Stability of the nonlinear dynamics of an optically injected VCSEL

Automated protocols have been developed to characterize time series data in terms of stability. These techniques are applied to the output power time series of an optically injected vertical cavity surface emitting laser (VCSEL) subject to varying injection strength and optical frequency detuning between master and slave lasers. Dynamic maps, generated from high resolution, computer controlled experiments, identify regions of dynamic instability in the parameter space. © 2012 Optical Society of America

Uncertainty in interpulse time interval evaluated as a new measure of nonlinear laser dynamics

A variety of dynamical outputs can be generated with an optically injected solid state laser by varying the intensity of the injection from the master into the slave laser, and/or the frequency detuning between the master and slave lasers. The system is capable of generating regular laser pulses with constant amplitude and robust period, as well as irregular pulses with chaotically varying amplitude. We propose that a mapping of the variation in interpulse duration of an optically injected solid state laser is a useful tool to facilitate identification of different dynamical regions within the parameter space.3 page(s

Suppressing aeroelastic instability by means of broadband targeted energy transfers, part 2: Experiments

This paper presents experimental results corroborating the analysis developed in the companion paper, Part I (Lee, Y., Vakakis, A., Bergman, L., McFarland, M., and Kerschen G., "Suppression Aeroelastic Instability Using Broadband Passive Targeted Energy Transfers, Part 1: Theory," AIAA Journal, Vol. 45, No. 3, 2007, pp. 693-711), and demonstrates that a nonlinear energy sink can improve the stability of an aeroelastic system. The nonlinear energy sink was, in this case, attached to the heave (plunge) degree of freedom of a rigid airfoil which was supported in a low-speed wind tunnel by nonlinear springs separately adjustable in heave and pitch. This airfoil was found to exhibit a at flow speeds above the critical ('flutter") speed of 9.5 m/s, easily triggered by an initial heave displacement. After attachment of a single degree of freedom, essentially nonlinear energy sink to the wing, the combined system exhibited improved dynamic response as measured by the reduction or elimination of limit cycle oscillation at flow speeds significantly greater than the wing's critical speed. The design, application, and performance of the nonlinear energy sink are described herein, and the results obtained are compared to analytical predictions. The physics of the interaction of the sink with the wing is examined in detail