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We experimentally demonstrated a free space optical (FSO) transmission system with a pulse seedded wide-spectrum partially coherent beams (PCB) in a tunable turbulent channel. With 4Gbit/s on-off keying (OOK) modulation, the FSO transmission characters of the wide-spectrum laser are analyzed. The transmission link with the pulse seeded PCB shows the receive power fluctuation of 0.278dBm, receive SNR of 10.56dB, and the receive sensitivity of −34.8dBm, which is well beyond the performance of coherent beams (CB) and non-seeded PCB.

Most Chaotic synchronization control methods have some flaws which increase the security risks of the communication system. Attacker can reconstruct the chaotic system or estimate parameters by using the information of the chaotic system which can be obtained by analyzing the control signal. Therefore we propose a scheme's synchronization of Chua chaotic system with oscillating parameters under the impulsive control. In this paper, we proved that two systems can get synchronized without control signal transmitting.

Most Chaotic synchronization control methods have some flaws which increase the security risks of the communication system. Attacker can reconstruct the chaotic system or estimate parameters by using the information of the chaotic system which can be obtained by analyzing the control signal. Therefore we propose a scheme’s synchronization of Chua chaotic system with oscillating parameters under the impulsive control. In this paper, we proved that two systems can get synchronized without control signal transmitting.

Most properties of Rossler’s chaotic system satisfy with the requirements of secure communication and cryptography. Rossler’s Chaotic synchronization control can be the kernel technology in chaos-based secure commu-nication. In this paper we propose a hybrid Rossler chaotic synchronization control scheme which contains both continuous chaotic system and discrete chaotic system. It is impossible to reconstruct the whole system or estimate Rossler chaotic system‘s parameters. Lastly, we proved that two continuous systems can get synchronized without control signal transmitting.

Lu’s chaotic system is founded by Lu and chen in 2002 and its synchronization control can be the kernel technology in chaos-based secure communication. In this paper we propose a scheme’s synchronization of Lu’s chaotic system with oscillating parameters under the impulsive control. If oscillating parameters approach to 0, we proved that two systems can get synchronized. The chaos-based secure communication system with high secure level can be designed based on this scheme.

Many chaotic synchronization control methods have some flaws which increase the security risks of the communication system. In this paper we propose a hybrid Liu chaotic synchronization control scheme which contains both continuous Liu chaotic system and discrete Liu chaotic system and proved that two systems can get synchronized without control signal transmitting which has reduced the risk of the security.