title: Bifurcation diagram of a complex delay-differential equation with cubic nonlinearity.
abstract: We reduce the Lang-Kobayashi equations for a semiconductor laser with external optical feedback to a single complex delay-differential equation in the long delay-time limit. The reduced equation has a time-delayed linear term and a cubic instantaneous nonlinearity. There are only two parameters, the real linewidth enhancement factor and the complex feedback strength. The equation displays a very rich dynamics and can sustain steady, periodic, quasiperiodic, and chaotic regimes. We study the steady solutions analytically and analyze the periodic solutions by using a numerical continuation method. This leads to a bifurcation diagram of the steady and periodic solutions, stable and unstable. We illustrate the chaotic regimes by a direct numerical integration and show that low frequency fluctuations still occur.
authors.affiliation: Optique Nonlinéaire Théorique, Université Libre de Bruxelles, Campus Plaine, Code Postale 231, 1050 Brussels, Belgium.
authors.forename: D
authors.initials: D
authors.lastname: Pieroux
authors.forename: Paul
authors.initials: P
authors.lastname: Mandel