Controlling complex temporal and spatio-temporal dynamics in semiconductor lasers by delayed optical feedback

Abstract

All-optical schemes for controlling complex delay-induced and spatio-temporal dynamics in multi-stripe and broad-area semiconductor lasers are presented. The underlying control-principle is based on continuous delayed optical feedback. Its influence on the general spatiotemporal dynamics of semiconductor lasers is discussed. The delayed feedback control principle allows successful control of delay-induced chaotic behavior as well as the dynamic optical filamentation in broad-area and multi-stripe lasers. The suppression of spatiotemporal instabilities in semiconductor laser arrays is achieved by selectively stabilizing relevant transverse optical modes. The relevant values of delay-times and delay-phase are obtained from a nonlinear eigenmode analysis based on a complex extension of the Karhunen-Loeve decomposition. Thereby a destructive interference condition in the higher-order transverse modes conveying the instabilities is achieved. The stabilization technique is demonstrated on multi-stripe laser arrays. In high-power broad-area lasers the spatiotemporal filamentation processes occur on both macroscopic and microscopic scales. Numerical simulations on the basis of Maxwell-Bloch equations for spatially extended semiconductor lasers reveal the internal spatial and temporal scales on which control consequently has to occur. It is demonstrated that the combined filamentation and propagation effects may be controlled by suitable spatially structured delayed optical feedback allowing, in particular, the control of coherent regimes in originally temporally and spatially chaotic states.