Observation of electro-activated localized structures in broad area VCSELs

We demonstrate experimentally the electro-activation of a localized optical structure in a coherently driven broad-area vertical-cavity surface-emitting laser (VCSEL) operated below threshold. Control is achieved by electro-optically steering a writing beam through a pre-programmable switch based on a photorefractive funnel waveguide.Comment: 5 Figure

Control of spatiotemporal rogue waves by harmonic pump modulation in a semiconductor laser with a saturable absorber

Through numerical simulations, statistical and dynamical properties of extreme events in a broad-area semiconductor laser with intracavity saturable absorber are investigated. By inclusion of a diffusion coefficient for the field, formation of rogue waves in a state of extended turbulence is studied and shown to be affected by harmonic perturbations. In particular, we propose a control technique based on periodic modulation of the pump parameter which can either drive the state of the system closer to or away from the chaotic attractors respectively enhancing or suppressing the generation of rogue waves. By statistical and dynamical analysis of the events in terms of intensity and optical gain, we show that when the system is under resonant modulation with frequency close to that of the dominant oscillations in the turbulent state (which is equal to the relaxation oscillation frequency typical of semiconductor lasers), more rogue waves are triggered with larger intensities and shorter lifetimes. On the other hand, off-resonant modulations restrain the formation of rogue waves where they appear in lower intensities and longer lifetimes. An example of special cases where the proposed scheme can completely forbid or allow the emission of rogue waves is also presented

Cavity-soliton motion in the presence of device defects

Cavity solitons (CSs) are localized structures appearing as single intensity peaks in the homogeneous background of the field emitted by a nonlinear (micro) resonator driven by a coherent field (holding beam). By introducing a phase gradient in the holding beam, it is possible to induce CS drift. This motion is strongly influenced by the presence of defects in the device structure. We analyze numerically two situations that appeared in the experiments. In the first one, a structure is self-generated on the defect and a regular sequence of moving CS originates from it. We investigate the properties of this \u201ctap\u201d of CS as a function of the defect characteristics and of the parameters values. The second situation corresponds to the interaction between a moving CS and a defect, which plays a fundamental role in CS applications such as the delay line or the shift register

All-optical delay line using semiconductor cavity solitons (vol 92, 011101, 2008)

Correction of Pedaci, F. and Barland, S. and Caboche, E. and Firth, W.J. and Oppo, G.L. and Tredicce, J.R. and Ackemann, T. and Scroggie, A.J. (2008) All-optical delay line using semiconductor cavity solitons. Applied Physics Letters, 92 (1). ISSN 0003-695

All-optical delay line using semiconductor cavity solitons

An all-optical delay line based on the lateral drift of cavity solitons in semiconductor microresonators is proposed and experimentally demonstrated. The functionalities of the device proposed as well as its performance is analyzed and compared with recent alternative methods based on the decrease of group velocity in the vicinity of resonances. We show that the current limitations can be overcome using broader devices with tailored material responses

Interaction of two modulational instabilities in a semiconductor resonator

The interaction of two neighboring modulational instabilities in a coherently driven semiconductor cavity is investigated. First, an asymptotic reduction of the general equations is performed in the limit of a nearly vertical input-output characteristic. Next, a normal form is derived in the limit where the two instabilities are close to one other. An infinity of branches of periodic solutions are found to emerge from the unstable portion of the homogeneous branch. These branches have a nontrivial envelope in the bifurcation diagram that can either smoothly join the two instability points or form an isolated branch of solutions

Microresonator defects as sources of drifting cavity solitons

Cavity solitons (CS) are localized structures appearing as single intensity peaks in the homogeneous background of the field emitted by a nonlinear (micro)resonator. In real devices, their position is strongly influenced by the presence of defects in the device structure. In this Letter we show that the interplay between these defects and a phase gradient in the driving field induces the spontaneous formation of a regular sequence of CSs moving in the gradient direction. Hence, defects behave as a device built-in CS source, where the CS generation rate can be set by controlling the system parameters

Progetto firb futuro in ricerca "phocos" (spatial solitons composites bridging photorefractive and cavity optical structures), Anno 2008 - Protocollo: RBFR08E7VA_002

L'unit\ue0 di ricerca INS svilupper\ue0 i modelli e le basi teorico-numeriche per l'elaborazione del paradigma "composti Solitoni di Cavit\ue0 (CS) - Solitoni Fotorifrattivi (PRS)" e per la comprensione e la progettazione di esperimenti dedicati, che saranno eseguiti dall'unit\ue0 di ricerca dell'Universit\ue0 dell'Aquila (AQ). Obiettivo I: Guidare un CS mediante elettro-attivazione di una struttura PRS. Obiettivo II: Controllare un PRS mediante un CS Obiettivo III: Solitoni composti PRS-C