Open AccessTemperature-induced index gratings and their impact on mode instabilities in high-power fiber laser systems
Author(s) -
César Jáuregui,
Tino Eidam,
Hans-Jürgen Otto,
Fabian Stutzki,
Florian Jansen,
Jens Limpert,
Andreas Tünnermann
Publication year - 2011
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.20.000440
Subject(s) - optics , grating , fiber bragg grating , long period fiber grating , interference (communication) , physics , context (archaeology) , fiber laser , mode volume , equilibrium mode distribution , radiation mode , mode (computer interface) , materials science , single mode optical fiber , optical fiber , graded index fiber , fiber optic sensor , telecommunications , paleontology , channel (broadcasting) , biology , computer science , operating system
Mode-interference along an active fiber in high-power operation gives rise to a longitudinally oscillating temperature profile which, in turn, is converted into a strong index grating via the thermo-optic effect. In the case of mode beating between the fundamental mode and a radially anti-symmetric mode such a grating exhibits two periodic features: a main one which is radially symmetric and has half the period of the modal beating, and a second one that closely follows the mode interference pattern and has its same period. In the case of modal beating between two radially symmetric modes the thermally induced grating only has radially symmetric features and exhibits the same period of the mode interference. The relevance of such gratings in the context of the recently observed mode instabilities of high-power fiber laser systems is discussed.