Performance comparison of different encoding schemes in chaotic optical communication systems

This study aims to determine the best encryption technique to assure the security of transmitted information. The authors concentrate on three main encryption schemes: CSK (chaos shift keying), CMO (chaos modulation) and CMA (chaos masking). In CSK the message is encoded by switching the transmitter injected current between two states, CMO is based on the modulation of chaotic carrier generated by the transmitter laser and finally in CMA the encoding is achieved by adding the message to the chaotic transmitter output. This study also evaluates the efficiency of the masking and its dependence on the message amplitude and bit rate. The quality of the message recovery is investigated through the correlation coefficient technique. Particular attention is paid to the influence of the parameter mismatch between emitter and receiver.