Cavity length as a key to security in a chaotic optical communication scheme

Three diode lasers are used as message, transmitter and receive lasers. The message laser is amplitude modulated by a simple message and its output is optically coupled to the transmitter laser ensuring optical modulation of message. The transmitter laser is rendered chaotic by application of appropriate optical feedback. The receiver laser is used to decode the message. Effective signal masking is enhanced by the selection of an appropriate external cavity length, which could be a possible key for chaotic optical communication security.