Influence of the decoding process on the performance of chaos encrypted optical communication systems
Influence of the decoding process on the performance of chaos encrypted optical communication systems
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DOI：
10.1109/jlt.2005.859850
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发表时间：
2006-02
影响因子：
4.7
通讯作者：
D. Kanakidis;A. Argyris;A. Bogris;D. Syvridis
中科院分区：
文献类型：
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作者：
D. Kanakidis;A. Argyris;A. Bogris;D. Syvridis
研究了采用混沌调制（CM）编码方式的全光混沌通信系统的两种不同解码方法。发射机由一个外腔半导体激光器产生，因此，混沌载波，使用外部调制器调制。接收器或者是与发射器相同的单独半导体激光二极管，或者是耦合到外腔的激光二极管，分别形成开环或闭环配置。然后，通过计算由恢复数据的眼图提取的Q因子，当接收机采用两种不同的解码过程时，系统的性能进行评估。第一种解码方法依赖于广泛提出的、归一化到接收器的幅度输出的两个激光器的光学幅度输出的差，而第二种解码方法通过减去相应地耦合到发射器和接收器激光器的两个p-i-n光电二极管的电流输出而对应于更现实的情况。通过比较由两种解码方法提取的数值结果以及对于各种感兴趣的情况，例如对于几种消息比特率和不同激光器的驱动电流采用开环或闭环配置，将示出在某些情况下，两种解码方法导致显著不同的结果。
Two different decoding methods of an all-optical chaotic communication system are investigated when chaotic modulation (CM) encoding format is employed. The transmitter consists of an external cavity semiconductor laser generating, thus, a chaotic carrier, modulated using an external modulator. The receiver is either a solitary semiconductor laser diode identical to that of the transmitter or a laser diode coupled to an external cavity, forming an open- or a closed-loop configuration, respectively. The performance of the system is then evaluated by means of calculating the Q-factor extracted by the eye diagram of the recovered data when two different approaches of the decoding process for the receiver are adopted. The first decoding method relies on the widely proposed, normalized to the receiver's amplitude output, difference of the two lasers' optical amplitude outputs, while the second one corresponds to a more realistic case by subtracting the electrical current outputs of two p-i-n photodiodes coupled to the transmitter and receiver laser correspondingly. By comparing the numerical results extracted by the two decoding methods and for various cases of interest, such as employing open- or closed-loop configuration for several message bit rates and different lasers' driving current, it will be shown that, under certain circumstances, the two decoding methods result in significantly different results.