Open AccessExperimental investigation of quasi-static mode degradation in a high power large mode area fiber amplifier
Author(s) -
Li Xie,
Chun Zhang,
Yu Liu,
Haokun Li,
Qiuhui Chu,
Huaqing Song,
Wenjie Wu,
Biao Shen,
Min Li,
Xi Feng,
Shan Huang,
Rumao Tao,
Jianjun Wang,
Xiaoming Zhang,
Heyuan Zhu
Publication year - 2021
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.415690
Subject(s) - photodarkening , optics , amplifier , materials science , fiber laser , fiber , power (physics) , amplified spontaneous emission , degradation (telecommunications) , optical fiber , optoelectronics , laser , physics , electronic engineering , cmos , quantum mechanics , composite material , engineering
In this work, quasi-static mode degradation in high power fiber amplifiers has been investigated experimentally. An increase of M 2 from 1.3 to 2.6 with distortion of the beam profile is observed, which results in the signal spectra and backward light characterization departing from the traditional phenomena. The amplifier has been operated at the same input pump power of 705 W for nearly 2.2 hours to investigate the relationship between quasi-static mode degradation and photodarkening. The evolution of M 2 factor/beam profile, mode correlation coefficient and output laser power at different working times indicate that the quasi-static mode degradation in the high power fiber amplifiers is dependent on photodarkening and evolves on the scale of tens of minutes. A visible green light has been injected to photobleach the gain fiber for 19 hours, which reveals that the quasi-static mode degradation has been suppressed simultaneously. To the best of our knowledge, this is the first detail report of photodarkening-induced quasi-static degradation in high power fiber amplifiers.