Numerical Simulation of Chaotic Laser Secure Communication. Qiang Ke

Transcription

1 Advanced Materials Research Online: ISSN: , Vols , pp doi:10.408/ 013 Trans Tech Publications, Switzerland Numerical Simulation of Chaotic Laser Secure Communication Qiang Ke Department of physics, Jiangxi normal university, Nanchang, Jiangxi, 3300, China Key Laboratory of Photoelectronics & Telecommunication of Jiangxi Province, Nanchang, Jiangxi, 3300, China Keywords: Chaotic Synchronization, Chaotic Laser Communication, Numerical Simulation Abstract. Using the idea of drive-response synchronization, we discuss the principle, numerical simulation of chaotic laser communication. Compared to traditional communications systems, the chaotic laser communication system has a well-kept secret performance, but the chaos synchronization requirements are very strict. Introduction How to enhance the security of communication is always the hotspot in the communication research area. Most of the existing secure schemes adopt the software approaches based on complicated calculations, thus, their security will not be guaranteed with the emergence of more efficient computers [1-5]. Since the 1983 University of California Professor Cai invented the famous Chua's circuit, the chaos began steering applications, especially the idea of chaos synchronization predicted by Pecora and Carroll laid a theoretical foundation for the application of chaos in communication, chaos synchronization and chaos communication has become a hot research topic of the communication field [6-1]. Different with the software schemes, chaotic laser secure communication makes use of the temporal randomness and wide bandwidth of chaotic laser signal; it belongs to secure communication based on physical phenomenon and is regarded as more secure. With the development of chaos technologies, chaotic laser secure communication will certainly has huge effect on secure communication, especially on military secure communication [13-16]. Chaos communication is divided into three main areas based on the inherent characteristics of the chaotic signal: (1) Secure communication. By the complex internal structure and the sensitivity of the initial conditions or parameters of the chaos signal, chaotic systems can easily produce a completely different chaotic orbit, it makes the structure of the chaotic system or long-term prediction of chaotic signal becomes very difficult. () Spread spectrum communication. Chaotic signal is inherently non-cyclical, so its spectral components in the band are continuous distribution, and the different chaotic circuit design can be customized with the spectral characteristics of chaotic signals. In communications, the broadband signal is often used to resist the adverse effects of the channel, especially some of the impact of narrowband. Thus the chaotic signal can be used as an easy-to-broadband signal is applied to spread spectrum communication. (3) Multiple access communication. Because of the chaotic signal is non-periodic, different chaotic systems or same chaotic system uses a different initial values or system parameters arising out of the chaotic signal have rapidly disappearing cross-correlation function. These signals can be seen as irrelevant meet certain sense orthogonal and they are prone to, and the number is huge, so it has a wide range of applications in multi-user communication [17-4]. Principle of laser chaos communication In order to more clearly describe the chaotic optical communication network, we give two optical communication system for comparison, as shown in Fig. 1(a) and (b). In the conventional optical communication system, optical carrier is a fixed intensity of light or a series of peak constant optical All rights reserved. No part of contents of this paper may be reproduced or transmitted in any form or by any means without the written permission of Trans Tech Publications, (ID: , Pennsylvania State University, University Park, USA-06/03/16,3:48:11)

2 Advanced Materials Research Vols pulse. The loading of the signal is achieved by intensity modulation, transmission bit "1" and bit "0" is completely different light intensity. By setting an appropriate threshold value, the receiving end can detect the light intensity, and restore the original signal. In Chaotic communication system, the intensity of the optical carrier is not maintained constant, but the random fluctuation, as shown in Fig. 1(c). The loading of information is achieved through a chaotic carrier modulation parameters, such as strength. For example, when transmission bit "1", the chaotic carrier unchanged, while when transmission bit "0", the chaotic carrier light intensity decreased by a certain proportion. Due to the chaotic carrier is undulating, so the direct use of the method of the simple measuring received chaotic signal strength can not detected original signal. To decode the original signal, it is necessary to copy a chaotic carrier at the receiving end. Subtraction the local copy from the received chaotic waveform, we can recover the original information [, 3]. Fig. 1 Comparison of chaotic communication system and conventional communication system (a) Conventional optical communication system with a fixed intensity of light, (b) Conventional optical communication system with a series of peak constant optical pulse, (c) Chaotic communication system Numerical simulation According to Pecora and Carroll drive - response synchronization method, the response system is driven by the x variable of the response system [1, ]. When two system parameters are the same and the initial value is not the same, the response maximum conditional Lyapunov exponents (CLE) is less than zero. The synchronization system composed by a drive system and response system is asymptotically stable. As shown in Fig. 1(c), we made the following numerical simulation. For the drive system x1 = (5α + 10)( y1 x1) y1 = (8 35α) x1 x1z1 + (9α 1) y z1 = x1y1 (8 + α) z1/ 3 1 (1)

