Berlin 2008 – wissenschaftliches Programm

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DY: Fachverband Dynamik und Statistische Physik

DY 7: Time-delayed feedback and neural networks

DY 7.1: Vortrag

Montag, 25. Februar 2008, 16:30–16:45, A 053

Stabilizing continuous-wave output in semiconductor lasers by time-delayed feedback methods — •Thomas Dahms, Philipp Hövel, and Eckehard Schöll — Institut f. Theor. Physik, Sekr. EW 7-1, Technische Universität Berlin, Hardenbergstr. 36, 10623 Berlin, Germany

Time-delayed feedback methods have been widely used to control unstable dynamics in a huge variety of different fields ranging from chemical to optical systems. In the latter case, the time-delayed feedback can be realized experimentally by an optical resonator [1]. We present an application of a multiple time-delayed feedback scheme to a semiconductor laser system with undamped relaxation oscillations implemented as a model of Lang-Kobayashi type. We show that the control method is able to enhance the range of local stability of the lasing fixed point leading to continuous-wave operation by suppression of unwanted intensity pulsations. This local enhancement matches our findings on a generic normal-form model [2], but due to the self-feedback, multistable behavior can also occur in the form of delay-induced limit cycles and fixed points for certain choices of the control parameters.

[1] S. Schikora, P. Hövel, H. J. Wünsche, E. Schöll, and F. Henneberger: All-optical noninvasive control of unstable steady states in a semiconductor laser, Phys. Rev. Lett. 97, 213902 (2006).

[2] T. Dahms, P. Hövel, and E. Schöll: Control of unstable steady states by extended time-delayed feedback, Phys. Rev. E 76, 056201 (2007).