Open AccessEnhanced pump absorption efficiency in coiled and twisted double-clad thulium-doped fibers
Author(s) -
Pavel Koška,
Pavel Peterka,
Jan Aubrecht,
Ondřej Podrazký,
Filip Todorov,
Martin Becker,
Yauhen Baravets,
Pavel Honzátko,
Ivan Kašı́k
Publication year - 2016
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.24.000102
Subject(s) - materials science , fiber laser , thulium , optics , fiber , absorption (acoustics) , slope efficiency , optical fiber , dispersion shifted fiber , doping , double clad fiber , graded index fiber , optoelectronics , composite material , fiber optic sensor , physics
Results of the first experimental demonstration of the recently proposed technique for improvement of the pump absorption in double-clad fibers by their simultaneous coiling and twisting are reported. The peak absorption (14 dB) of 3-m long hexagonal thulium-doped fiber was increased by 8 dB by its simultaneous coiling and twisting. Explanation of the effect is given by numerical modelling of the pump absorption in hexagonal and panda-type double-clad fibers. Improvement of fiber laser performance was also proved. The slope efficiency increased from 19.6% of the straight fiber to 23.9% of the coiled only fiber and 29.4% of the simultaneously coiled and twisted fiber.