The temporal behavior of mode instabilities in active large mode area fibers is experimentally investigated in detail. Thus, apart from the onset threshold of mode instabilities, the output beam is characterized using both high-speed camera measurements with 20,000 frames per second and photodiode traces. Based on these measurements, an empiric definition of the power threshold of mode instabilities is introduced. Additionally, it is shown that the temporal dynamics show a transition zone between the stable and the unstable regimes where well-defined periodic temporal fluctuations on ms-timescale can be observed. Finally, it is experimentally shown that the larger the mode-field area, the slower the mode-instability fluctuation is. The observations support the thermal origin of mode instabilities.
© 2012 OSAFull Article | PDF Article
Tino Eidam, Christian Wirth, Cesar Jauregui, Fabian Stutzki, Florian Jansen, Hans-Jürgen Otto, Oliver Schmidt, Thomas Schreiber, Jens Limpert, and Andreas Tünnermann
Opt. Express 19(14) 13218-13224 (2011)
Fabian Stutzki, Hans-Jürgen Otto, Florian Jansen, Christian Gaida, Cesar Jauregui, Jens Limpert, and Andreas Tünnermann
Opt. Lett. 36(23) 4572-4574 (2011)
Cesar Jauregui, Tino Eidam, Hans-Jürgen Otto, Fabian Stutzki, Florian Jansen, Jens Limpert, and Andreas Tünnermann
Opt. Express 20(12) 12912-12925 (2012)