1,721,051 research outputs found
Multimode regimes in quantum cascade lasers with optical feedback
Full text linkWe study the instability thresholds of the stationary emission of a quantum cascade laser with optical feedback described by the Lang Kobayashi model. We introduce an exact linear stability analysis and an approximated one for an unipolar lasers, who does not exhibit relaxation oscillations, and investigate the regimes of the emitter beyond the continuous wave instability threshold, depending on the number and density of the external cavity modes. We then show that a unipolar laser with feedback can exhibit coherent multimode oscillations that indicate spontaneous phase-lockin
Pulsing and excitable solitons in a semiconductor laser with saturable absorber
No full textCavity solitons (CS) are controllable localized light peaks on a low-intensity, homogeneous (or quasi-homogeneous) background and offer a variety of applications from optical memories to all-optical delay lines. A semiconductor laser (VCSEL) with an intracavity saturable absorber realizes a cavity soliton laser, where the CS sit over a zero-intensity background, and may behave as independent microlasers. © 2011 IEEE
3D self-organized patterns in the field profile of a semiconductor resonator
No full textWe cast a suitable model to describe the 3D dynamics of the coherent field in a monolithic multi-quantum-well (MQW) microresonator within and beyond the mean field limit (MFL) and provide a stability analysis and discriminating criteria to predict 3D pattern formation. While for fast media spontaneous self-confinement leads to the formation of 3D dissipative addressable spatial solitons, we show that for carrier dynamics compatible with GaAs/GaAlAs MQW devices longitudinal self-confinement is hindered by carrier 'sleuth'. We discuss turnaround strategies there
Soliton dynamics in a semicondutor cavity soliton laser with broken translational symmetry
No full textSelf-mixing in multi-transverse mode semiconductor lasers: model and potential application to multi-parametric sensing
Full text linkA general model is proposed for a Vertical Cavity Surface Emitting Laser (VCSEL) with medium aspect ratio whose field profile can be described by a limited set of Gauss-Laguerre modes. The model is adapted to self-mixing schemes by supposing that the output beam is reinjected into the laser cavity by an external target mirror. We show that the self-mixing interferometric signal exhibits features peculiar of the spatial distribution of the emitted field and the target-reflected field and we suggest an applicative scheme that could be exploited for experimental displacement measurements. In particular, regimes of transverse mode-locking are found, where we propose an operational scheme for a sensor that can be used to simultaneously measure independent components of the target displacement like target translations along the optical axis (longitudinal axis) and target rotations in a plane orthogonal to the optical axis (transverse plane). (C) 2012 Optical Society of Americ
Nonlinear optical systems
No full textGuiding graduate students and researchers through the complex world of laser physics and nonlinear optics, this book provides an in-depth exploration of the dynamics of lasers and other relevant optical systems, under the umbrella of a unitary spatio-temporal vision. Adopting a balanced approach, the book covers traditional as well as special topics in laser physics, quantum electronics and nonlinear optics, treating them from the viewpoint of nonlinear dynamical systems. These include laser emission, frequency generation, solitons, optically bistable systems, pulsations and chaos and optical pattern formation. It also provides a coherent and up-to-date treatment of the hierarchy of nonlinear optical models and of the rich variety of phenomena they describe, helping readers to understand the limits of validity of each model and the connections among the phenomena. It is ideal for graduate students and researchers in nonlinear optics, quantum electronics, laser physics and photonics
Controlling cavity solitons by means of photorefractive soliton electro-activation
No full textWe consider a hybrid system consisting of a centrosymmetric photorefractive crystal in contact with a verticalcavity surface-emitting laser. We numerically investigate the generation and control of cavity solitons (CSs) by propagating a plane wave through electro-activated solitonic waveguides in the crystal. In such a compound scheme, which couples a propagative/conservative field dynamics to a bistable/dissipative one, we show that by changing the electro-activation voltage of the crystal, the CSs can be turned on and shifted with controlled velocity across the device section, on the scale of tens of nanoseconds. The configuration can be exploited for applications to optical information encoding and processin
Self-propelled soliton collisions in a semiconductor Cavity Soliton Laser
No full textSpontaneous soliton motion has been demonstrated in different systems supporting cavity solitons. Here we consider the case of a semiconductor laser with an intracavity saturable absorber, and study the interactions between self-propelled solitons when two of them collide or when they hit a localised defect in the material gain. According to the soliton velocity and impact parameter, destructive or repulsive collisions may take place between travelling solitons. On the other hand, a very rich variety of dynamical behaviors can be observed when a travelling soliton hits a material defect of comparable size. We observe soliton destruction, repulsive or attractive interaction and two trapped cases. The behavior is mainly determined by the gain contrast between the defect and the background
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