Search query: Synchronization and secure communication in time delayed semiconductor laser systems

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abstract: Abstract We investigate the synchronization in coupled time delayed semiconductor laser models without and under the influence of external noise sources. The synchronization and its robustness are observed by mean synchronization error and the effect of parameter mismatch respectively. A communication scheme is introduced based on symmetrical encryption and decryption method in the frame of coupled synchronized lasers with optical feedback. The scheme is effective irrespective of the nature and dynamics of the transmitted signal. The security of the scheme is verified by the effect of relative parameter mismatch, key sensitivity frequency and cross correlation analysis. Numerical results support the proposed analysis.
author_names: Thang Manh Hoang

Sanjay Kumar Palit

Sayan Mukherjee

Santo Banerjee
title: Synchronization and secure communication in time delayed semiconductor laser systems
year: 2016

abstract: An observer design problem for a class of nonlinear time delay systems subject to white Gaussian noise is studied. The problem addressed is the design of a full state observer based on the extended Kalman filter (EKF) in which two terms are added to the Riccati differential equation. One of those makes the system robust to noise influences, and the other one is utilized for dealing with the delayed state. A Lyapunov Krasovskii functional is used for giving sufficient conditions for local stability of the reconstruction error dynamics. A hybrid chaotic cryptosystem procedure based on the n shift cipher is combined with synchronization based on the EKF for developing a secure communication system. A semiconductor laser with optical feedback is employed as a chaotic signal generator in which a full state estimation via the EKF is achieved.
author_names: Oscar Hugues-Salas

K Alan Shore
title: An Extended Kalman Filtering Approach to Nonlinear Time Delay Systems: Application to Chaotic Secure Communications
venue: IEEE Transactions on Circuits and Systems I: Regular Papers
year: 2010

abstract: A novel bandwidth enhanced bidirectional phase chaotic secure communication system with time delay signature (TDS) concealment is proposed and analyzed by numerical simulation. This bidirectional system based on two mutually coupled electro optic (MCEO) phase feedback loops is driven by a common all optical (AO) chaotic source. The AO driving source makes the amplitude and phase terms in the Ikeda based MCEO equation chaotic. Two mutually coupled optoelectronic delayed feedback loops also greatly increase the complexity of the chaotic carrier. By replacing the semiconductor laser in the existing bidirectional communication scheme with an electro optic feedback loop, the problems of narrow carrier bandwidth and poor synchronization performance can be compensated. Compared to the single MCEO system, the permutation entropy of the AO MCEO cascaded system with a bit rate of 10 Gbit/s is improved by 0.13 to 0.98. The TDS of the AO MCEO system is suppressed 35 times to less than 0.01 to be completely hidden when the EO gain is reduced by half to 2.75. The chaos effective bandwidth is increased by 5 GHz to 32.05 GHz, and the spectrum flatness is reduced by 0.33 dB/Hz to 0.82 dB/Hz. Meanwhile, the security is further enhanced by reducing the cross correlation coefficient to 0.001 between the AO driving source and the electro optical chaotic carrier. The results show that the proposed model has potential applications in bandwidth enhanced bidirectional secure chaotic systems.
author_names: Tianfeng Lu

Hongxiang Wang

Yuefeng Ji
title: Wideband complex enhanced bidirectional phase chaotic secure communication with time delay signature concealment.
venue: Chaos
year: 2020

abstract: This study concentrates on the transmitter operating in the short cavity regime. Broadband chaotic dynamics of the transmitter is demonstrated with corresponding nearly "white" rf spectra. Under these conditions, the receiver laser is synchronized, revealing a conspicuous potential for secure, broadband and multi Gigabit rate communication systems, which are based on chaotic carriers and chaos synchronization. The influence of the injection current I/sub p/ and the delay time /spl tau//sub del/ on the dynamics of the transmitter laser operating in the short cavity regime is experimentally studied, in which the delay time of the optical feedback /spl tau//sub del/ is shorter than the period of the relaxation oscillation frequency of the laser /spl tau//sub ro/ It is demonstrated that for a well adjusted feedback phase and moderate I/sub p/ the bandwidth of the dynamics can be drastically enhanced compared to the results reported for lasers with longer cavities. Results show an almost "white" rf spectra extending up to frequencies of several GHz. The bandwidth of the system increases by reducing /spl tau//sub del/ or by increasing I/sub p/ respectively. Furthermore, the autocorrelation function of the dynamics decays rapidly, indicating a strong nonlinearity in the system. These properties are crucial demands on chaotic carriers for the realization of secure communication systems based on synchronization of chaotic carriers.
author_names: Michael Peil

