Berlin 2012 – wissenschaftliches Programm

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DY: Fachverband Dynamik und Statistische Physik

DY 22: Posters I

DY 22.48: Poster

Mittwoch, 28. März 2012, 17:00–19:00, Poster A

Complex Dynamics of Quantum Dot Lasers Under Optical Injection — •Christian Otto, Johannes Pausch, Kathy Lüdge, and Eckehard Schöll — Technische Universität Berlin, Germany

We study the influence of nonlinear carrier lifetimes on the complex dynamics of a quantum dot (QD) laser under optical injection.

The dynamics of a QD laser is crucially affected by the damping rate of its turn-on relaxation oscillations, which in turn is determined by the carrier lifetimes in the QDs. We derive the carrier lifetimes by microscopical calculations of the Coulomb scattering rates between the discrete QD levels and the surrounding quantum well acting as a carrier reservoir. This yields non-constant and unequal carrier lifetimes for electrons and holes in the QDs, which are nonlinear functions of the reservoir carrier densities.

Depending on the band-structure, the lifetimes of electrons and holes in the QDs can be similar or drastically different. Further they can be fast or slow compared to the carrier lifetimes in the carrier reservoir. We study the locking behavior as well as more complex bifurcation scenarios close to the boundaries and outside of the locking region. The dynamics is investigated by means of direct numerical integration and path continuation techniques.

A stronger damping of the turn-on relaxation oscillations leads to smaller regions of complex dynamics and enlarges the range of stable frequency-locked continuous wave operation. An optimal value of the carrier lifetimes is found that maximizes the range of stable operation.