2015/03/25 by Jianlong Yang, Yao Wang, Yang, Jianlong +5 · 1 citation
Engineering · Physics and Astronomy · #Advanced Fiber Laser Technologies #FOS: Physical sciences #Optics (physics.optics) #Photonic Crystal and Fiber Optics #Solid State Laser Technologies
paper · pdf · doi:10.48550/arxiv.1503.07256
openalex publication_date 2015/03/25 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Thermal effects are critical constrains for developing high-power thulium-doped fiber lasers (TDFLs). In this paper, we numerically investigate the lasing and thermal characteristics of the TDFLs under different pump transitions. Our results show, the widely-used pump transition 3H6→3H4, taking advantages of high-power high-efficiency laser diodes at ∼0.8 μm, may not be a superior choice for directly outputting multi-kilowatt at 2 μm because of severe thermal problems. Meanwhile, using other pump transitions resulting 2-μm emissions, especially the in-band pump transition 3H6→3F4, will decrease the generated heat to a large extent. By optimizing the power filling factor of the gain fiber, we find a 2-μm TDFL cladding-pumped at 1.9 μm will lead to the laser slope efficiency close to its quantum efficiency (95%). The induced ultra-low quantum defect would be of great importance for power scaling. We thus propose tandem-pumped TDFLs for reducing the heat at high powers and discuss the related issues of design. Besides, we also explore the differences of the thermal characteristics between laser and superfluorescent operations, which will contribute to deepening the understanding of the thermal effects in high-power thulium-doped fiber amplifiers.