Numerical modeling of the thermally induced core laser leakage in high power co-pumped ytterbium doped fiber amplifier

Abstract

We propose a novel model to explain the physical process of the thermally induced core laser leakage (TICLL) effect in a high power co-pumped ytterbium doped fiber (YDF) amplifier. This model considers the thermally induced mode bending loss decrease and the thermally induced mode instability (TMI) in the coiled YDF, and is further used to reproduce the TICLL effect in the high power co-pumped step-index $20/400$ fiber amplifier. Besides, the TICLL effect in the co-pumping scheme and counter-pumping scheme is compared. The result proves that the TICLL effect is caused by the combined effect of the thermally induced mode bending loss decrease and the TMI, and could be mitigated by adopting the counter-pumping scheme. To our best knowledge, this is the first theoretical explanation of the TICLL effect in high power fiber amplifier.

Editorial: HPLSE special issue on fibres for high-power lasers

“…kW-class high power fiber laser enabled by active long tapered fiber [1] 2. Numerical modeling of the thermally induced core laser leakage in high power co-pumped ytterbium doped fiber amplifier [2] 3. Monolithic high-average-power linearly polarized nanosecond pulsed fiber laser with near-diffractionlimited beam quality [3] 4.…”

“…• Large mode area fibres for power scaling Submissions for this special issue cover from the development of active fibres itself to the advances in fibre lasers and fibre amplifiers. Papers described research on high-power ytterbium-doped fibre lasers and amplifiers operating in continuous wave [1,2] , nanosecond regime [3] , picosecond regime [4] and femtosecond regime [5] ; erbiumdoped tunable fibre amplifier [6] ; Raman fibre laser [7,8] and nonlinear amplifier [9] ; high harmonic generation for UV Correspondence to: Y. Wang, Institute of Laser Engineering, Beijing University of Technology, Beijing 100124, China. Email: wangyingying@bjut.edu.cn wavelength [10] as well as a review of ytterbium-doped fibres [11] .…”

“…Optimizing the nonlinearity in the dissipative-soliton mode-locked fibre laser allows the scale up of the pulse energy in the sub-100 fs fibre lasers [5] . The thermal effect limiting the power scaling of fibre laser sources with high beam quality has also been investigated by a novel model [2] .…”

“…Special issue content kW-class high power fiber laser enabled by active long tapered fiber [1] Numerical modeling of the thermally induced core laser leakage in high power co-pumped ytterbium doped fiber amplifier [2] Monolithic high-average-power linearly polarized nanosecond pulsed fiber laser with near-diffraction-limited beam quality [3] High pulse energy fiber/solid-slab hybrid picosecond pulse system for material processing on polycrystalline diamonds [4] Nonlinearity optimization of dissipative-soliton fiber laser for generation of pulses with 350 kW peak power [5] 10 watt-level tunable narrow linewidth all-fiber amplifier [6] Power scaling on tellurite glass Raman fibre lasers for mid-infrared applications [7] Investigation on extreme frequency shift in silica fiber-based high-power Raman fiber laser [8] Towards high power nonlinear fiber amplifier [9] Efficient high harmonics generation by enhancement cavity driven with a post-compressed FCPA laser at 10 MHz [10] Development and prospect of high-power doped fibers [11] …”

“…Numerical modeling of the thermally induced core laser leakage in high power co-pumped ytterbium doped fiber amplifier [2]…”