Experimental Investigation on the Effect of Message Encoding in Chaotic Optical Communication

Abstract

Chaotic optical communication at high bit rates has attracted great attention because of its potential application in secure communications. In a chaotic optical communication system, a message can participate in the dynamics of the nonlinear system and further affect the characteristics of the chaotic carrier waveform. Message encoding can also change the synchronization quality if an encoding scheme breaks the symmetry between a transmitter and a receiver. In this presentation, we experimentally investigate the influence of message encoding on the characteristics of chaotic dynamics, chaos synchronization, and chaotic communication, using three encoding schemes, namely chaos shift keying, chaos masking, and chaos modulation, with the setup of a chaotic optical communication system with optoelectronic feedback. The chaos shift keying and chaos modulation schemes are found to be able to increase the complexity of the chaotic carrier waveform due to the random nature of the encoded message. Meanwhile, the chaos shift keying and chaos masking schemes are found to deteriorate the synchronization quality when the amplitude of the message is increased. Consequently, only the chaos modulation scheme has the desired feature in increasing the complexity of the chaotic carrier waveform while maintaining the quality of chaos synchronization, which is an important feature in secure communication.