Tilmann Heil

L Fischer

W Elsafler

Javier M Buldu
title: Chaos synchronization of semiconductor laser systems in an open loop configuration: the short cavity regime and its potential for secure communication systems
venue: 2003 European Quantum Electronics Conference. EQEC 2003 (IEEE Cat No.03TH8665)
year: 2003

abstract: Abstract In this paper, we propose and study theoretically a novel architecture, which combines all optical intensity chaos and electrooptical phase chaos generator, allows for bidirectional secure communication. The configuration includes three all optical chaotic semiconductor lasers and two identical phase chaos electrooptic delayed oscillators in the optic fiber link. We investigate the complexity degree of this chaotic time trace generated in this system and the concealment of the time delay signature (TDS) and systematically analyze the influence of the parameter mismatch on synchronization performance We demonstrate that the system can generate the chaos with high complexity degree through a calculation of the largest Lyapunov exponent (LLE) Lempel Ziv complexity (LZC) permutation entropy (PE) and fractal box counting dimension (FBCD) the TDS of an electro optical delayed oscillator is concealed by calculating the autocorrelation function (ACF) and the delayed mutual information (DMI) the parameter mismatches, such as the TDS, the bias current, the line width enhancement factor (LWEF) etc. have the influence on the synchronization performance; the changes of the bit rate and the modulation index have the influence on Q factor of the system. Moreover, our numerical simulations also reveal that, under the parameter match condition the delayed chaotic dynamics can be identically synchronized and the synchronization solution is robust. At last, we successfully achieve the simultaneously bidirectional exchange of the messages introduced on the two sides of a link.
author_names: Qiliang Li

Qi Bao
title: Bidirectional communication with time delay concealment in a system combining all optical intensity and electrooptical phase chaos
year: 2020

abstract: Abstract We numerically investigate the synchronization performance of unidirectionally and bidirectionally coupled chaotic semiconductor lasers subject to multiple modulated time delays optical feedbacks. Moreover, by studying the autocorrelation function of the coherent feedback semiconductor laser output, we find that the signatures of time delays can be erased in systems incorporating modulated feedback time delays, which largely improve the system security. Finally, chaos masking switching (CMS) is utilized to examine the communication ability. Numerical results indicate that the messages could be successfully recovered both in unidirectionally and bidirectionally coupled lasers, which confirms the possibility of applying multiple modulated delay system in optical chaos secure communication.
author_names: Juju Hu

Kehui Jia

Jun-shan Ma
title: Chaos synchronization and encoding in coupled semiconductor lasers of multiple modulated time delays
year: 2011

abstract: The synchronization in multiple modulated time delay chaotic lasers subject to incoherent optical feedbacks and incoherent optical injection is numerically investigated,in which the semiconductor lasers are subject to incoherent injection that fine tuning of optical frequency is not required.Otherwise,by studying the autocorrelation function of the incoherent feedback semiconductor laser output,it is found that the signatures of time delays can be erased in systems incorporating modulated feedback time delays,which property can improve the system security and is of importance for the suitability of such laser systems for secure chaos based communication systems.Finally,the encryption method of CSK and CMS is respectively utilized to examine the communication ability of the unidirectionlly and bidirectionly coupled system.
author_names: Wan Yun-hui
title: Chaos synchronization and encoding in coupled semiconductor lasers of multiple modulated time delays
year: 2010

abstract: A closed loop system (CLS) of quantum dot semiconductor laser (QDL) with optical feedback is theoretically studied in this work. The CLS studied under two types of time delay (short and long) The system transit to chaos under short delay times, which important in secure optical communications. A complete synchronization was obtained at long delay time which is also important in the of coding and decoding for communication security applications.
author_names: Basim Abdullattif Ghalib

Rajaa Hussein Abd Ali

Amin Habbeb Al-Khursan
title: Effect of short and long delay times on closed loop system of quantum dot semiconductor lasers
year: 2020

abstract: To exam the chaotic dynamics of multiple modulated delays system, the synchronization in multiple constant and modulated time delay chaotic lasers subject to incoherent optical feedbacks and incoherent optical injection is numerically investigated, in which the semiconductor lasers are subject to incoherent injection that fine tuning of optical frequency is not required. Furthermore, the autocorrelation function of the incoherent feedback semiconductor laser output is also investigated. The results indicate that high quality of synchronization can be obtained under both the cases. However, the signatures of time delays under modulated delays case can be hidden, which largely improves the system security and is important for the suitability of such laser systems for secure chaos based communication systems.
author_names: Hu Ju-ju

Ma Jun-shan
title: Chaos synchronization in coupled semiconductor lasers of multiple modulated time delays
year: 2010

abstract: By studying the autocorrelation function of the optoelectronic feedback semiconductor laser output we establish that the signatures of time delays can be erased in systems incorporating modulated feedback time delays. This property is of importance for the suitability of such laser systems for secure chaos based communication systems. We also make the first report on chaos synchronization in both unidirectionally and bidirectionally coupled multiple time delay chaotic semiconductor lasers with modulated optoelectronic feedbacks.
title: Erasure of Time Delay Signatures in the Output of an Optoelectronic Feedback Laser with Modulated Delays and Chaos Synchronization
year: 2009