Mitigation of transverse mode instability with travelling waves in high-power fiber amplifiers
Jauregui C, Stihler C, Tu Y, Kholaif S, Limpert J (2020)
Publication Type: Conference contribution
Publication year: 2020
Journal
Publisher: SPIE
Book Volume: 11260
Conference Proceedings Title: Proceedings of SPIE - The International Society for Optical Engineering
Event location: San Francisco, CA, USA
ISBN: 9781510632837
DOI: 10.1117/12.2543383
Abstract
In this work we present a novel way to mitigate the effect of transverse mode instability in high-power fiber amplifiers. In this technique a travelling wave is induced in the modal interference pattern by seeding the amplifier with two modes that have slightly different frequencies. The interference pattern thus formed will travel up-or downstream the fiber (depending on the sign of the frequency difference between the modes) with a certain speed (that depends on the absolute value of the frequency difference). If the travelling speed is chosen properly, the thermally-induced index grating will follow the travelling modal interference pattern creating a constant phase shift between these two elements. Such a constant controllable phase shift allows for a stable energy transfer from the higher-order modes to the fundamental mode or viceversa. Thus, this technique can be adjusted in such a way that, at the output of the fiber almost all the energy is concentrated in the fundamental mode, regardless of the excitation conditions. Moreover, this technique represents one of the first examples of the new family of mitigation strategies acting upon the phase shift between the modal interference pattern and the refractive index grating. Additionally, it even exploits the effect of transverse mode instability for gaining control over the beam profile at the output of the amplifier. Therefore, by adjusting the frequency difference between the seed modes, it is possible to force that the beam at the output acquires the shape of the fundamental mode or that of a higher order mode.
Involved external institutions
Germany (DE)How to cite
APA:
Jauregui, C., Stihler, C., Tu, Y., Kholaif, S., & Limpert, J. (2020). Mitigation of transverse mode instability with travelling waves in high-power fiber amplifiers. In Liang Dong (Eds.), Proceedings of SPIE - The International Society for Optical Engineering. San Francisco, CA, USA: SPIE.
MLA:
Jauregui, Cesar, et al. "Mitigation of transverse mode instability with travelling waves in high-power fiber amplifiers." Proceedings of the Fiber Lasers XVII: Technology and Systems 2020, San Francisco, CA, USA Ed. Liang Dong, SPIE, 2020.
BibTeX: Download