학술논문
Transverse Mode Instabilities in kW-class Tm-doped Fiber Amplifier
Document Type
Conference
Author
Source
2023 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC), 2023 Conference on. :1-1 Jun, 2023
Subject
Language
ISSN
2833-1052
Abstract
Transverse Mode Instabilities (TMI) are a thermally-induced nonlinear effect that results in a fluctuating output beam profile unsuited for most applications. Since their first observation in Yb-doped amplifiers [1], TMI have manifested as major limitation in scaling the average output power of high-power fiber lasers. In 2021, TMI have been observed in Tm-doped fiber amplifiers as well [2], [3]. Recently, Anderson et al. presented 1.1 kW at 1950 nm [3] and 905 W at 2040 nm [4] in Tm-doped fiber amplifiers in 20/400μm geometry, both pumped with diode lasers of a wavelength around 794 nm. Their experiments with 25/400μm Tm-doped fibers were TMI-limited around 600 – 700 W [4] and dependencies on the active fiber length were investigated [4]. In our contribution we will present the dependence of the TMI-threshold on the pump wavelength, as has been done for Yb amplifiers [5]. Furthermore, we will show that Tm-doped fiber amplifiers in 25/400μm geometry can be scaled TMI-free beyond 700 W.