Nonlinear dynamics is present everywhere in the natural environment. The engineered world, however, has been mostly built on linear concepts, though this has been changing recently. Semiconductor lasers are a good testbed as they are devices with many applications that can fairly easily be driven into nonlinear dynamical regimes. The resulting dynamics can be very fast (multi-GHz) and occur both in the optical and electronic worlds, with potential to interface the two.
We are especially interested in delay feedback systems, whose phase space is infinite-dimensional, and in which a large range of dynamics, from very simple, to very high-dimensional, can occur. Focus has been placed on two configurations: lasers with delayed optical and optoelectronic feedback. We have investigated both fundamental aspects, such as the sequence of bifurcations that can drive a laser from the CW regime to a fully developed chaotic regime, and applications to random number generation, reservoir computing, displacement sensing, and microwave photonics.