3 57 Advances in Applied Science and Industrial Technology For the response system x y z With = (5α + 10)( y x ) = (8 35α) x1 x1z1 + (9α 1) y = x y (8 + α) z / 3 1 () α [0,1] (3) Small information signal is superimposed on the chaotic signal, using the pseudo-randomness of the chaotic signal, the information signal hidden in the seemingly messy chaotic signal. In the receiving end, using a chaotic synchronization signal cover up and restore the original information signal to achieve the purpose of secure transmission. Fig. shows the simulation waveforms based driver-response synchronization of chaotic masking secure communication. (a) (b) (c) (d) Fig. Based driver-response synchronization of chaotic masking secure communication simulation waveforms (a) Synchronization error curve, (b) Information signal, (c) Chaotic modulation signal, (d) Recovery signal Fig. (a) shows the synchronization of chaotic systems error curve, it can be seen that the system can achieve synchronization in a short period of time (about.4s). Fig. (b), (c), (d) shows the waveform of information signal, chaotic modulation signal and recovery signal. The system can quickly achieve synchronization, and can correctly recover the information signal. Due to the chaotic carrier is undulating, so the direct use of the method of the simple measuring received chaotic signal strength can not detected original signal.

4 Advanced Materials Research Vols Conclusions Using the idea of drive-response synchronization, we discuss the principle, numerical simulation of chaotic laser communication. The results show that, compared to traditional communications systems, the chaotic laser communication system has a well-kept secret performance, but the chaos synchronization requirements are very strict. This is a great challenge to the actual project implementation, but it is precisely the reason for optical secure communication using chaotic carrier, so both robustness and confidentiality is an important basis of the chaotic laser system research, design and evaluation. References [1] R. Roy, K.S. Physical Reviwe Letters, 1994,7(13) 009 [] Y. Liu, H. F. Chen, J. M. Liu, et al. Physical Review A, 001, 63(3) [3] D. Kanakidis, A. Argyris, D. Syvridis. Journal of Lightwave Technology, 003, 1(3)750 [4] D. W. Sukow, L. K. Blackburn, A. R. Spain, et al. Optics Letters, 004, 9(0)393 [5] F. Zhang, P. L. Chu, R. Lai, et al. IEEE Photonics technology letters, 005, 17(3)549 [6] D. W. Sukow, A. Gavrielides, T. Mclachlan, et al. Physical review A, 006, 74, 0381 [7] R. Vicente, C. R. Mirasso, I. Fischer. Optics Letters, 007, 3(4)403 [8] I. Gatare, M. Sciamanna, A. Locquet, et al. Optics Letters, 007, 3(1)169 [9] Y. Hong, M. W. Lee, J. Paul, et al. Optics Letters, 008, 33(6) 587 [10] A. Bogris, P. Rizomiliotis, E. Konstantinos, et al. IEEE Journal of Quantum Electronics, 008, 44() 119 [11] A. Mecozzi, C. Antonelli, V. A. Lodi, et al. Optics Letters, 009, 34(9)1387 [1] D. Z. Zhong, Z. M. Wu, Optics communications, 009, 8, 1631 [13] J. Z. Zhang, A. B. Wang, J. F. Wang, et al. Optics Express, 009, 17(8)6357 [14] J. Liu, Z. M. Wu, G. Q. Xia. Optics Express, 009, 17(15) 1619 [15] P. Li, J. G. Wu, Z. M. Wu, et al. Optics Express, 011,19()3911 [16] S. Y. Xiang, P. Wei, B. Luo, et al. Journal of Lightwave Technology, 011,9(14)173 [17] A. Argyris, D. Syvridis; L.Larger, et al. Nature, 005, 438: 343 [18] E. A. Shahverdiev, K. A. Shore. Physical Review E, 008, 77(5)05701 [19] S. Lepri, G. Giacomelli, A. Politi, et al. Physica (Amsterdam) D, 1993, 70: 35 [0] M. W. Lee, L. Larger, V. S. Udaltsov. et al. Optics Letters, 004, 9: 35 [1] C. Masoller, A. C. Mart ı. Physical Review Letters. 005, 94:13410 [] M. W. Lee, P. Rees, K. A. Shore, et al. IEE Proc.-Optoelectronics : 97 [3] W. H. Kye, M. Choi, M. W. Kim, et al. Physics Letters A, 004, 3: 338 [4] E. M. Shahverdiev, K. A. Shore. Optics Communications. 009, 8: 3568

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