Electro-optic delay devices with double feedback

8 pages, 15 figures.We analytically and numerically study the effect of an additional feedback in the semiconductor laser used to pump optoelectronic delay devices. We show that this additional feedback renders the system into chaotic regime for a broader parameter range and also induces a stronger chaotic behavior. We study the synchronization of this system as function of the parameter mismatch and show its capability for encoded message transmission.We gratefully thank Vasile Tronciu for helping us with the DDE-BIFTOOL program. As well, financial support from MICINN, Spain, and Feder under Project TEC2006-1009/MIC (PhoDECC) and Project FIS2004-00953 (CONOCE2) and by the EC Project PICASSO (IST-2005-34551) is acknowledged. R.M.Nguimdo also acknoledges the fellowship BES-2007-14627 under the FPI program of MICINN (Spanish Goverment).Peer reviewe

Role of the phase in the identification of delay time in semiconductor lasers with optical feedback

We consider a semiconductor laser with external optical feedback operating at a regime for which the delay time signature is extremely difficult to identify from the analysis of the intensity time series, using standard techniques. We show that such delay signature can be successfully retrieved by computing the same quantifiers from the phase, the real or the imaginary part of the field, even in presence of noise. Therefore the choice of the observable is determinant for parameter identification.Financial support from the Ministerio de Ciencia e Innovacion (MICINN), Spain, and the Fondo Europeo de Desarrollo Regional under projects FIS2007-60327 [Física Interdisciplinar de Sistemas Complejos (FISICOS)] and TEC2009-14101 [Delay-Coupled Diode Lasers for Photonic Applications (DeCoDicA)] and by the European Commission (EC) Project PHOCUS (FP7-ICT-2009-C- 240763) is acknowledged. R. M. Nguimdo also acknowledges fellowship BES-2007-14627 under the FPI program of MICINN.Peer reviewe

Effect of fiber dispersion on broadband chaos communications implemented by electro-optic nonlinear delay phase dynamics

We investigate theoretically and experimentally the detrimental e ect of ber dispersion on the synchroniza- tion of an optoelectronic phase chaos cryptosystem. We evaluate the root-mean square synchronization error and the cancellation spectra between the emitter and the re- ceiver in order to characterize the quality of the optical ber communication link. These two indicators explicitly show in temporal and spectral domain how ber dispersion does negatively a ect the phase chaos cancellation at the re- ceiver stage. We demonstrate that the dispersion manage- ment techniques used in conventional optical ber networks, such as dispersion-compensating modules/ bers or disper- sion shifted bers, are also e cient to strongly reduce the detrimental e ects of ber propagation in phase chaos com- munications. This compatibility therefore opens the way to a successful integration of more than 10-Gb/s phase chaos communications systems in existing networks, even when the ber link spans over more than 100 km.Peer reviewe

Electro-optic phase chaos systems with an internal variable and a digital key

OCIS codes:250.0250,060.0060,140.0140,190.0190)We consider an electro-optic phase chaos system with two feedback loops organized in a parallel configuration such that the dynamics of one of the loops remains internal. We show that this configuration intrinsically conceals in the transmitted variable the internal delay times, which are critical for decoding. The scheme also allows for the inclusion, in a very efficient way, of a digital key generated as a long pseudorandom binary sequence. A single digital key can operate both in the internal and transmitted variables leading to a large sensitivity of the synchronization to a key-mismatch. The combination of intrinsic delay time concealment and digital key selectivity provides the basis for a large enhancement of the confidentiality in chaos-based communications. © 2012 OSAThe authors thank L. Larger for valuable discussions. Financial support from MINECO, Spain, and Feder under Projects FIS2007-60327 (FISICOS) and TEC2009-14101 (DeCoDicA) and by the EC Project PHOCUS (FP7-ICT-2009-C-240763) is acknowledged. R.M.N. acknowledges fellowship BES-2007-14627 under the FPI program of MINECO. Also, he acknowledges the Research Foundation Flanders (FWO) for project support and fellowships, and the Belgian Interuniversity Attraction Pole Network [email protected] reviewe

