GIUDICI , Massimo

Cavity Solitons (CS) are stationary bright intensity peaks appearing in the transverse plane of an optical resonator driven by a coherent field (holding beam) and filled by a non linear medium. They can be individually switched on and off by a local perturbation in form of an addressing light pulse. The ability to control their location and...

The dynamics of semiconductor lasers exposed to optical feedback is the subject of this thesis. We have analyzed the instability leading to the so-called Low Frequency Fluctuations (LFF) appearing in the laser output intensity at moderate-to-strong feedback levels. We have investigated the dynamical nature of the LFF by means of non-standard...

In their recent letter...

International audience

Semiconductor lasers are tiny optoelectronic devices that are routinely used in countless applications ranging from computer pointing devices to optical data transmission. In addition to this, they can also serve as a versatile experimental platform for the exploration of dynamical systems and complex phenomena. In the following we discuss two...

International audience

We show experimentally that a electrically biased 200 $\mu m$ multi-transverse mode VCSEL can be passively mode locked using optical feedback from a distant Resonant Saturable Absorber Mirror (RSAM). Optical feedback from RSAM selects a tilted wave propagating along the transverse section of the VCSEL and leading to mode-locking of the external...

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The stochastic time scale of the mode hopping in a bulk semiconductor laser can be varied maintaining the symmetry of the residence times by a proper tuning of the laser substrate temperature and pumping current. While the addition of external noise to the pumping current affects the symmetry of the mode-hopping process, a sinusoidal modulation...

We study experimentally and theoretically the effects of crossed-polarization reinjection (XPR) on the output characteristics of a vertical-cavity semiconductor laser. We find a set of parameters values for which each polarization component develops a square-wave modulation at a period close to twice the reinjection delay. We analyze the...

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Beyond the chirality of light associated to polarization or spin, light beams can carry an additional orbital angular momentum due to the helicoidal structure of their phase front. This property, if combined with light localization could give rise to localized optical vortices, whose existence in nonlinear and dissipative optical systems is...

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In this work weexperimentally study mode-hopping in bulk semicnductor lasers. This stochastic process is ruled by Kramers statistics with a decay rate dependeing on the laser parameters of the temperature of the substrate and the puming current....

We report on experimental observation of localized structures in two mutually coupled broad-area semiconductor resonators. These structures coexist with a dark homogeneous background and they have the same properties as cavity solitons without requiring the presence of a driving beam into the system. They can be switched individually on and off...

Thermo-optical pulsing in semiconductor amplifiers is experimentally shown to correspond to a very common excitable scenario (the van der Pol–Fitzhugh–Nagumo system). Self-sustained oscillations appear in the sequence predicted by this simple dynamical model as we change either the injection level or the bias current. Periodic modulation of...

We present a method to measure the cavity length variations of a broad-area vertical-cavity surface-emitting laser. The method is based on the observation of an inhomogeneous nonlinear response of the system under coherent optical injection. Due to the presence of a cavity resonance frequency gradient in the system, the boundary of a...

Injection locking is a well known and commonly used method for coherent light amplification. Usually injection locking is done with a single-frequency seeding beam. In this work we show that injection locking may also be achieved in the case of multi-frequency seeding beam when slave laser provides sufficient frequency filtering. One relevant...

Injection locking is a well known and commonly used method for coherent light amplification. Usually injection locking is done with a single-frequency seeding beam. In this work we show that injection locking may also be achieved in the case of multi-frequency seeding beam when slave laser provides sufficient frequency filtering. One relevant...

International audience

We study the polarization-resolved dynamics of a vertical-cavity surface-emitting laser with mode-matched and polarization-preserving optical feedback. The total power can display low-frequency fluctuations, which are associated with drops in power of the dominant linearly polarized mode and with bursts of power of the depressed mode. However,...

The stable positions of localized structures depend on spatial gradients in the system parameters and on the local defects of the hosting medium. We propose a general method to disclose and visualize the local defects of the medium structure, otherwise not detected. The method is based on the observation of the spatiotemporal behavior of...