Fiber fuse behavior in kW-level continuous-wave double-clad field laser

Abstract

In this study, original experimental data for fiber fuse in kW-level continuous-wave (CW) high power double-clad fiber (DCF) laser are reported. The propagating velocity of the fuse is 9.68 m/s in a 3.1-kW Yb-doped DCF laser. Three other cases in Yb-doped DCF are also observed. We think that the ignition of fiber fuse is caused by thermal mechanism, and the formation of bullet-shaped tracks is attributed to the optical discharge and temperature gradient. The inducements of initial fuse and formation of bullet-shaped voids are analyzed. This investigation of fiber fuse helps better understand the fiber fuse behavior, in order to avoid the catastrophic destruction caused by fiber fuse in high power fiber laser.

Fiber Fuse Simulation in Double-Clad Fibers for High-Power Fiber Lasers

“…The average propagation velocity V f is estimated to be 9.07 m/s using these data. This V f of the DCF10 is close to the value of 8.75 m/s measured by Sun et al [69].…”

“…Fiber fuse was observed in Yb-doped DCFs operated in a master oscillator power amplifier (MOPA) configuration [65,[68][69][70]. Wang et al reported that the fiber fuse was initiated at the fiber end surface through physically adhered wet-alumina particles and/or the clusters of them interacting with high-power laser light in the core region [65].…”

Exploring the initiation of fiber fuse

“…1050 °C) 8,10,11 in optical fibers lead to uncontrolled increase of optical absorption, which further increase the temperature and finally decompose the fiber cores in a chain-reaction manner. Empirically, the assumption agreed with that fiber fuses were more often observed in fiber systems transmitting high average optical powers, where thermal effects accompany light-matter-interactive devices therein 6,12 . However, no specific temperature conditions were experimentally verified to trigger fiber fuse yet.…”

“…It proves threatening both continuous-wave and pulse 11,12 laser systems. But it contrasts with the conventional laser-induced damages 19 for its much lower threshold optical power (~MW/cm2 for single-mode glass fibers 2,6–8,12 or ~kW/cm 2 for polymer fibers 5,9 ). The very-low thresholds allow fiber fuse, once it is initiated, to destroy the whole fiber systems.…”

“…The very-low thresholds allow fiber fuse, once it is initiated, to destroy the whole fiber systems. For example, fiber fuse has become the most common and catastrophic kind of damages in high-power fiber laser systems 6 , causing uncharted economical losses. As the use of optical fibers prevails in many branches of physical researches and engineering, preventing spontaneous fiber fuses becomes an urgent request.…”