Chaos and Synchronization in Opto-electronic Devices with Delayed Feedback

Tesis leída en la Universidad de las Islas Baleares, Palma de Mallorca (2011)Esta tesis tiene por objetivo general el estudio de la din´amica no lineal en distintos sistemas electro-´opticos. Por un lado se estudia la utilizaci´on de estos sistemas para generar caos de alta complejidad con vistas a comunicaciones ´opticas encriptadas y por otro como generadores de microondas de alta pureza espectral.financial support from MICINN, Spain, and Feder under Projects TEC2006-10009 (PhoDeCC), FIS2007-60327 (FISICOS) and TEC2009-14101 (DeCoDicA) and by EC Project PHOCUS (FP7-ICT-2009-C- 240763) is acknowledged, as well as the fellowship BES-2007-14627 under the FPI program of MICINN.Peer reviewe

Optical communications using semiconductor laser with electro-optical feedback devices

Tesis doctoral de la Universidad de las Islas Baleares.-- 61 pages.Since the development of telecommunications there is an ever growing interest in finding more secure ways to send the information. A possible way to do this is using the Vernam cipher[1] which is based on digital information (strings of N binary data.) where any analogic signal is first digitalized. Subsequently the digitalized message is convoluted with a given binary pattern (the key composed also of N binary data) so that it is scrambled and an eavesdropper cannot recover the message. The key is supposed to be known by the sender of the message and the new binary string is safely sent in a public communication channel [2]. Usually, the sender transmits this key to the addressee who uses to recover the original message by deconvoluting the sent message. Thus, with this technique, an eavesdropper has 2N possible messages and it is more difficult to know which is the original one.This work is the Thesis for the Master in Physics of the Universitat de les Illes Balears, and it has been done thanks to the program “Formación de personal de investigación” (FPI). The Spanish Government, as well as the University of Balearic Islands.Peer reviewe

Enhanced performances of a photonic reservoir computer based on a single delayed quantum cascade laser

In previous works, it has been shown that reservoir computing (RC) systems using a laser subject to a delayed optical feedback and stabilized by an injected signal may be highly sensitive to the feedback phase. In this Letter, we show that a RC system using a single quantum cascade laser subject to a delayed optical feedback but without injection is robust to the feedback phase for a large range of values of the parameters.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Digital Key for Chaos Communication Performing Time Delay Concealment

PACS numbers: 42.15.Eq, 05.45.Jn, 05.45.Tp, 05.45.VxWe introduce a scheme that integrates a digital key in a phase-chaos electro-optical delay system for optical chaos communications. A pseudorandom binary sequence (PRBS) is mixed within the chaotic dynamics in a way that a mutual concealment is performed; e.g., the time delay is hidden by the binary sequence, and the PRBS is also masked by the chaos. In addition to bridging the gap between algorithmic symmetric key cryptography and chaos-based analog encoding, the proposed approach is intended to benefit from the complex algebra mixing between a (pseudorandom) Boolean variable, and another continuous time (chaotic) variable. The scheme also provides a large flexibility allowing for easy reconfigurations to communicate securely at a high bit rate between different systems.Financial support from MICINN, Spain, and Feder under Projects TEC2006-10009 (PhoDeCC), FIS2007- 60327 (FISICOS) and TEC2009-14101 (DeCoDicA) and by EC Project PHOCUS (FP7-ICT-2009-C-240763) is acknowledged. R. M. N. also acknowledges the fellowship BES-2007-14627 under the FPI program of MICINN.Peer reviewe

On the Phase Noise Performance of Nonlinear Double-Loop Optoelectronic Microwave Oscillators

We consider an optoelectronic oscillator for ultrapure microwave generation with two nonlinearly coupled delay loops in which the output of one of the loops modulates the other. We introduce a suitable dynamical model and study the phase noise performance. Tuning the parameters of the second loop allows to reduce the detrimental effect of the multiplicative phase noise and damp delay-induced spurious peaks. Besides, the nonlinear dynamics allows for stable microwave emission with larger amplitude than a single loop system.Financial support from MICINN, Spain, and Feder under Projects TEC2006-10009 (PhoDeCC), FIS2007-60327 (FISICOS) and TEC2009- 14101 (DeCoDicA) and by EC Project PHOCUS (FP7-ICT-2009-C-240763) is acknowledged. R.M.N. also acknowledges the fellowship BES-2007-14627 under the FPI program of MICINN.Peer reviewe