On the initiation of fiber fuse damage in high-power ytterbium-doped fiber lasers

Fiber fuse effect can occur spontaneously and propagate along optical fibers to cause widespread damage; it threatens all applications involving optical fibers. This paper presents two results. First, it establishes that the initiation of fiber fuse (IFF) in silica fibers is caused by virtual-defect-induced absorption. Critical temper-atures and critical optical powers for IFF are simulated for the first time using a 3D solid-state heat transfer model with heat source generated by the virtual-defect-induced absorption. In this method, formation energies of the virtual defects can be uniquely determined, which offers critical information on the chemical reasons for fiber fuse. Second, this paper offers a method to evaluate operating temperatures of fiber lasers. General analytical solutions of the operating temperatures along gain fibers are deduced. Results of 976-nm laser-diode-pumped and 1018-nm tandem-pumped ytterbium-doped fiber (YDF) amplifiers using 10/130-mu m YDFs are calculated. Potential limits caused by fiber fuse are discussed.(c) 2022 Chinese Laser Press

Automated summary

This paper presents the simulation of critical temperatures and critical optical powers for fiber fuse using a 3D solid-state heat transfer model, and it identifies the impact of formation energies of virtual defects on fiber fuse. Additionally, a method to evaluate the operating temperatures of fiber lasers is proposed.