Optical Solitons in semiconductor-based microdevices as a means to encode and process information

Cavity solitons (CSs) are bidimensional localized structures (LSs) that form in the transverse profile of the radiation field propagating in a coherently driven nonlinear optical resonator with high Fresnel number.

These bright intensity peaks sitting on a homogeneous background are the effect of the competition-balance between diffraction and self-focusing in presence of a dissipative feedback [1]. A single CS can be turned on and off independently from the others by means of suitable addressing beams and moves in presence of amplitude or phase gradients of the injected field. Cavity solitons have been predicted and experimentally observed in a broad area VCSEL in 2002 [2,3]. The fundamental interest of CSs lies in their being an example of self-organization in a complex dynamical system.

Their unique proprieties (multistability, plasticity, etc) make CSs in VCSELs excellent candidates optical “bits” for applications to information storage and processing [3]: Parallel and reconfigurable optical memories, all-optical logic gates and circuits, optical delay lines, serial to parallel converters.

The CSs sensitivity to gradients of the cavity detuning induced by device defects allows to conceive "soliton force" microscopes inhomogeneities.

Note: Recent theoretical results obtained in a prototypical 2-level atom resonator show three dimensional light self-localization in form of cavity light bullets (CLBs) [4].

Our main research activities focus on the theoretical study of self-confinement in two (CSs) and three spatial dimensions (CLBs) in semiconductor lasers.

In particular we collaborate at the theoretical prediction of the existence and manipulability of cavity solitons in VCSEL [3] and of cavity light bullets in a prototypical nonlinear resonator [4].

In the framework of the national project ”Futuro in Ricerca” FIRB-grant PHOCOS we recently started to investigate the generation and control of CSs in a hybrid conservative and dissipative system consisting of a centrosymmetric photorefractive crystal in contact with a broad area VCSEL.

Main collaborations:

Università dell’Insubria (Como, IT), Institut non linéaire de Nice (FR), Laboratoire de Photonique et de Nanostructures (Paris, FR), University of Strathclyde (Glasgow, UK).

References:

[1] L. A. Lugiato, IEEE J. Quantum Electron. 39, 193 (2006).

[2] L. Spinelli, G. Tissoni, M. Brambilla, F. Prati, and L. A. Lugiato, Phys. Rev. A 58, 2542 (1998).

[3] S. Barland, J. Tredicce, M. Brambilla, L. A. Lugiato, S. Balle, M. Giudici, T. Maggipinto, L. Spinelli, G. Tissoni, T. Knödl, M. Miller and R. Jäger, Nature 419, 699 (2002).

[4] M. Brambilla, T. Maggipinto, G. Patera, and L. Columbo, Phys. Rev. Lett. 93, 203901 (2004).