Issue
EPL
Volume 79, Number 6, September 2007
Article Number 64003
Number of page(s) 6
Section Electromagnetism, Optics, Acoustics, Heat Transfer, Classical Mechanics, and Fluid Dynamics
DOI http://dx.doi.org/10.1209/0295-5075/79/64003
Published online 03 September 2007
EPL, 79 (2007) 64003
DOI: 10.1209/0295-5075/79/64003

Synchronization via clustering in a small delay-coupled laser network

C. M. González, C. Masoller, M. C. Torrent and J. García-Ojalvo

Departament de Física i Enginyeria Nuclear, Universitat Politècnica de Catalunya - Colom 11, E-08222 Terrassa, Barcelona, Spain


received 12 May 2007; accepted in final form 3 August 2007; published September 2007
published online 3 September 2007

Abstract
We study experimentally how synchronization emerges in a small network of delay-coupled lasers, as the coupling strength increases. Specifically, we optically couple three semiconductor lasers to each other via an external mirror. The system exhibits natural mismatches between its three elements, and is designed so that the coupling delays and strengths are non-uniform throughout the network. For weak coupling a cluster arises where two lasers synchronize their low-frequency dynamics; for stronger coupling all three lasers synchronize. A simple model gives good agreement with the experimental observations.

PACS
42.65.Sf - Dynamics of nonlinear optical systems; optical instabilities, optical chaos and complexity, and optical spatio-temporal dynamics.
05.45.Xt - Synchronization; coupled oscillators.
42.55.Px - Semiconductor lasers; laser diodes.

© Europhysics Letters Association 2007