Open AccessModeling of transient modal instability in fiber amplifiers
Author(s) -
Benjamin G. Ward
Publication year - 2013
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.21.012053
Subject(s) - instability , optics , amplifier , transient (computer programming) , modal , optical fiber , physics , mode volume , fiber laser , polarization maintaining optical fiber , materials science , fiber optic sensor , mechanics , optoelectronics , computer science , cmos , polymer chemistry , operating system
A model of transient modal instability in fiber amplifiers is presented. This model combines an optical beam propagation method that incorporates laser gain through local solution of the rate equations and refractive index perturbations caused by the thermo-optic effect with a time-dependent thermal solver with a quantum defect heating source term. This model predicts modal instability a fiber amplifier operating at 241, 270, and 287 Watts of output power characterized by power coupling to un-seeded modes, the presence of stable and unstable regions within the fiber, and rapid intensity variations along the fiber. The instability becomes more severe as the power is increased.