Secure Optical QAM Transmission Using Chaos Message Masking

Abstract

Abstract This work presents the joint use of advance modulation scheme i. e. m-QAM and optical chaos to combine the best of the two advantages i. e. higher data rates and security. A semiconductor laser diode is driven into chaotic region using direct modulation scheme and 4-QAM signal is added by Chaos message masking (CMS). The chaotically masked data stream is transmitted over an optical communication link to investigate the propagation issues and synchronization of chaos at the receiver. The transmitted chaos is synchronized at the receiver to unmask the QAM stream and binary data by using subtraction rule and conventional QAM demodulator, respectively. The deterioration of constellation diagrams and bit error rate found dependent upon transmitter/receiver synchronization and link parameters. The use of 4-QAM chaotic scheme is extendable to m-QAM and is applicable to long haul, short haul point to point and for passive optical networks.