Chaos Applications in Optical Communications

The first part of this chapter provides an introduction to the cryptographic techniques applied in contemporary communication systems using algorithmic data encryption. However, there are several other techniques that may provide additional security in the transmission line, taking advantage of the properties of the communication type and the transmission medium. Optical communication systems that exchange light pulses can exploit some properties in the physical layer for securing the communicating parts. Such properties lead to data encryption through methods such as quantum cryptography and chaos encryption, which are described in the second part. Since this chapter focuses on the

chaos encryption technique

, the third part describes the potential of optical emitters to generate complex chaotic signals using different techniques. Such chaotic carriers can be potentially used for broadband message encryption. The fourth part analyzes the phenomenon of synchronization between chaotic signals. A receiver capable of synchronizing with the emitted carrier can reject the carrier as well and recover the encrypted message. The fifth part presents various message encryption techniques that can be applied for optical communication systems that are able to operate on the basis of a chaotic carrier. Additionally, an example of a preliminary system that has been tested successfully is presented. In the sixth part, contemporary systems based on all-optical or optoelectronic configurations are presented, incorporating also as the transmission medium fiber spools or installed fiber networks. Finally, the seventh part concludes with the potential of this method to guarantee secure optical communications.