Power scaling of single-frequency Yb³⁺ fiber amplifiers with highly absorbing standard LMA fibers

verfasst von

Kristopher Kruska, Phillip Booker, Peter Weßels, Jörg Neumann, Dietmar Kracht

Abstract

Standard large mode area (LMA) fibers are the state-of-the-art technology for single-frequency fiber amplifiers at 1064 nm and exhibit great power efficiency and superior beam quality. Next generation gravitational wave detectors (GWD) show an increasing demand for laser power. The output power of single-frequency fiber amplifiers is usually limited by nonlinear effects such as stimulated Brillouin scattering (SBS). One way to increase the SBS threshold is to decrease the used fiber length, which can be achieved using standard LMA fibers with an increased pump absorption. A trade-off between short lengths on the one hand and sufficient pump absorption on the other hand must be assessed. In the past, we have demonstrated single-frequency fiber amplifiers based on commercial off-the-shelf step index, polarization maintaining, double clad LMA fibers delivering more than 200 W. For the increased power demands of the European next generation GWD, the Einstein Telescope, we are evaluating the same fiber, but with a nominally doubled pump absorption, thus enabling shorter fiber lengths. We present a comparison between forward and backward pumped amplifiers. The SBS threshold of the forward pumped amplifier could already be raised to around 200 W output power despite being forward pumped and having no further SBS mitigation techniques applied. Switching to backward pumping, we will discuss the SBS threshold for different amplifier setups, compare the results with simulations and assess, whether further power scaling with this fiber is feasible.

Organisationseinheit(en)

QuantumFrontiers
Institut für Photonik

Externe Organisation(en)

Laser Zentrum Hannover e.V. (LZH)

Typ

Aufsatz in Konferenzband

Anzahl der Seiten

6

Publikationsdatum

09.04.2025

Publikationsstatus

Veröffentlicht

Peer-reviewed

Ja

ASJC Scopus Sachgebiete

Elektronische, optische und magnetische Materialien, Physik der kondensierten Materie, Angewandte Informatik, Angewandte Mathematik, Elektrotechnik und Elektronik

Elektronische Version(en)

https://doi.org/10.1117/12.3042910 (Zugang: Geschlossen)