Open AccessThe influence of index-depressions in core-pumped Yb-doped large pitch fibers
Author(s) -
Florian Jansen,
Fabian Stutzki,
Hans-Jürgen Otto,
Martin Baumgartl,
César Jáuregui,
Jens Limpert,
Andreas Tünnermann
Publication year - 2010
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.18.026834
Subject(s) - photonic crystal fiber , optics , core (optical fiber) , materials science , photonics , fiber , mode (computer interface) , photonic crystal , mode volume , doping , refractive index , optical fiber , optoelectronics , graded index fiber , physics , computer science , fiber optic sensor , composite material , operating system
Rare-earth doped photonic crystal fibers rely ideally on an index matching of the doped core to the surrounding glass to work properly. Obtaining a perfect index matching is technologically very challenging, and fiber manufacturers opt for targeting an index depression instead, which still ensures the influence of the photonic structure on the light propagation. In this paper the analysis of the influence of this core index depression on the higher-order mode discrimination and on the beam quality of the fundamental mode of different designs of core-pumped active large pitch photonic crystal fibers is discussed. The most promising design is evaluated in terms of mode area scaling with a view to mode field diameters above 100 µm. Detailed requirements on the accuracy of the core index matching are deduced.