser, D., Kobelke, J., LLorenz, A., Schwuchow, A., Rothhardt, M., Schuster, K., Hoffmann, D., Hartmut, B.:

Laser processed preforms for microstructured optical fibers

Proc. SPIE 8785, 8^th Iberoacmerican Optics Meeting and 11^th Latin American Meeting on Optics, Lasers and Applications, 18. Nov. 2013

https://doi.org/10.1117/12.2023223

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. - Feb. 1. 2012

https://doi.org/10.1364/ASSP.2012.AT4A.6

Fitzau, O., Geiger, J., Hoffmann, D.:

Experimental and theoretical studies on kW class polarized fiber lasers for cw operation

Proc. SPIE 7195, Fiber Lasers VI: Technology, Systems, and Applications, 719509 (19 February 2009)

https://doi.org/10.1117/12.812112

Giesberts, M., Geiger, J., Traub, M., Hoffmann, D.:

Novel design of a gain-switched diode-pumped fiber laser

Proc. SPIE 7195, Fiber Lasers VI: Technology, Systems, and Applications, 71952P (19 February 2009)

https://doi.org/10.1117/12.807721

Geiger, J., Fitzau, O., Zintzen, B., Hoffmann, D.:

Single-mode, highly polarized Yb-doped fiber laser with 850 W output power

Advanced Solid-State Photonics 2008, Nara Japan, 27.-30. January 2008

https://doi.org/10.1364/ASSP.2008.WA7

Zintzen, B., Langer, T., Geiger, G., Hoffmann, D., Loosen, P.:

Heat transport in solid and air-clad fibers for high-power fiber lasers

Optics Express, Vol. 25, Issue 25, pp. 16787-16793 (2007)

https://doi.org/10.1364/OE.15.016787

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